Publications by authors named "Thomas W Prior"

78 Publications

Midostaurin reduces relapse in FLT3-mutant acute myeloid leukemia: the Alliance CALGB 10603/RATIFY trial.

Leukemia 2021 Mar 2. Epub 2021 Mar 2.

Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.

The prospective randomized, placebo-controlled CALGB 10603/RATIFY trial (Alliance) demonstrated a statistically significant overall survival benefit from the addition of midostaurin to standard frontline chemotherapy in a genotypically-defined subgroup of 717 patients with FLT3-mutant acute myeloid leukemia (AML). The risk of death was reduced by 22% on the midostaurin-containing arm. In this post hoc analysis, we analyzed the cumulative incidence of relapse (CIR) on this study and also evaluated the impact of 12 4-week cycles of maintenance therapy. CIR analyses treated relapses and AML deaths as events, deaths from other causes as competing risks, and survivors in remission were censored. CIR was improved on the midostaurin arm (HR = 0.71 (95% CI, 0.54-0.93); p = 0.01), both overall and within European LeukemiaNet 2017 risk classification subsets when post-transplant events were considered in the analysis as events. However, when transplantation was considered as a competing risk, there was overall no significant difference between the risks of relapse on the two randomized arms. Patients still in remission after consolidation with high-dose cytarabine entered the maintenance phase, continuing with either midostaurin or placebo. Analyses were inconclusive in quantifying the impact of the maintenance phase on the overall outcome. In summary, midostaurin reduces the CIR.
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http://dx.doi.org/10.1038/s41375-021-01179-4DOI Listing
March 2021

Spinal Muscular Atrophy: Mutations, Testing, and Clinical Relevance.

Appl Clin Genet 2021 25;14:11-25. Epub 2021 Jan 25.

Pathology, University Hospitals Center for Human Genetics, Cleveland, OH, USA.

Spinal muscular atrophy (SMA) is a heritable neuromuscular disorder that causes degeneration of the alpha motor neurons from anterior horn cells in the spinal cord, which causes severe progressive hypotonia and muscular weakness. With a carrier frequency of 1 in 40-50 and an estimated incidence of 1 in 10,000 live births, SMA is the second most common autosomal recessive disorder. Affected individuals with SMA have a homozygous loss of function of the survival motor neuron gene on 5q13 but keep the modifying gene. The most common mutation causing SMA is a homozygous deletion of the exon 7, which can be readily detected and used as a sensitive diagnostic test. Because produces a reduced number of full-length transcripts, the number of copies can modify the clinical phenotype and as such, becomes an essential predictive factor. Population-based SMA carrier screening identifies carrier couples that may pass on this genetic disorder to their offspring and allows the carriers to make informed reproductive choices or prepare for immediate treatment for an affected child. Three treatments have recently been approved by the Food and Drug Administration (FDA). Nusinersen increases the expression levels of the SMN protein using an antisense oligonucleotide to alter splicing of the transcript. Onasemnogene abeparvovec is a gene therapy that utilizes an adeno-associated virus serotype 9 vector to increase low functional SMN protein levels. Risdiplam is a small molecule that alters splicing in order to increase functional SMN protein. Newborn screening for SMA has been shown to be successful in allowing infants to be treated before the loss of motor neurons and has resulted in improved clinical outcomes. Several of the recommendations and guidelines in the review are based on studies performed in the United States.
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http://dx.doi.org/10.2147/TACG.S239603DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7846873PMC
January 2021

Characterization of Reference Materials for Spinal Muscular Atrophy Genetic Testing: A Genetic Testing Reference Materials Coordination Program Collaborative Project.

J Mol Diagn 2021 01 14;23(1):103-110. Epub 2020 Nov 14.

Informatics and Data Science Branch, Division of Laboratory Systems, CDC, Atlanta, Georgia. Electronic address:

Spinal muscular atrophy (SMA) is an autosomal recessive disorder predominately caused by bi-allelic loss of the SMN1 gene. Increased copies of SMN2, a low functioning nearly identical paralog, are associated with a less severe phenotype. SMA was recently recommended for inclusion in newborn screening. Clinical laboratories must accurately measure SMN1 and SMN2 copy number to identify SMA patients and carriers, and to identify individuals likely to benefit from therapeutic interventions. Having publicly available and appropriately characterized reference materials with various combinations of SMN1 and SMN2 copy number variants is critical to assure accurate SMA clinical testing. To address this need, the CDC-based Genetic Testing Reference Materials Coordination Program, in collaboration with members of the genetic testing community and the Coriell Institute for Medical Research, has characterized 15 SMA reference materials derived from publicly available cell lines. DNA samples were distributed to four volunteer testing laboratories for genotyping using three different methods. The characterized samples had zero to four copies of SMN1 and zero to five copies SMN2. The samples also contained clinically important allele combinations (eg, zero copies SMN1, three copies SMN2), and several had markers indicative of an SMA carrier. These and other reference materials characterized by the Genetic Testing Reference Materials Coordination Program are available from the Coriell Institute and are proposed to support the quality of clinical laboratory testing.
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http://dx.doi.org/10.1016/j.jmoldx.2020.10.011DOI Listing
January 2021

Cytogenetic and molecular diagnostic testing associated with prenatal and postnatal birth defects.

Birth Defects Res 2020 03;112(4):293-306

Center for Human Genetics, University Hospitals Cleveland Medical Center, Cleveland, Ohio.

Genetic testing is beneficial for patients and providers when in search of answers to medical problems related to the prenatal or early postnatal period. It can help to identify the cause or confirm a diagnosis associated with developmental delay, intellectual disability, dysmorphic features, heart defects, multiple malformations, short stature, stillbirth, neonatal death, or fertility problems. Genetic testing can be used to rule out single-gene or chromosome abnormalities. Different diagnostic cytogenetic and molecular genetic techniques are applied in clinical genetics laboratories, from conventional ones to the state of the art chromosomal microarrays and next-generation sequencing. Each of the genetic techniques or methods has its strengths and limitations, however different methods complement each-other in trying to identify the genetic variation(s) responsible for a medical condition, especially the ones related to birth defects.
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http://dx.doi.org/10.1002/bdr2.1648DOI Listing
March 2020

A case report of genetic prion disease with two different PRNP variants.

Mol Genet Genomic Med 2020 03 17;8(3):e1134. Epub 2020 Jan 17.

