Publications by authors named "Jenny Thies"

19 Publications

  • Page 1 of 1

Delineating the molecular and phenotypic spectrum of the SETD1B-related syndrome.

Genet Med 2021 Aug 3. Epub 2021 Aug 3.

Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK.

Purpose: Pathogenic variants in SETD1B have been associated with a syndromic neurodevelopmental disorder including intellectual disability, language delay, and seizures. To date, clinical features have been described for 11 patients with (likely) pathogenic SETD1B sequence variants. This study aims to further delineate the spectrum of the SETD1B-related syndrome based on characterizing an expanded patient cohort.

Methods: We perform an in-depth clinical characterization of a cohort of 36 unpublished individuals with SETD1B sequence variants, describing their molecular and phenotypic spectrum. Selected variants were functionally tested using in vitro and genome-wide methylation assays.

Results: Our data present evidence for a loss-of-function mechanism of SETD1B variants, resulting in a core clinical phenotype of global developmental delay, language delay including regression, intellectual disability, autism and other behavioral issues, and variable epilepsy phenotypes. Developmental delay appeared to precede seizure onset, suggesting SETD1B dysfunction impacts physiological neurodevelopment even in the absence of epileptic activity. Males are significantly overrepresented and more severely affected, and we speculate that sex-linked traits could affect susceptibility to penetrance and the clinical spectrum of SETD1B variants.

Conclusion: Insights from this extensive cohort will facilitate the counseling regarding the molecular and phenotypic landscape of newly diagnosed patients with the SETD1B-related syndrome.
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http://dx.doi.org/10.1038/s41436-021-01246-2DOI Listing
August 2021

The low excretor phenotype of glutaric acidemia type I is a source of false negative newborn screening results and challenging diagnoses.

JIMD Rep 2021 Jul 5;60(1):67-74. Epub 2021 Apr 5.

Biochemical Genetics Laboratory, Mayo Clinic Rochester Minnesota USA.

Background: Glutaric acidemia type I (GA1) is an organic acidemia that is often unrecognized in the newborn period until patients suffer an acute encephalopathic crisis, which can be mistaken for nonaccidental trauma. Presymptomatic identification of GA1 patients is possible by newborn screening (NBS). However, the biochemical "low-excretor" (LE) phenotype with nearly normal levels of disease metabolites can be overlooked, which may result in untreated disease and irreversible neurological sequelae. The LE phenotype is also a potential source of false negative (FN) NBS results that merits further investigation.

Methods: Samples from six LE GA1 patients were analyzed by biochemical and molecular methods and newborn screen outcomes were retrospectively investigated.

Results: Five LE GA1 patients were identified that had normal NBS results and three of these presented clinically with GA1 symptoms. One additional symptomatic patient was identified who did not undergo screening. Semiquantitative urine organic acid analysis was consistent with a GA1 diagnosis in two (33%) of the six patients, while plasma glutarylcarnitine was elevated in four (67%) of the six and urine glutarylcarnitine was elevated in four (80%) of five patients. Five variants were identified in these patients; three of which have not been previously linked to the biochemical LE phenotype.

Conclusions: The data presented here raise awareness of potential FN NBS results for LE GA1 patients. The LE phenotype is not protective against adverse clinical outcomes, and the possibility of FN NBS results calls for high vigilance amongst clinicians, even in the setting of a normal NBS result.
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http://dx.doi.org/10.1002/jmd2.12217DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8260482PMC
July 2021

Targeted long-read sequencing identifies missing disease-causing variation.

Am J Hum Genet 2021 08 2;108(8):1436-1449. Epub 2021 Jul 2.

Department of Pediatrics, Division of Genetic Medicine, University of Washington and Seattle Children's Hospital, Seattle, WA 98105, USA; Center for Clinical and Translational Research, Seattle Children's Research Institute, Seattle, WA 98101, USA.

