Publications by authors named "Laurie Demmer"

34 Publications

Defining the genotypic and phenotypic spectrum of X-linked MSL3-related disorder.

Genet Med 2021 Feb 11;23(2):384-395. Epub 2020 Nov 11.

Institute of Human Genetics, Technical University Munich, Munich, Germany.

Purpose: We sought to delineate the genotypic and phenotypic spectrum of female and male individuals with X-linked, MSL3-related disorder (Basilicata-Akhtar syndrome).

Methods: Twenty-five individuals (15 males, 10 females) with causative variants in MSL3 were ascertained through exome or genome sequencing at ten different sequencing centers.

Results: We identified multiple variant types in MSL3 (ten nonsense, six frameshift, four splice site, three missense, one in-frame-deletion, one multi-exon deletion), most proven to be de novo, and clustering in the terminal eight exons suggesting that truncating variants in the first five exons might be compensated by an alternative MSL3 transcript. Three-dimensional modeling of missense and splice variants indicated that these have a deleterious effect. The main clinical findings comprised developmental delay and intellectual disability ranging from mild to severe. Autism spectrum disorder, muscle tone abnormalities, and macrocephaly were common as well as hearing impairment and gastrointestinal problems. Hypoplasia of the cerebellar vermis emerged as a consistent magnetic resonance image (MRI) finding. Females and males were equally affected. Using facial analysis technology, a recognizable facial gestalt was determined.

Conclusion: Our aggregated data illustrate the genotypic and phenotypic spectrum of X-linked, MSL3-related disorder (Basilicata-Akhtar syndrome). Our cohort improves the understanding of disease related morbidity and allows us to propose detailed surveillance guidelines for affected individuals.
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http://dx.doi.org/10.1038/s41436-020-00993-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7862064PMC
February 2021

Systematic evidence-based review: outcomes from exome and genome sequencing for pediatric patients with congenital anomalies or intellectual disability.

Genet Med 2020 Jun 23;22(6):986-1004. Epub 2020 Mar 23.

Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.

Purpose: Exome and genome sequencing (ES/GS) are performed frequently in patients with congenital anomalies, developmental delay, or intellectual disability (CA/DD/ID), but the impact of results from ES/GS on clinical management and patient outcomes is not well characterized. A systematic evidence review (SER) can support future evidence-based guideline development for use of ES/GS in this patient population.

Methods: We undertook an SER to identify primary literature from January 2007 to March 2019 describing health, clinical, reproductive, and psychosocial outcomes resulting from ES/GS in patients with CA/DD/ID. A narrative synthesis of results was performed.

Results: We retrieved 2654 publications for full-text review from 7178 articles. Only 167 articles met our inclusion criteria, and these were primarily case reports or small case series of fewer than 20 patients. The most frequently reported outcomes from ES/GS were changes to clinical management or reproductive decision-making. Two studies reported on the reduction of mortality or morbidity or impact on quality of life following ES/GS.

Conclusion: There is evidence that ES/GS for patients with CA/DD/ID informs clinical and reproductive decision-making, which could lead to improved outcomes for patients and their family members. Further research is needed to generate evidence regarding health outcomes to inform robust guidelines regarding ES/GS in the care of patients with CA/DD/ID.
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http://dx.doi.org/10.1038/s41436-020-0771-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7222126PMC
June 2020

Bi-allelic Variants in RALGAPA1 Cause Profound Neurodevelopmental Disability, Muscular Hypotonia, Infantile Spasms, and Feeding Abnormalities.

Am J Hum Genet 2020 02 30;106(2):246-255. Epub 2020 Jan 30.

Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany. Electronic address:

Ral (Ras-like) GTPases play an important role in the control of cell migration and have been implicated in Ras-mediated tumorigenicity. Recently, variants in RALA were also described as a cause of intellectual disability and developmental delay, indicating the relevance of this pathway to neuropediatric diseases. Here, we report the identification of bi-allelic variants in RALGAPA1 (encoding Ral GTPase activating protein catalytic alpha subunit 1) in four unrelated individuals with profound neurodevelopmental disability, muscular hypotonia, feeding abnormalities, recurrent fever episodes, and infantile spasms . Dysplasia of corpus callosum with focal thinning of the posterior part and characteristic facial features appeared to be unifying findings. RalGAPA1 was absent in the fibroblasts derived from two affected individuals suggesting a loss-of-function effect of the RALGAPA1 variants. Consequently, RalA activity was increased in these cell lines, which is in keeping with the idea that RalGAPA1 deficiency causes a constitutive activation of RalA. Additionally, levels of RalGAPB, a scaffolding subunit of the RalGAP complex, were dramatically reduced, indicating a dysfunctional RalGAP complex. Moreover, RalGAPA1 deficiency clearly increased cell-surface levels of lipid raft components in detached fibroblasts, which might indicate that anchorage-dependence of cell growth signaling is disturbed. Our findings indicate that the dysregulation of the RalA pathway has an important impact on neuronal function and brain development. In light of the partially overlapping phenotype between RALA- and RALGAPA1-associated diseases, it appears likely that dysregulation of the RalA signaling pathway leads to a distinct group of genetic syndromes that we suggest could be named RALopathies.
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http://dx.doi.org/10.1016/j.ajhg.2020.01.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7010976PMC
February 2020

Spectrum of K 2.1 Dysfunction in KCNB1-Associated Neurodevelopmental Disorders.