National Prion Disease Pathology Surveillance Center, Case Western Reserve University, Cleveland, OH, USA.

Background: Prion diseases are a group of lethal neurodegenerative conditions that occur when the normal, cellular form of the prion protein (PrP ) is converted into an abnormal, scrapie, form of the protein (PrP ). Disease may be caused by genetic, infectious, or sporadic etiologies. The genetic form of prion disease comprises~10%-15% of all cases. Prion disease is typically inherited in an autosomal dominant manner. The low incidence of disease makes it highly unlikely that a patient would have two different pathogenic variants. However, we recently identified a case in which the patient did have two pathogenic PRNP variants and presented with an atypical phenotype.

Methods: The patient was evaluated at the Washington Hospital Healthcare System in Fremont, CA. The clinical information for this case report was obtained retrospectively. Variants in the PRNP were identified by polymerase chain reaction (PCR) amplification of exon two of the gene followed by bi-directional sequence analysis. To determine the phase of the identified variants, a restriction enzyme digestion was utilized, followed by sequence analysis of the products. Cerebral spinal fluid (CSF) was analyzed for surrogate markers of prion disease, 14-3-3 and Tau proteins. CSF real-time quaking-induced conversion (RT-QuIC) assays were also performed.

Results: The patient was a compound heterozygote for the well-characterized c.628G>A (p.Val210Ile) variant and the rare octapeptide deletion of two repeats [c.202_249del48 (p.P68_Q83del)]. Clinically, the patient presented with an early onset demyelinating peripheral neuropathy, followed by later onset cognitive symptoms.

Conclusion: This presentation is reminiscent of prion protein knockout mice whose predominate symptom, due to complete loss of PrP, was late-onset peripheral neuropathy. To our knowledge this is the first case reported of a patient with prion disease who had two different pathogenic variants in PRNP.
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http://dx.doi.org/10.1002/mgg3.1134DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7057106PMC
March 2020

Impact of NPM1/FLT3-ITD genotypes defined by the 2017 European LeukemiaNet in patients with acute myeloid leukemia.

Blood 2020 01;135(5):371-380

The Ohio State University Comprehensive Cancer Center, Columbus, OH.

Patients with acute myeloid leukemia (AML) harboring FLT3 internal tandem duplications (ITDs) have poor outcomes, in particular AML with a high (≥0.5) mutant/wild-type allelic ratio (AR). The 2017 European LeukemiaNet (ELN) recommendations defined 4 distinct FLT3-ITD genotypes based on the ITD AR and the NPM1 mutational status. In this retrospective exploratory study, we investigated the prognostic and predictive impact of the NPM1/FLT3-ITD genotypes categorized according to the 2017 ELN risk groups in patients randomized within the RATIFY trial, which evaluated the addition of midostaurin to standard chemotherapy. The 4 NPM1/FLT3-ITD genotypes differed significantly with regard to clinical and concurrent genetic features. Complete ELN risk categorization could be done in 318 of 549 trial patients with FLT3-ITD AML. Significant factors for response after 1 or 2 induction cycles were ELN risk group and white blood cell (WBC) counts; treatment with midostaurin had no influence. Overall survival (OS) differed significantly among ELN risk groups, with estimated 5-year OS probabilities of 0.63, 0.43, and 0.33 for favorable-, intermediate-, and adverse-risk groups, respectively (P < .001). A multivariate Cox model for OS using allogeneic hematopoietic cell transplantation (HCT) in first complete remission as a time-dependent variable revealed treatment with midostaurin, allogeneic HCT, ELN favorable-risk group, and lower WBC counts as significant favorable factors. In this model, there was a consistent beneficial effect of midostaurin across ELN risk groups.
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http://dx.doi.org/10.1182/blood.2019002697DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6993016PMC
January 2020

Outcome measures in a cohort of ambulatory adults with spinal muscular atrophy.

Muscle Nerve 2020 02 11;61(2):187-191. Epub 2019 Dec 11.

Department of Neurology, Division of Neuromuscular Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio.

Introduction: With the advent of disease-altering therapies for spinal muscular atrophy (SMA), there is a requirement to better characterize outcome measures, particularly in milder forms of disease.

Methods: Maximal voluntary isometric contraction testing and 6-minute walk test (6MWT) performed in ambulatory SMA adults as part of the SMA-VALIANT trial were analyzed. Test-retest reliability and correlation with other candidate biomarkers and outcomes were investigated.

Results: Maximal voluntary isometric contraction testing and 6MWT showed good test-retest reliability (intraclass correlation coefficient = 0.98 and 0.85, respectively). Maximal voluntary isometric contraction testing and 6MWT demonstrated very strong correlation (r = 0.83, P <. 0001), and each correlated with the SMA Functional Rating Scale (r = 0.7, P < .0001 and r = 0.65, P = .0001, respectively), lean muscle mass (r = 0.68, P < .0001 and r = 0.56, P = .001, respectively), and ulnar compound muscle action potential (r = 0.57, P = .0008 and r = 0.47, P = .008, respectively).

Discussion: Maximal voluntary isometric contraction testing and 6MWT are suitable outcomes for use in ambulatory adults with SMA. Maximal voluntary isometric contraction testing may be preferable because of superior test-retest reliability and closer associations with other outcomes and biomarkers of neuromuscular function.
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http://dx.doi.org/10.1002/mus.26756DOI Listing
February 2020

Age-dependent SMN expression in disease-relevant tissue and implications for SMA treatment.

J Clin Invest 2019 11;129(11):4817-4831

Department of Neuroscience and.