Despite widespread clinical genetic testing, many individuals with suspected genetic conditions lack a precise diagnosis, limiting their opportunity to take advantage of state-of-the-art treatments. In some cases, testing reveals difficult-to-evaluate structural differences, candidate variants that do not fully explain the phenotype, single pathogenic variants in recessive disorders, or no variants in genes of interest. Thus, there is a need for better tools to identify a precise genetic diagnosis in individuals when conventional testing approaches have been exhausted. We performed targeted long-read sequencing (T-LRS) using adaptive sampling on the Oxford Nanopore platform on 40 individuals, 10 of whom lacked a complete molecular diagnosis. We computationally targeted up to 151 Mbp of sequence per individual and searched for pathogenic substitutions, structural variants, and methylation differences using a single data source. We detected all genomic aberrations-including single-nucleotide variants, copy number changes, repeat expansions, and methylation differences-identified by prior clinical testing. In 8/8 individuals with complex structural rearrangements, T-LRS enabled more precise resolution of the mutation, leading to changes in clinical management in one case. In ten individuals with suspected Mendelian conditions lacking a precise genetic diagnosis, T-LRS identified pathogenic or likely pathogenic variants in six and variants of uncertain significance in two others. T-LRS accurately identifies pathogenic structural variants, resolves complex rearrangements, and identifies Mendelian variants not detected by other technologies. T-LRS represents an efficient and cost-effective strategy to evaluate high-priority genes and regions or complex clinical testing results.
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http://dx.doi.org/10.1016/j.ajhg.2021.06.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8387463PMC
August 2021

Biallelic variants in KARS1 are associated with neurodevelopmental disorders and hearing loss recapitulated by the knockout zebrafish.

Genet Med 2021 Oct 25;23(10):1933-1943. Epub 2021 Jun 25.

Department of Pediatric Diseases, Mashhad University of Medical Sciences, Mashhad, Iran.

Purpose: Pathogenic variants in Lysyl-tRNA synthetase 1 (KARS1) have increasingly been recognized as a cause of early-onset complex neurological phenotypes. To advance the timely diagnosis of KARS1-related disorders, we sought to delineate its phenotype and generate a disease model to understand its function in vivo.

Methods: Through international collaboration, we identified 22 affected individuals from 16 unrelated families harboring biallelic likely pathogenic or pathogenic in KARS1 variants. Sequencing approaches ranged from disease-specific panels to genome sequencing. We generated loss-of-function alleles in zebrafish.

Results: We identify ten new and four known biallelic missense variants in KARS1 presenting with a moderate-to-severe developmental delay, progressive neurological and neurosensory abnormalities, and variable white matter involvement. We describe novel KARS1-associated signs such as autism, hyperactive behavior, pontine hypoplasia, and cerebellar atrophy with prevalent vermian involvement. Loss of kars1 leads to upregulation of p53, tissue-specific apoptosis, and downregulation of neurodevelopmental related genes, recapitulating key tissue-specific disease phenotypes of patients. Inhibition of p53 rescued several defects of kars1 knockouts.

Conclusion: Our work delineates the clinical spectrum associated with KARS1 defects and provides a novel animal model for KARS1-related human diseases revealing p53 signaling components as potential therapeutic targets.
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http://dx.doi.org/10.1038/s41436-021-01239-1DOI Listing
October 2021

Quantitative analysis of the natural history of prolidase deficiency: description of 17 families and systematic review of published cases.

Genet Med 2021 09 26;23(9):1604-1615. Epub 2021 May 26.

Department of Dermatology, University Hospital Münster, Münster, Germany.

Purpose: Prolidase deficiency is a rare inborn error of metabolism causing ulcers and other skin disorders, splenomegaly, developmental delay, and recurrent infections. Most of the literature is constituted of isolated case reports. We aim to provide a quantitative description of the natural history of the condition by describing 19 affected individuals and reviewing the literature.

Methods: Nineteen patients were phenotyped per local institutional procedures. A systematic review following PRISMA criteria identified 132 articles describing 161 patients. Main outcome analyses were performed for manifestation frequency, diagnostic delay, overall survival, symptom-free survival, and ulcer-free survival.

Results: Our cohort presented a wide variability of severity. Autoimmune disorders were found in 6/19, including Crohn disease, systemic lupus erythematosus, and arthritis. Another immune finding was hemophagocytic lymphohistiocytosis (HLH). Half of published patients were symptomatic by age 4 and had a delayed diagnosis (mean delay 11.6 years). Ulcers were present initially in only 30% of cases, with a median age of onset at 12 years old.