BACKGROUNDSpinal muscular atrophy (SMA) is caused by deficient expression of survival motor neuron (SMN) protein. New SMN-enhancing therapeutics are associated with variable clinical benefits. Limited knowledge of baseline and drug-induced SMN levels in disease-relevant tissues hinders efforts to optimize these treatments.METHODSSMN mRNA and protein levels were quantified in human tissues isolated during expedited autopsies.RESULTSSMN protein expression varied broadly among prenatal control spinal cord samples, but was restricted at relatively low levels in controls and SMA patients after 3 months of life. A 2.3-fold perinatal decrease in median SMN protein levels was not paralleled by comparable changes in SMN mRNA. In tissues isolated from nusinersen-treated SMA patients, antisense oligonucleotide (ASO) concentration and full-length (exon 7 including) SMN2 (SMN2-FL) mRNA level increases were highest in lumbar and thoracic spinal cord. An increased number of cells showed SMN immunolabeling in spinal cord of treated patients, but was not associated with an increase in whole-tissue SMN protein levels.CONCLUSIONSA normally occurring perinatal decrease in whole-tissue SMN protein levels supports efforts to initiate SMN-inducing therapies as soon after birth as possible. Limited ASO distribution to rostral spinal and brain regions in some patients likely limits clinical response of motor units in these regions for those patients. These results have important implications for optimizing treatment of SMA patients and warrant further investigations to enhance bioavailability of intrathecally administered ASOs.FUNDINGSMA Foundation, SMART, NIH (R01-NS096770, R01-NS062869), Ionis Pharmaceuticals, and PTC Therapeutics. Biogen provided support for absolute real-time RT-PCR.
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http://dx.doi.org/10.1172/JCI124120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6819103PMC
November 2019

Impact of Age and Motor Function in a Phase 1/2A Study of Infants With SMA Type 1 Receiving Single-Dose Gene Replacement Therapy.

Pediatr Neurol 2019 09 13;98:39-45. Epub 2019 May 13.

Center for Gene Therapy at the Research Institute at Nationwide Children's Hospital, Columbus, Ohio; Department of Pediatrics, Ohio State University, Columbus, Ohio; Department of Neurology, Ohio State University, Columbus, Ohio.

Background: This study characterizes motor function responses after early dosing of AVXS-101 (onasemnogene abeparvovec) in gene replacement therapy in infants with severe spinal muscular atrophy type 1 (SMA1).

Methods: This study is a follow-up analysis of 12 infants with SMA1 who received the proposed therapeutic dose of AVXS-101 in a Phase 1 open-label study (NCT02122952). Infants were grouped according to age at dosing and baseline Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders scores: (1) early dosing/low motor, dosed age less than three months with scores <20 (n = 3), (2) late dosing, dosed at age three months or greater (n = 6), and (3) early dosing/high motor, dosed age less than three months with scores ≥20 (n = 3).

Results: Early dosing/low motor group demonstrated a mean gain of 35.0 points from a mean baseline of 15.7, whereas the late dosing group had a mean gain of 23.3 from a mean baseline of 26.5. The early dosing/high motor group quickly reached a mean score of 60.3, near the scale maximum (64), from a mean baseline of 44.0. Despite a lower baseline motor score, the early dosing/low motor group achieved sitting unassisted earlier than the late dosing group (mean age: 17.0 vs 22.0 months). The early dosing/high motor group reached this milestone earliest (mean age: 9.4 months).

Conclusions: The rapid, significant motor improvements among infants with severe SMA1 treated with AVXS-101 at an early age highlight the importance of newborn screening and early treatment and demonstrate the therapeutic potential of AVXS-101 regardless of baseline motor function.
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http://dx.doi.org/10.1016/j.pediatrneurol.2019.05.005DOI Listing
September 2019

Complete sequencing of the SMN2 gene in SMA patients detects SMN gene deletion junctions and variants in SMN2 that modify the SMA phenotype.

Hum Genet 2019 Mar 20;138(3):241-256. Epub 2019 Feb 20.

Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, USA.

Spinal muscular atrophy (SMA) is a progressive motor neuron disease caused by loss or mutation of the survival motor neuron 1 (SMN1) gene and retention of SMN2. We performed targeted capture and sequencing of the SMN2, CFTR, and PLS3 genes in 217 SMA patients. We identified a 6.3 kilobase deletion that occurred in both SMN1 and SMN2 (SMN1/2) and removed exons 7 and 8. The deletion junction was flanked by a 21 bp repeat that occurred 15 times in the SMN1/2 gene. We screened for its presence in 466 individuals with the known SMN1 and SMN2 copy numbers. In individuals with 1 SMN1 and 0 SMN2 copies, the deletion occurred in 63% of cases. We modeled the deletion junction frequency and determined that the deletion occurred in both SMN1 and SMN2. We have identified the first deletion junction where the deletion removes exons 7 and 8 of SMN1/2. As it occurred in SMN1, it is a pathogenic mutation. We called variants in the PLS3 and SMN2 genes, and tested for association with mild or severe exception patients. The variants A-44G, A-549G, and C-1897T in intron 6 of SMN2 were significantly associated with mild exception patients, but no PLS3 variants correlated with severity. The variants occurred in 14 out of 58 of our mild exception patients, indicating that mild exception patients with an intact SMN2 gene and without modifying variants occur. This sample set can be used in the association analysis of candidate genes outside of SMN2 that modify the SMA phenotype.
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http://dx.doi.org/10.1007/s00439-019-01983-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6503527PMC
March 2019

Natural history of infantile-onset spinal muscular atrophy.

Ann Neurol 2017 Dec 8;82(6):883-891. Epub 2017 Dec 8.

Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH.

Objective: Infantile-onset spinal muscular atrophy (SMA) is the most common genetic cause of infant mortality, typically resulting in death preceding age 2. Clinical trials in this population require an understanding of disease progression and identification of meaningful biomarkers to hasten therapeutic development and predict outcomes.

Methods: A longitudinal, multicenter, prospective natural history study enrolled 26 SMA infants and 27 control infants aged <6 months. Recruitment occurred at 14 centers over 21 months within the NINDS-sponsored NeuroNEXT (National Network for Excellence in Neuroscience Clinical Trials) Network. Infant motor function scales (Test of Infant Motor Performance Screening Items [TIMPSI], The Children's Hospital of Philadelphia Infant Test for Neuromuscular Disorders, and Alberta Infant Motor Score) and putative physiological and molecular biomarkers were assessed preceding age 6 months and at 6, 9, 12, 18, and 24 months with progression, correlations between motor function and biomarkers, and hazard ratios analyzed.

Results: Motor function scores (MFS) and compound muscle action potential (CMAP) decreased rapidly in SMA infants, whereas MFS in all healthy infants rapidly increased. Correlations were identified between TIMPSI and CMAP in SMA infants. TIMPSI at first study visit was associated with risk of combined endpoint of death or permanent invasive ventilation in SMA infants. Post-hoc analysis of survival to combined endpoint in SMA infants with 2 copies of SMN2 indicated a median age of 8 months at death (95% confidence interval, 6, 17).

Interpretation: These data of SMA and control outcome measures delineates meaningful change in clinical trials in infantile-onset SMA. The power and utility of NeuroNEXT to provide "real-world," prospective natural history data sets to accelerate public and private drug development programs for rare disease is demonstrated. Ann Neurol 2017;82:883-891.
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http://dx.doi.org/10.1002/ana.25101DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5776712PMC
December 2017

Single-Dose Gene-Replacement Therapy for Spinal Muscular Atrophy.

N Engl J Med 2017 11;377(18):1713-1722

From the Center for Gene Therapy at the Research Institute at Nationwide Children's Hospital (J.R.M., S.A.-Z., L.R.R.-K., L.L., L.A., K.B., K.C., S.L., C.M., K.M., B.K.K.) and the Departments of Pediatrics (J.R.M., S.A.-Z., R.S., L.L., L.A., K.B., K.C., J.T.K., B.K.K.), Neurology (J.R.M., W.D.A., L.R.R.-K., A.H.M.B., B.K.K.), Pathology (T.W.P.), and Molecular and Cellular Biochemistry (A.H.M.B.), Ohio State University - both in Columbus; and AveXis, Bannockburn, IL (S.N., J.L., D.M.S., C.W., J.A.C., M.D.H., A.K., S.C., L.B., K.D.F., B.K.K.).

Background: Spinal muscular atrophy type 1 (SMA1) is a progressive, monogenic motor neuron disease with an onset during infancy that results in failure to achieve motor milestones and in death or the need for mechanical ventilation by 2 years of age. We studied functional replacement of the mutated gene encoding survival motor neuron 1 (SMN1) in this disease.

Methods: Fifteen patients with SMA1 received a single dose of intravenous adeno-associated virus serotype 9 carrying SMN complementary DNA encoding the missing SMN protein. Three of the patients received a low dose (6.7×10 vg per kilogram of body weight), and 12 received a high dose (2.0×10 vg per kilogram). The primary outcome was safety. The secondary outcome was the time until death or the need for permanent ventilatory assistance. In exploratory analyses, we compared scores on the CHOP INTEND (Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders) scale of motor function (ranging from 0 to 64, with higher scores indicating better function) in the two cohorts and motor milestones in the high-dose cohort with scores in studies of the natural history of the disease (historical cohorts).

Results: As of the data cutoff on August 7, 2017, all 15 patients were alive and event-free at 20 months of age, as compared with a rate of survival of 8% in a historical cohort. In the high-dose cohort, a rapid increase from baseline in the score on the CHOP INTEND scale followed gene delivery, with an increase of 9.8 points at 1 month and 15.4 points at 3 months, as compared with a decline in this score in a historical cohort. Of the 12 patients who had received the high dose, 11 sat unassisted, 9 rolled over, 11 fed orally and could speak, and 2 walked independently. Elevated serum aminotransferase levels occurred in 4 patients and were attenuated by prednisolone.

Conclusions: In patients with SMA1, a single intravenous infusion of adeno-associated viral vector containing DNA coding for SMN resulted in longer survival, superior achievement of motor milestones, and better motor function than in historical cohorts. Further studies are necessary to confirm the safety and efficacy of this gene therapy. (Funded by AveXis and others; ClinicalTrials.gov number, NCT02122952 .).
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http://dx.doi.org/10.1056/NEJMoa1706198DOI Listing
November 2017

Clinical trial of L-Carnitine and valproic acid in spinal muscular atrophy type I.

Muscle Nerve 2018 02 18;57(2):193-199. Epub 2017 Sep 18.

Department of Neurology, Center for Genomic Medicine, Massachusetts General Hospital, 185 Cambridge Street, Simches 5-240, Boston, Massachusetts, 02114, USA.

Introduction: The aim of this study was to determine the safety and therapeutic potential of L-carnitine and valproic acid (VPA) in infants with spinal muscular atrophy (SMA).

Methods: Our investigation was an open-label phase 2 multicenter trial of L-carnitine and VPA in infants with SMA type I with retrospective comparison to an untreated, matched cohort. Primary outcomes were: safety and adverse events; secondary outcomes were survival, time to death/>16 hours/day of ventilator support; motor outcomes; and maximum ulnar compound motor action potential amplitude.

Results: A total of 245 AEs were observed in 35 of the 37 treated subjects (95%). Respiratory events accounted for 49% of all adverse events, resulting in 14 deaths. Survival was not significantly different between treated and untreated cohorts.

Discussion: This trial provides evidence that, in infants with SMA type I, L-carnitine/VPA is ineffective at altering survival. The substantial proportion of infants reaching end-points within 6 months of enrollment underscores the urgent need for pre-symptomatic treatment in SMA type I. Muscle Nerve 57: 193-199, 2018.
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http://dx.doi.org/10.1002/mus.25776DOI Listing
February 2018

Midostaurin plus Chemotherapy for Acute Myeloid Leukemia with a FLT3 Mutation.

N Engl J Med 2017 08 23;377(5):454-464. Epub 2017 Jun 23.

From the Department of Medical Oncology, Dana-Farber Cancer Institute, Boston (R.M.S.); the Division of Biomedical Statistics and Informatics (S.J.M., K.L.) and the Alliance Statistics and Data Center (S.J.M., K.L., S.G.), Mayo Clinic, Rochester, MN; the Alliance Statistics and Data Center, Duke University, Durham, NC (B.L.S.); the Ohio State University Comprehensive Cancer Center, Columbus (S.G., C.D.B., T.W.P., G.M., R.B.K.); Medizinische Klinik und Poliklinik I, Universitätsklinikum Carl Gustav Carus der TU Dresden, Dresden (C.T., G.E.), Department of Internal Medicine III, University Hospital of Ulm, Ulm (K.D., R.F.S., H.D.), Hematology and Oncology, University of Leipzig, Leipzig (D.N.), Department of Hematology, Hemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover (J.K., A.G.), and Department of Medicine II, Hematology-Oncology, Goethe University Hospital Frankfurt, Frankfurt am Main (H.S.) - all in Germany; the Department of Biomedicine and Prevention, University Tor Vergata, Rome (F.L.-C., S.A.); the Department of Clinical Haematology, Alfred Hospital and Monash University, Melbourne, VIC, Australia (A.W.); Hospital de la Santa Creu i Sant Pau, Hematology Department, Autonomous University of Barcelona, Barcelona (J.S.), and Hospital Universitario la Fe, Hematology Department, Department of Medicine, University of Valencia, Valencia (M.A.S.) - both in Spain; the Department of Medical Oncology and Hematology, Princess Margaret Hospital, Toronto (J.M.B.); Radboud Institute Molecular Studies, Radboud University Medical Center, Nijmegen, the Netherlands (T.W.); the Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle (F.R.A.); the Division of Hematology-Oncology, Stanford Comprehensive Cancer Center, Stanford University, Stanford, CA (B.C.M.); the Leukemia Service, Department of Medicine, Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College, New York (M.S.T.); and the Department of Medicine, University of Chicago, Chicago (R.A.L.).