Conclusion: Prolidase deficiency has a broad range of manifestations. Symptoms at onset may be nonspecific, likely contributing to the diagnostic delay. Testing for this disorder should be considered in any child with unexplained autoimmunity, lower extremity ulcers, splenomegaly, or HLH.
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http://dx.doi.org/10.1038/s41436-021-01200-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8463480PMC
September 2021

CHRNB1-associated congenital myasthenia syndrome: Expanding the clinical spectrum.

Am J Med Genet A 2021 03 9;185(3):827-835. Epub 2020 Dec 9.

Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, USA.

CHRNB1 encodes the β subunit of the acetylcholine receptor (AChR) at the neuromuscular junction. Inherited defects in the neuromuscular junction can lead to congenital myasthenia syndrome (CMS), a clinically and genetically heterogeneous group of disorders which includes fetal akinesia deformation sequence (FADS) on the severe end of the spectrum. Here, we report two unrelated families with biallelic CHRNB1 variants, and in each family, one child presented with lethal FADS. We contrast the diagnostic odysseys in the two families, one of which lasted 16 years while the other, utilizing rapid exome sequencing, led to specific treatment in the first 2 weeks of life. Furthermore, we note that CHRNB1 variants may be under-recognized because in both families, one of the variants is a single exon deletion that has been previously described but may not easily be detected in clinically available genetic testing.
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http://dx.doi.org/10.1002/ajmg.a.62011DOI Listing
March 2021

Tutorial: Triheptanoin and Nutrition Management for Treatment of Long-Chain Fatty Acid Oxidation Disorders.

JPEN J Parenter Enteral Nutr 2021 02 11;45(2):230-238. Epub 2020 Nov 11.

Department of Pediatrics, Biochemical Genetics, University of Washington, Seattle Children's Hospital, Seattle, Washington, USA.

Background: Patients with severe long-chain fatty acid oxidation disorders (LC-FAODs) experience serious morbidity and mortality despite traditional dietary management including medium-chain triglyceride (MCT)-supplemented, low-fat diets. Triheptanoin is a triglyceride oil that is broken down to acetyl-coenzyme A (CoA) and propionyl-CoA, which replenishes deficient tricarboxylic acid cycle intermediates. We report the complex medical and nutrition management of triheptanoin therapy initiated emergently for 3 patients with LC-FAOD.

Methods: Triheptanoin (Ultragenyx Pharmaceutical, Inc, Novato, CA, USA) was administered to 3 patients with LC-FAOD on a compassionate-use basis. Triheptanoin was mixed with non-MCT-containing low-fat formula. Patients were closely followed with regular cardiac and laboratory monitoring.

Results: Cardiac ejection fraction normalized after triheptanoin initiation. Patients experienced fewer hospitalizations related to metabolic crises while on triheptanoin. Patient 1 has tolerated oral administration without difficulty since birth. Patients 2 and 3 experienced increased diarrhea. Recurrent breakdown of the silicone gastrostomy tube occurred in patient 3, whereas the polyurethane nasogastric tube for patient 2 remained intact. Patient 3 experiences recurrent episodes of elevated creatine kinase levels and muscle weakness associated with illness. Patient 3 had chronically elevated C10-acylcarnitines while on MCT supplementation, which normalized after initiation of triheptanoin and discontinuation of MCT oil.

Conclusions: Triheptanoin can ameliorate acute cardiomyopathy and increase survival in patients with severe LC-FAOD. Substituting triheptanoin for traditional MCT-based treatment improves clinical outcomes. MCT oil might be less effective in carnitine-acylcarnitine translocase deficiency patients compared with other FAODs and needs further investigation.
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http://dx.doi.org/10.1002/jpen.2034DOI Listing
February 2021

Immune dysfunction in MGAT2-CDG: A clinical report and review of the literature.

Am J Med Genet A 2021 01 12;185(1):213-218. Epub 2020 Oct 12.

Department of Pediatrics, School of Medicine, University of Washington, Seattle, Washington, USA.