Background: Patients with acute myeloid leukemia (AML) and a FLT3 mutation have poor outcomes. We conducted a phase 3 trial to determine whether the addition of midostaurin - an oral multitargeted kinase inhibitor that is active in patients with a FLT3 mutation - to standard chemotherapy would prolong overall survival in this population.

Methods: We screened 3277 patients, 18 to 59 years of age, who had newly diagnosed AML for FLT3 mutations. Patients were randomly assigned to receive standard chemotherapy (induction therapy with daunorubicin and cytarabine and consolidation therapy with high-dose cytarabine) plus either midostaurin or placebo; those who were in remission after consolidation therapy entered a maintenance phase in which they received either midostaurin or placebo. Randomization was stratified according to subtype of FLT3 mutation: point mutation in the tyrosine kinase domain (TKD) or internal tandem duplication (ITD) mutation with either a high ratio (>0.7) or a low ratio (0.05 to 0.7) of mutant to wild-type alleles (ITD [high] and ITD [low], respectively). Allogeneic transplantation was allowed. The primary end point was overall survival.

Results: A total of 717 patients underwent randomization; 360 were assigned to the midostaurin group, and 357 to the placebo group. The FLT3 subtype was ITD (high) in 214 patients, ITD (low) in 341 patients, and TKD in 162 patients. The treatment groups were well balanced with respect to age, race, FLT3 subtype, cytogenetic risk, and blood counts but not with respect to sex (51.7% in the midostaurin group vs. 59.4% in the placebo group were women, P=0.04). Overall survival was significantly longer in the midostaurin group than in the placebo group (hazard ratio for death, 0.78; one-sided P=0.009), as was event-free survival (hazard ratio for event or death, 0.78; one-sided P=0.002). In both the primary analysis and an analysis in which data for patients who underwent transplantation were censored, the benefit of midostaurin was consistent across all FLT3 subtypes. The rate of severe adverse events was similar in the two groups.

Conclusions: The addition of the multitargeted kinase inhibitor midostaurin to standard chemotherapy significantly prolonged overall and event-free survival among patients with AML and a FLT3 mutation. (Funded by the National Cancer Institute and Novartis; ClinicalTrials.gov number, NCT00651261 .).
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http://dx.doi.org/10.1056/NEJMoa1614359DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5754190PMC
August 2017

A-44G transition in SMN2 intron 6 protects patients with spinal muscular atrophy.

Hum Mol Genet 2017 07;26(14):2768-2780

Department of Pathology, Ohio State University, Columbus, OH 43210, USA.

Spinal muscular atrophy (SMA) is a neuromuscular disease caused by reduced expression of survival of motor neuron (SMN), a protein expressed in humans by two paralogous genes, SMN1 and SMN2. These genes are nearly identical, except for 10 single-nucleotide differences and a 5-nucleotide insertion in SMN2. SMA is subdivided into four main types, with type I being the most severe. SMN2 copy number is a key positive modifier of the disease, but it is not always inversely correlated with clinical severity. We previously reported the c.859G > C variant in SMN2 exon 7 as a positive modifier in several patients. We have now identified A-44G as an additional positive disease modifier, present in a group of patients carrying 3 SMN2 copies but displaying milder clinical phenotypes than other patients with the same SMN2 copy number. One of the three SMN2 copies appears to have been converted from SMN1, but except for the C6T transition, no other changes were detected. Analyzed with minigenes, SMN1C6T displayed a ∼20% increase in exon 7 inclusion, compared to SMN2. Through systematic mutagenesis, we found that the improvement in exon 7 splicing is mainly attributable to the A-44G transition in intron 6. Using RNA-affinity chromatography and mass spectrometry, we further uncovered binding of the RNA-binding protein HuR to the -44 region, where it acts as a splicing repressor. The A-44G change markedly decreases the binding affinity of HuR, resulting in a moderate increase in exon 7 inclusion.
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http://dx.doi.org/10.1093/hmg/ddx166DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5886194PMC
July 2017

Variable phenotypic expression and onset in MYH14 distal hereditary motor neuropathy phenotype in a large, multigenerational North American family.

Muscle Nerve 2017 08 20;56(2):341-345. Epub 2017 Feb 20.

Department of Neurology, Division of Neuromuscular Medicine, The Ohio State University Wexner Medical Center, 395 West 12th Avenue, Columbus, Ohio, 43210, USA.

Introduction: Distal hereditary motor neuropathy (dHMN) causes distal-predominant weakness without prominent sensory loss. Myosin heavy chain disorders most commonly result in distal myopathy and cardiomyopathy with or without hearing loss, but a complex phenotype with dHMN, myopathy, hoarseness, and hearing loss was reported in a Korean family with a c.2822G>T mutation in MYH14. In this study we report phenotypic features in a North American family with the c.2822G>T in MYH14.

Methods: Clinical and molecular characterization was performed in a large, 6-generation, Caucasian family with MYH14 dHMN.

Results: A total of 11 affected and 7 unaffected individuals were evaluated and showed varying age of onset and severity of weakness. Genotypic concordance was confirmed with molecular analysis. Electrophysiological studies demonstrated distal motor axonal degeneration without myopathy in all affected subjects tested.

Conclusion: Mutation of MYH14 can result in a range of neuromuscular phenotypes that includes a dHMN and hearing loss phenotype with variable age of onset. Muscle Nerve 56: 341-345, 2017.
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http://dx.doi.org/10.1002/mus.25491DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5440221PMC
August 2017

Serum versus Imaging Biomarkers in Friedreich Ataxia to Indicate Left Ventricular Remodeling and Outcomes.

Tex Heart Inst J 2016 Aug 1;43(4):305-10. Epub 2016 Aug 1.