Glycosylation is a critical post/peri-translational modification required for the appropriate development and function of the immune system. As an example, abnormalities in glycosylation can cause antibody deficiency and reduced lymphocyte signaling, although the phenotype can be complex given the diverse roles of glycosylation. Human MGAT2 encodes N-acetylglucosaminyltransferase II, which is a critical enzyme in the processing of oligomannose to complex N-glycans. Complex N-glycans are essential for immune system functionality, but only one individual with MGAT2-CDG has been described to have an abnormal immunologic evaluation. MGAT2-CDG (CDG-IIa) is a congenital disorder of glycosylation (CDG) associated with profound global developmental disability, hypotonia, early onset epilepsy, and other multisystem manifestations. Here, we report a 4-year old female with MGAT2-CDG due to a novel homozygous pathogenic variant in MGAT2, a 4-base pair deletion, c.1006_1009delGACA. In addition to clinical features previously described in MGAT2-CDG, she experienced episodic asystole, persistent hypogammaglobulinemia, and defective ex vivo mitogen and antigen proliferative responses, but intact specific vaccine antibody titers. Her infection history has been mild despite the testing abnormalities. We compare this patient to the 15 previously reported patients in the literature, thus expanding both the genotypic and phenotypic spectrum for MGAT2-CDG.
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http://dx.doi.org/10.1002/ajmg.a.61914DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8098812PMC
January 2021

p.P1379S, a benign variant with reduced ATP7B protein level in Wilson Disease.

JIMD Rep 2020 Jul 19;54(1):32-36. Epub 2020 May 19.

Seattle Children's Research Institute Seattle Washington USA.

Background: Wilson disease (WD) is an autosomal recessive disorder of copper transport caused by inherited defects in the gene and results in toxic accumulation of copper in various organs. We previously reported a family with three consecutive generations affected by WD that carries the variant, p.P1379S, which was classified at the time as likely pathogenic. However, recent investigations of the p.P1379S variant indicate a possible conflict of interpretations regarding its pathogenicity. This led us to explore the quantification of ATP7B in dried blood spots (DBS) using a surrogate peptide to study the effects of the p.P1379S variant on ATP7B concentrations in two unrelated families with the common p.P1379S variant.

Methods And Results: ATP7B was quantified using the peptide immunoaffinity enrichment coupled with selected reaction monitoring mass spectrometry (immuno-SRM) method which utilizes antibody-mediated peptide capture from DBS. Two patients affected with WD had undetectable ATP7B level while four compound heterozygous children with one known pathogenic variant and the p.P1379S had significantly reduced ATP7B levels. Of note, all four children remain asymptomatic without abnormal laboratory consequences despite being untreated for WD.

Conclusion: These two families demonstrated that p.P1379S, when compounded with two known pathogenic variants, resulted in significantly reduced protein levels but retained enough function to maintain normal copper homeostasis. This implies that p.P1379S is benign in nature. A better understanding of the nature and consequences of variants in WD will help in informing patient care and avoiding unnecessary treatments.
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http://dx.doi.org/10.1002/jmd2.12127DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7358663PMC
July 2020

Clinical Exome Studies Have Inconsistent Coverage.

Clin Chem 2020 01;66(1):199-206

Department of Pathology, Children's Health System of Texas, Dallas, TX.

Background: Exome sequencing has become a commonly used clinical diagnostic test. Multiple studies have examined the diagnostic utility and individual laboratory performance of exome testing; however, no previous study has surveyed and compared the data quality from multiple clinical laboratories.

Methods: We examined sequencing data from 36 clinical exome tests from 3 clinical laboratories. Exome data were compared in terms of overall characteristics and coverage of specific genes and nucleotide positions. The sets of genes examined included genes in Consensus Coding Sequence (CCDS) (n = 17723), a subset of genes clinically relevant to epilepsy (n = 108), and genes that are recommended for reporting of secondary findings (n = 57; excludes X-linked genes).

Results: The average exome nucleotide coverage (≥20×) of each laboratory varied at 96.49% (CV = 3%), 96.54% (CV = 1%), and 91.68% (CV = 4%), for laboratories A, B, and C, respectively. For CCDS genes, the average number of completely covered genes varied at 12184 (CV = 29%), 11687 (CV = 13%), and 5989 (CV = 37%), for laboratories A, B, and C, respectively. With smaller subsets of genes related to epilepsy and secondary findings, the CV revealed low consistency, with a maximum CV seen in laboratory C for both epilepsy genes (CV = 60%) and secondary findings genes (CV = 71%).

Conclusions: Poor consistency in complete gene coverage was seen in the clinical exome laboratories surveyed. The degree of consistency varied widely between the laboratories.
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http://dx.doi.org/10.1093/clinchem.2019.306795DOI Listing
January 2020

The Impact of Rapid Exome Sequencing on Medical Management of Critically Ill Children.

J Pediatr 2020 Jun 15. Epub 2020 Jun 15.

Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA; Division of Genetic Medicine, Seattle Children's Hospital, Seattle, WA; Brotman Baty Institute for Precision Medicine, Seattle, WA; Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA. Electronic address:

Objectives: To evaluate the clinical usefulness of rapid exome sequencing (rES) in critically ill children with likely genetic disease using a standardized process at a single institution. To provide evidence that rES with should become standard of care for this patient population.

Study Design: We implemented a process to provide clinical-grade rES to eligible children at a single institution. Eligibility included (a) recommendation of rES by a consulting geneticist, (b) monogenic disorder suspected, (c) rapid diagnosis predicted to affect inpatient management, (d) pretest counseling provided by an appropriate provider, and (e) unanimous approval by a committee of 4 geneticists. Trio exome sequencing was sent to a reference laboratory that provided verbal report within 7-10 days. Clinical outcomes related to rES were prospectively collected. Input from geneticists, genetic counselors, pathologists, neonatologists, and critical care pediatricians was collected to identify changes in management related to rES.

Results: There were 54 patients who were eligible for rES over a 34-month study period. Of these patients, 46 underwent rES, 24 of whom (52%) had at least 1 change in management related to rES. In 20 patients (43%), a molecular diagnosis was achieved, demonstrating that nondiagnostic exomes could change medical management in some cases. Overall, 84% of patients were under 1 month old at rES request and the mean turnaround time was 9 days.

Conclusions: rES testing has a significant impact on the management of critically ill children with suspected monogenic disease and should be considered standard of care for tertiary institutions who can provide coordinated genetics expertise.
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http://dx.doi.org/10.1016/j.jpeds.2020.06.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7736066PMC
June 2020

The co-occurrence of Wilson disease and X-linked agammaglobulinemia in one family highlights the promising diagnostic potential of proteolytic analysis.

Mol Genet Genomic Med 2020 04 17;8(4):e1172. Epub 2020 Feb 17.

School of Medicine, Department of Pediatrics, University of Washington, Seattle, WA, USA.

Background: We report the first case of a family with co-occurrence of Wilson disease (WD), an autosomal recessive disorder of copper metabolism, and X-linked agammaglobulinemia (XLA), a primary immunodeficiency disorder (PIDD) that features marked reduction in circulating B lymphocytes and serum immunoglobulins.

Methods And Results: Through utilization of a multiplexed biomarker peptide quantification method known as the immuno-SRM assay, we were able to simultaneously and independently identify which family members are affected with WD and which are affected with XLA using dried blood spots (DBS).

Conclusion: Being able to delineate multiple diagnoses using proteolytic analysis from a single DBS provides support for implementation of this methodology for clinical diagnostic use as well as large-scale population screening, such as newborn screening (NBS). This could allow for early identification and treatment of affected individuals with WD or XLA, which have been shown to reduce morbidity and decrease mortality in these two populations.
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http://dx.doi.org/10.1002/mgg3.1172DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7196455PMC
April 2020

Expansion of the Primrose syndrome phenotype through the comparative analysis of two new case reports with ZBTB20 variants.

Am J Med Genet A 2019 11 18;179(11):2228-2232. Epub 2019 Jul 18.

Keizo Asami Laboratory, Universidade Federal de Pernambuco, Recife, Brazil.