Patients with Friedreich ataxia typically die of cardiomyopathy, marked by myocardial fibrosis and abnormal left ventricular (LV) geometry. We measured procollagen I carboxyterminal propeptide (PICP), a serum biomarker of collagen production, and characterized genotypes, phenotypes, and outcomes in these patients. Twenty-nine patients with Friedreich ataxia (mean age, 34.2 ± 2.2 yr) and 29 healthy subjects (mean age, 32.5 ± 1.1 yr) underwent serum PICP measurements. Patients underwent cardiac magnetic resonance imaging and outcome evaluations at baseline and 12 months. Baseline PICP values were significantly higher in the patients than in the control group (1,048 ± 77 vs 614 ± 23 ng/mL; P <0.001); severity of genetic abnormality did not indicate severity of PICP elevation. Higher PICP levels corresponded to greater LV concentric remodeling only at baseline (r=0.37, P <0.05). Higher baseline PICP strongly indicated subsequent increases in LV end-diastolic volume (r=0.52, P=0.02). The PICP levels did not distinguish between 14 patients with evident myocardial fibrosis identified through positive late gadolinium enhancement and 15 who had no enhancement (1,067 ± 125 vs 1,030 ± 98 ng/mL; P=0.82). At 12 months, cardiac events had occurred in 3 of 14 fibrosis-positive and none of 15 fibrosis-negative patients (P=0.1); their baseline PICP levels were similar. We conclude that PICP, a serum marker of collagen synthesis, is elevated in Friedreich ataxia and indicates baseline abnormal LV geometry and subsequent dilation. Cardiac magnetic resonance and PICP warrant consideration as complementary biomarkers in therapeutic trials of Friedreich ataxia cardiomyopathy.
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http://dx.doi.org/10.14503/THIJ-14-4198DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4979385PMC
August 2016

SMN Protein Can Be Reliably Measured in Whole Blood with an Electrochemiluminescence (ECL) Immunoassay: Implications for Clinical Trials.

PLoS One 2016 8;11(3):e0150640. Epub 2016 Mar 8.

Spinal Muscular Atrophy Foundation, New York, New York, United States of America.

Spinal muscular atrophy (SMA) is caused by defects in the survival motor neuron 1 (SMN1) gene that encodes survival motor neuron (SMN) protein. The majority of therapeutic approaches currently in clinical development for SMA aim to increase SMN protein expression and there is a need for sensitive methods able to quantify increases in SMN protein levels in accessible tissues. We have developed a sensitive electrochemiluminescence (ECL)-based immunoassay for measuring SMN protein in whole blood with a minimum volume requirement of 5μL. The SMN-ECL immunoassay enables accurate measurement of SMN in whole blood and other tissues. Using the assay, we measured SMN protein in whole blood from SMA patients and healthy controls and found that SMN protein levels were associated with SMN2 copy number and were greater in SMA patients with 4 copies, relative to those with 2 and 3 copies. SMN protein levels did not vary significantly in healthy individuals over a four-week period and were not affected by circadian rhythms. Almost half of the SMN protein was found in platelets. We show that SMN protein levels in C/C-allele mice, which model a mild form of SMA, were high in neonatal stage, decreased in the first few weeks after birth, and then remained stable throughout the adult stage. Importantly, SMN protein levels in the CNS correlated with SMN levels measured in whole blood of the C/C-allele mice. These findings have implications for the measurement of SMN protein induction in whole blood in response to SMN-upregulating therapy.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0150640PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4783032PMC
August 2016

Baseline results of the NeuroNEXT spinal muscular atrophy infant biomarker study.

Ann Clin Transl Neurol 2016 02 21;3(2):132-45. Epub 2016 Jan 21.

Department of Neurology The Ohio State University Wexner Medical Center Columbus Ohio.

Objective: This study prospectively assessed putative promising biomarkers for use in assessing infants with spinal muscular atrophy (SMA).

Methods: This prospective, multi-center natural history study targeted the enrollment of SMA infants and healthy control infants less than 6 months of age. Recruitment occurred at 14 centers within the NINDS National Network for Excellence in Neuroscience Clinical Trials (NeuroNEXT) Network. Infant motor function scales and putative electrophysiological, protein and molecular biomarkers were assessed at baseline and subsequent visits.

Results: Enrollment began November, 2012 and ended September, 2014 with 26 SMA infants and 27 healthy infants enrolled. Baseline demographic characteristics of the SMA and control infant cohorts aligned well. Motor function as assessed by the Test for Infant Motor Performance Items (TIMPSI) and the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) revealed significant differences between the SMA and control infants at baseline. Ulnar compound muscle action potential amplitude (CMAP) in SMA infants (1.4 ± 2.2 mV) was significantly reduced compared to controls (5.5 ± 2.0 mV). Electrical impedance myography (EIM) high-frequency reactance slope (Ohms/MHz) was significantly higher in SMA infants than controls SMA infants had lower survival motor neuron (SMN) mRNA levels in blood than controls, and several serum protein analytes were altered between cohorts.

Interpretation: By the time infants were recruited and presented for the baseline visit, SMA infants had reduced motor function compared to controls. Ulnar CMAP, EIM, blood SMN mRNA levels, and serum protein analytes were able to distinguish between cohorts at the enrollment visit.
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http://dx.doi.org/10.1002/acn3.283DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4748311PMC
February 2016

Spinal Muscular Atrophy: Overview of Molecular Diagnostic Approaches.

Curr Protoc Hum Genet 2016 Jan 1;88:9.27.1-9.27.13. Epub 2016 Jan 1.

Integrated Genetics, Laboratory Corporation of America Holdings, Westborough, Massachusetts.

Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disease and the most common genetic cause of infant mortality, affecting ∼1 in 10,000 live births. The disease is characterized by progressive symmetrical muscle weakness resulting from the degeneration and loss of anterior horn cells in the spinal cord and brain stem nuclei. The disease is classified on the basis of age of onset and clinical course. SMA is caused by mutations in the telomeric copy of the survival motor neuron 1 (SMN1) gene, but all patients retain a centromeric copy of the gene, SMN2. The homozygous absence of the SMN1 exon 7 has been observed in the majority of patients and is being utilized as a reliable and sensitive SMA diagnostic test. In the majority of cases, the disease severity correlates inversely with an increased SMN2 gene copy number. Carrier detection, in the deletion cases, relies on the accurate determination of the SMN1 gene copies. Since SMA is one of the most common lethal genetic disorders, with a carrier frequency of 1 in 40 to 1 in 60, direct carrier dosage testing has been beneficial to many families. This unit attempts to highlight the molecular genetics of SMA with a focus on the advantages and limitations of the current molecular technologies.
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http://dx.doi.org/10.1002/0471142905.hg0927s88DOI Listing
January 2016

Spinal Muscular Atrophy Biomarker Measurements from Blood Samples in a Clinical Trial of Valproic Acid in Ambulatory Adults.

J Neuromuscul Dis 2015 Jun;2(2):119-130

Department of Molecular & Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, OH, USA.

Background: Clinical trials of therapies for spinal muscular atrophy (SMA) that are designed to increase the expression the SMN protein ideally include careful assessment of relevant SMN biomarkers.

Objective: In the SMA VALIANT trial, a recent double-blind placebo-controlled crossover study of valproic acid (VPA) in ambulatory adult subjects with SMA, we investigated relevant pharmacodynamic biomarkers in blood samples from SMA subjects by direct longitudinal measurement of histone acetylation and SMN mRNA and protein levels in the presence and absence of VPA treatment.

Methods: Thirty-three subjects were randomized to either VPA or placebo for the first 6 months followed by crossover to the opposite arm for an additional 6 months. Outcome measures were compared between the two treatments (VPA and placebo) using a standard crossover analysis.

Results: A significant increase in histone H4 acetylation was observed with VPA treatment (p = 0.005). There was insufficient evidence to suggest a treatment effect with either full length or truncated SMN mRNA transcript levels or SMN protein levels.

Conclusions: These measures were consistent with the observed lack of change in the primary clinical outcome measure in the VALIANT trial. These results also highlight the added benefit of molecular and pharmacodynamic biomarker measurements in the interpretation of clinical trial outcomes.
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http://dx.doi.org/10.3233/JND-150081DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5271431PMC
June 2015

Duchenne muscular dystrophy diagnostics: it only gets better but some of the same challenges remain.

Authors:
Thomas W Prior

Clin Chem 2015 Jun 7;61(6):792-3. Epub 2015 Apr 7.

Department of Pathology, The Ohio State University, Columbus, OH.

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http://dx.doi.org/10.1373/clinchem.2015.240697DOI Listing
June 2015

Next-generation carrier screening: are we ready?

Authors:
Thomas W Prior

Genome Med 2014 26;6(8):62. Epub 2014 Aug 26.

Department of Pathology, Ohio State University, Neil Avenue, Columbus, OH 43210 USA.

Next-generation sequencing (NGS) methodology allows for a major expansion in current carrier screening tests. NGS testing has been shown to be analytically accurate and cost-effective, but major challenges include educational and counseling issues.
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http://dx.doi.org/10.1186/s13073-014-0062-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4254436PMC
December 2014

Congenital lethal motor neuron disease with a novel defect in ribosome biogenesis.

Neurology 2014 Apr 19;82(15):1322-30. Epub 2014 Mar 19.

From the Departments of Neurology (R.J.B., T.M.N., J.L.B., K.J.S.) and Pediatrics (R.J.B., T.J.S., L.X., J.L.B., K.J.S.), Pediatric Motor Disorders Research Program (R.J.B., T.M.N., B.N., K.J.S.), and Interdepartmental Program in Neurosciences (L.X.), University of Utah School of Medicine, Salt Lake City, UT; Ambry Genetics (W.Z., X.L., H-M.L., H.L., K.D.F.G., J-P.W., E.C.C., P.J.S.), Aliso Viejo, CA; Division of Genetics & Metabolism (E.C.C.), University of California, Irvine; and Department of Molecular Pathology (T.W.P.), Ohio State University, Columbus.

Objective: We describe a novel congenital motor neuron disease with early demise due to respiratory insufficiency with clinical overlap with spinal muscular atrophy with respiratory distress (SMARD) type 1 but lacking a mutation in the IGHMBP2 gene.

Methods: Exome sequencing was used to identify a de novo mutation in the LAS1L gene in the proband. Pathogenicity of the mutation was validated using a zebrafish model by morpholino-mediated knockdown of las1l.

Results: We identified a de novo mutation in the X-linked LAS1L gene in the proband (p.S477N). The mutation is in a highly conserved region of the LAS1L gene predicted to be deleterious by bioinformatic analysis. Morpholino-based knockdown of las1l, the orthologous gene in zebrafish, results in early lethality and disruption of muscle and peripheral nerve architecture. Coinjection of wild-type but not mutant human RNA results in partial rescue of the phenotype.

Conclusion: We report a patient with a SMARD phenotype due to a mutation in LAS1L, a gene important in coordinating processing of the 45S pre-rRNA and maturation of the large 60S ribosomal subunit. Similarly, the IGHMB2 gene associated with SMARD type 1 has been suggested to have an important role in ribosomal biogenesis from its role in processing the 45S pre-rRNA. We propose that disruption of ribosomal maturation may be a common pathogenic mechanism linking SMARD phenotypes caused by both IGHMBP2 and LAS1L.
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http://dx.doi.org/10.1212/WNL.0000000000000305DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4001186PMC
April 2014

Suppression of severe achondroplasia with developmental delay and acanthosis nigricans by the p.Thr651Pro mutation.

Am J Med Genet A 2014 Jan 29;164A(1):243-50. Epub 2013 Oct 29.

Section of Human and Molecular Genetics, Nationwide Children's Hospital, Columbus, Ohio.

Severe achondroplasia with developmental delay and acanthosis nigricans (SADDAN) is an extremely rare severe skeletal dysplasia characterized by significant developmental delay, brain structural abnormalities, hearing loss, and acanthosis nigricans. The disorder is the result of a single missense mutation at codon 650 (p.Lys650Met) in the fibroblast growth factor receptor 3 gene (FGFR3). We describe a child who initially presented with a mild achondroplasia or hypochondroplasia like phenotype. Molecular analysis of the FGFR3 gene showed the common SADDAN mutation and a second novel mutation at codon 651 (p.Thr651Pro). Both mutations were shown to occur on the same allele (cis) and de novo. Transient transfection studies with FGFR3 double mutant constructs show that the p.Thr651Pro mutation causes a dramatic decrease in constitutive receptor kinase activity than that observed by the p.Lys650Met mutation. Our data suggest that the molecular effect by the p.Thr651Pro is to elicit a conformational change that decreases the FGFR3 tyrosine kinase activity, which is constitutively activated by the SADDAN mutation. Due to the inheritance of both a gain-of-function and a loss-of-function mutation, we conclude that a reduction of constitutive activation caused the milder skeletal phenotype. Although the occurrence of double mutations are expected to be rare, the presence of other FGFR3 modifiers may be responsible for some of the clinically discrepant skeletal dysplasia cases.
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http://dx.doi.org/10.1002/ajmg.a.36236DOI Listing
January 2014

Duplication of the Xq27.3-q28 region, including the FMR1 gene, in an X-linked hypogonadism, gynecomastia, intellectual disability, short stature, and obesity syndrome.