Primrose syndrome (PRIMS), a rare genetic disorder with several clinical findings including intellectual disability, macrocephaly, typical facial features, and muscle wasting, is caused by heterozygous variants in the ZBTB20 gene. We report the cases of two males diagnosed with PRIMS at different ages, emphasizing the likely progressive nature of the disorder, as well as the differences and similarities of presentation during infancy and adulthood. Patient 1 is a 2-year-old American male with a medical history marked by impaired hearing, developmental delays, and fainting spells. Patient 2 is a 28-year-old Brazilian male, who presents with a phenotype similar to that seen in Patient 1 with additional features of ectopic calcifications and prominent muscular and skeletal abnormalities. Additionally, Patient 2 has a history of fainting spells and diminished body height and weight, with the latter features having only been reported in one PRIMS patient so far. Both Patients 1 and 2 were found to carry heterozygous likely pathogenic missense variants, detected in the last coding exon of ZBTB20 (c.1822T>C, p.Cys608Arg, de novo, and c.1873A>G, p.Met625Val, respectively), consistent with PRIMS. Overall, these case reports highlight PRIMS's likely progressive nature and contribute to the understanding of the natural history of this condition.
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http://dx.doi.org/10.1002/ajmg.a.61297DOI Listing
November 2019

Rapid clinical exome sequencing in a pediatric ICU: Genetic counselor impacts and challenges.

J Genet Couns 2019 04;28(2):283-291

Department of Laboratories, Seattle Children's Hospital, Seattle, Washington.

Exome sequencing (ES) has revolutionized molecular diagnosis in children with genetic disease over the past decade. However, exome sequencing in the inpatient setting has traditionally been discouraged, in part due to an increased risk of providers failing to retrieve and act upon results, as many patients are discharged before results return. The development of rapid turn-around-times (TATs) for genomic testing has begun to shift this paradigm. Rapid exome sequencing (rES) is increasingly being used as a diagnostic tool for critically ill infants with likely genetic disease and presents significant challenges to execute. We implemented a program, entitled the Rapid Inpatient Genomic Testing (RIGhT) project, to identify critically ill children for whom a molecular diagnosis is likely to change inpatient management. Two important goals of the RIGhT project were to provide appropriate genetic counseling, and to develop protocols to ensure efficient test coordination- both of which relied heavily on laboratory and clinic-based genetic counselors (GCs). Here, rES was performed on 27 inpatient trios from October 2016 to August 2018; laboratory and clinical GCs encountered significant challenges in the coordination of this testing. The GCs involved retrospectively reviewed these cases and identified three common challenges encountered during pretest counseling and coordination. The aim of this paper is to define these challenges using illustrative case examples that highlight the importance of including GCs to support rES programs.
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http://dx.doi.org/10.1002/jgc4.1116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6481675PMC
April 2019

Expanding clinical phenotype in CACNA1C related disorders: From neonatal onset severe epileptic encephalopathy to late-onset epilepsy.

Am J Med Genet A 2018 12 4;176(12):2733-2739. Epub 2018 Dec 4.

Division of Pediatric Neurology, Department of Neurology, University of Washington, Seattle, Washington.

CACNA1C (NM_000719.6) encodes an L-type calcium voltage-gated calcium channel (Ca 1.2), and pathogenic variants have been associated with two distinct clinical entities: Timothy syndrome and Brugada syndrome. Thus far, CACNA1C has not been reported as a gene associated with epileptic encephalopathy and is less commonly associated with epilepsy. We report three individuals from two families with variants in CACNA1C. Patient 1 presented with neonatal onset epileptic encephalopathy (NOEE) and was found to have a de novo missense variant in CACNA1C (c.4087G>A (p.V1363M)) on exome sequencing. In Family 2, Patient 2 presented with congenital cardiac anomalies and cardiomyopathy and was found to have a paternally inherited splice site variant, c.3717+1_3717+2insA, on a cardiomyopathy panel. Her father, Patient 3, presented with learning difficulties, late-onset epilepsy, and congenital cardiac anomalies. Family 2 highlights variable expressivity seen within a family. This case series expands the clinical and molecular phenotype of CACNA1C-related disorders and highlights the need to include CACNA1C on epilepsy gene panels.
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http://dx.doi.org/10.1002/ajmg.a.40657DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6312477PMC
December 2018

TANGO2: expanding the clinical phenotype and spectrum of pathogenic variants.

Genet Med 2019 03 24;21(3):601-607. Epub 2018 Sep 24.

GeneDx, Gaithersburg, Maryland, USA.