Am J Med Genet A 2013 Sep 29;161A(9):2294-9. Epub 2013 Jul 29.

Section of Human and Molecular Genetics, Nationwide Children's Hospital, Columbus, Ohio, USA.

In 1979 a "new" syndrome characterized by X-linked inheritance, hypogonadism, gynecomastia, intellectual disability, obesity, and short stature was described. The now-36-year-old propositus was recently referred to the genetics clinic for profound intellectual disability. Fragile X testing initially demonstrated a duplication of the FMR1 region, and upon further testing we identified an Xq27.3-q28 8.05 Mb-long duplication responsible for a syndrome. Our report describes the molecular and clinical aspects of the X-linked syndrome. Our results suggest that male patients with intellectual disability, hypogonadism, short stature, and gynecomastia should be further investigated for rearrangements in the Xq27.3-q28 region. In the future, when more cases of the duplication are identified, it may become possible to more accurately determine the specific genes affected by overexpression and responsible for the phenotype.
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http://dx.doi.org/10.1002/ajmg.a.36034DOI Listing
September 2013

SMA valiant trial: a prospective, double-blind, placebo-controlled trial of valproic acid in ambulatory adults with spinal muscular atrophy.

Muscle Nerve 2014 Feb;49(2):187-92

Introduction: An open-label trial suggested that valproic acid (VPA) improved strength in adults with spinal muscular atrophy (SMA). We report a 12-month, double-blind, cross-over study of VPA in ambulatory SMA adults.

Methods: There were 33 subjects, aged 20–55 years, included in this investigation. After baseline assessment, subjects were randomized to receive VPA (10–20 mg/kg/day) or placebo. At 6 months, patients were switched to the other group. Assessments were performed at 3, 6, and 12 months. The primary outcome was the 6-month change in maximum voluntary isometric contraction testing with pulmonary, electrophysiological, and functional secondary outcomes.

Results: Thirty subjects completed the study. VPA was well tolerated, and compliance was good. There was no change in primary or secondary outcomes at 6 or 12 months.

Conclusions: VPA did not improve strength or function in SMA adults. The outcomes used are feasible and reliable and can be employed in future trials in SMA adults.
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http://dx.doi.org/10.1002/mus.23904DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3888833PMC
February 2014

inv(16)/t(16;16) acute myeloid leukemia with non-type A CBFB-MYH11 fusions associate with distinct clinical and genetic features and lack KIT mutations.

Blood 2013 Jan 16;121(2):385-91. Epub 2012 Nov 16.

The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA.

The inv(16)(p13q22)/t(16;16)(p13;q22) in acute myeloid leukemia results in multiple CBFB-MYH11 fusion transcripts, with type A being most frequent. The biologic and prognostic implications of different fusions are unclear. We analyzed CBFB-MYH11 fusion types in 208 inv(16)/t(16;16) patients with de novo disease, and compared clinical and cytogenetic features and the KIT mutation status between type A (n = 182; 87%) and non-type A (n = 26; 13%) patients. At diagnosis, non-type A patients had lower white blood counts (P = .007), and more often trisomies of chromosomes 8 (P = .01) and 21 (P < .001) and less often trisomy 22 (P = .02). No patient with non-type A fusion carried a KIT mutation, whereas 27% of type A patients did (P = .002). Among the latter, KIT mutations conferred adverse prognosis; clinical outcomes of non-type A and type A patients with wild-type KIT were similar. We also derived a fusion-type-associated global gene-expression profile. Gene Ontology analysis of the differentially expressed genes revealed-among others-an enrichment of up-regulated genes involved in activation of caspase activity, cell differentiation and cell cycle control in non-type A patients. We conclude that non-type A fusions associate with distinct clinical and genetic features, including lack of KIT mutations, and a unique gene-expression profile.
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http://dx.doi.org/10.1182/blood-2012-07-442772DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3544117PMC
January 2013

Newborn screening for spinal muscular atrophy by calibrated short-amplicon melt profiling.

Clin Chem 2012 Jun 9;58(6):1033-9. Epub 2012 Apr 9.

Department of Pathology, Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.

Background: The management options for the autosomal recessive neurodegenerative disorder spinal muscular atrophy (SMA) are evolving; however, their efficacy may require presymptom diagnosis and continuous treatment. To identify presymptomatic SMA patients, we created a DNA-based newborn screening assay to identify the homozygous deletions of the SMN1 (survival of motor neuron 1, telomeric) gene observed in 95%-98% of affected patients.

Methods: We developed primers that amplify a 52-bp PCR product from homologous regions in the SMN1 and SMN2 (survival of motor neuron 2, centromeric) genes that flank a divergent site at site c.840. Post-PCR high-resolution melt profiling assessed the amplification product, and we used a unique means of melt calibration to normalize profiles. Samples that we had previously characterized for the numbers of SMN1 and SMN2 copies established genotypes associated with particular profiles. The system was evaluated with approximately 1000 purified DNA samples, 100 self-created dried blood spots, and >1200 dried blood spots from newborn screening tests.

Results: Homozygous deletion of SMN1 exon 7 produced a distinctive melt profile that identified SMA patients. Samples with different numbers of SMN1 and SMN2 copies were resolved by their profiles. All samples with homozygous deletions were unambiguously recognized, and no normal sample was misidentified as a positive.

Conclusions: This assay has characteristics suitable for population-based screening. A reliable screening test will facilitate the identification of an SMA-affected cohort to receive early intervention to maximize the benefit from treatment. A prospective screening trial will allow the efficacy of treatment options to be assessed, which may justify the inclusion of SMA as a target for population screening.
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http://dx.doi.org/10.1373/clinchem.2012.183038DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4334578PMC
June 2012