Purpose: TANGO2-related disorders were first described in 2016 and prior to this publication, only 15 individuals with TANGO2-related disorder were described in the literature. Primary features include metabolic crisis with rhabdomyolysis, encephalopathy, intellectual disability, seizures, and cardiac arrhythmias. We assess whether genotype and phenotype of TANGO2-related disorder has expanded since the initial discovery and determine the efficacy of exome sequencing (ES) as a diagnostic tool for detecting variants.

Methods: We present a series of 14 individuals from 11 unrelated families with complex medical and developmental histories, in whom ES or microarray identified compound heterozygous or homozygous variants in TANGO2.

Results: The initial presentation of patients with TANGO2-related disorders can be variable, including primarily neurological presentations. We expand the phenotype and genotype for TANGO2, highlighting the variability of the disorder.

Conclusion: TANGO2-related disorders can have a more diverse clinical presentation than previously anticipated. We illustrate the utility of routine ES data reanalysis whereby discovery of novel disease genes can lead to a diagnosis in previously unsolved cases and the need for additional copy-number variation analysis when ES is performed.
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http://dx.doi.org/10.1038/s41436-018-0137-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6752277PMC
March 2019

COQ2 nephropathy: a treatable cause of nephrotic syndrome in children.

Pediatr Nephrol 2018 07 10;33(7):1257-1261. Epub 2018 Apr 10.

Department of Pediatrics, Division of Genetic Medicine, Seattle Children's Hospital and University of Washington, Seattle, WA, USA.

Background: Nephrotic syndrome can be caused by a subgroup of mitochondrial diseases classified as primary coenzyme Q (CoQ) deficiency. Pathogenic COQ2 variants are a cause of primary CoQ deficiency and present with phenotypes ranging from isolated nephrotic syndrome to fatal multisystem disease.

Case-diagnosis/treatment: We report three pediatric patients with COQ2 variants presenting with nephrotic syndrome. Two of these patients had normal leukocyte CoQ levels prior to treatment. Pathologic findings varied from mesangial sclerosis to focal segmental glomerulosclerosis, with all patients having abnormal appearing mitochondria on kidney biopsy. In two of the three patients treated with CoQ supplementation, the nephrotic syndrome resolved; and at follow-up, both have normal renal function and stable proteinuria.

Conclusions: COQ2 nephropathy should be suspected in patients presenting with nephrotic syndrome, although less common than disease due to mutations in NPHS1, NPHS2, and WT1. The index of suspicion should remain high, and we suggest that providers consider genetic evaluation even in patients with normal leukocyte CoQ levels, as levels may be within normal range even with significant clinical disease. Early molecular diagnosis and specific treatment are essential in the management of this severe yet treatable condition.
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http://dx.doi.org/10.1007/s00467-018-3937-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5990461PMC
July 2018

De Novo Mutations in Protein Kinase Genes CAMK2A and CAMK2B Cause Intellectual Disability.

Am J Hum Genet 2017 Nov;101(5):768-788

Nottingham Regional Genetics Service, City Hospital Campus, Nottingham University Hospitals NHS Trust, The Gables, Hucknall Road, Nottingham NG5 1PB, UK.

Calcium/calmodulin-dependent protein kinase II (CAMK2) is one of the first proteins shown to be essential for normal learning and synaptic plasticity in mice, but its requirement for human brain development has not yet been established. Through a multi-center collaborative study based on a whole-exome sequencing approach, we identified 19 exceedingly rare de novo CAMK2A or CAMK2B variants in 24 unrelated individuals with intellectual disability. Variants were assessed for their effect on CAMK2 function and on neuronal migration. For both CAMK2A and CAMK2B, we identified mutations that decreased or increased CAMK2 auto-phosphorylation at Thr286/Thr287. We further found that all mutations affecting auto-phosphorylation also affected neuronal migration, highlighting the importance of tightly regulated CAMK2 auto-phosphorylation in neuronal function and neurodevelopment. Our data establish the importance of CAMK2A and CAMK2B and their auto-phosphorylation in human brain function and expand the phenotypic spectrum of the disorders caused by variants in key players of the glutamatergic signaling pathway.
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http://dx.doi.org/10.1016/j.ajhg.2017.10.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5673671PMC
November 2017
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