Ann Neurol 2019 12 24;86(6):899-912. Epub 2019 Oct 24.

Departments of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL.

Objective: Pathogenic variants in KCNB1, encoding the voltage-gated potassium channel K 2.1, are associated with developmental and epileptic encephalopathy (DEE). Previous functional studies on a limited number of KCNB1 variants indicated a range of molecular mechanisms by which variants affect channel function, including loss of voltage sensitivity, loss of ion selectivity, and reduced cell-surface expression.

Methods: We evaluated a series of 17 KCNB1 variants associated with DEE or other neurodevelopmental disorders (NDDs) to rapidly ascertain channel dysfunction using high-throughput functional assays. Specifically, we investigated the biophysical properties and cell-surface expression of variant K 2.1 channels expressed in heterologous cells using high-throughput automated electrophysiology and immunocytochemistry-flow cytometry.

Results: Pathogenic variants exhibited diverse functional defects, including altered current density and shifts in the voltage dependence of activation and/or inactivation, as homotetramers or when coexpressed with wild-type K 2.1. Quantification of protein expression also identified variants with reduced total K 2.1 expression or deficient cell-surface expression.

Interpretation: Our study establishes a platform for rapid screening of K 2.1 functional defects caused by KCNB1 variants associated with DEE and other NDDs. This will aid in establishing KCNB1 variant pathogenicity and the mechanism of dysfunction, which will enable targeted strategies for therapeutic intervention based on molecular phenotype. ANN NEUROL 2019;86:899-912.
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http://dx.doi.org/10.1002/ana.25607DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7025436PMC
December 2019

An unusual case of nephrotic syndrome in a microcephalic infant: Answers.

Pediatr Nephrol 2019 11 8;34(11):2327-2329. Epub 2019 May 8.

Atrium Health's Levine Children's Hospital, 1000 Blythe Blvd, Charlotte, NC, 28203, USA.

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http://dx.doi.org/10.1007/s00467-019-04261-3DOI Listing
November 2019

An unusual case of nephrotic syndrome in a microcephalic infant: Questions.

Pediatr Nephrol 2019 11 8;34(11):2325-2326. Epub 2019 May 8.

Atrium Health's Levine Children's Hospital, 1000 Blythe Blvd, Charlotte, NC, 28203, USA.

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http://dx.doi.org/10.1007/s00467-019-04260-4DOI Listing
November 2019

Gene domain-specific DNA methylation episignatures highlight distinct molecular entities of ADNP syndrome.

Clin Epigenetics 2019 04 27;11(1):64. Epub 2019 Apr 27.

Department of Pathology and Laboratory Medicine, Western University, 800 Commissioner's Road E, London, ON, N6A 5W9, Canada.

Background: ADNP syndrome is a rare Mendelian disorder characterized by global developmental delay, intellectual disability, and autism. It is caused by truncating mutations in ADNP, which is involved in chromatin regulation. We hypothesized that the disruption of chromatin regulation might result in specific DNA methylation patterns that could be used in the molecular diagnosis of ADNP syndrome.

Results: We identified two distinct and partially opposing genomic DNA methylation episignatures in the peripheral blood samples from 22 patients with ADNP syndrome. The "epi-ADNP-1" episignature included ~ 6000 mostly hypomethylated CpGs, and the "epi-ADNP-2" episignature included ~ 1000 predominantly hypermethylated CpGs. The two signatures correlated with the locations of the ADNP mutations. Epi-ADNP-1 mutations occupy the N- and C-terminus, and epi-ADNP-2 mutations are centered on the nuclear localization signal. The episignatures were enriched for genes involved in neuronal system development and function. A classifier trained on these profiles yielded full sensitivity and specificity in detecting patients with either of the two episignatures. Applying this model to seven patients with uncertain clinical diagnosis enabled reclassification of genetic variants of uncertain significance and assigned new diagnosis when the primary clinical suspicion was not correct. When applied to a large cohort of unresolved patients with developmental delay (N = 1150), the model predicted three additional previously undiagnosed patients to have ADNP syndrome. DNA sequencing of these subjects, wherever available, identified pathogenic mutations within the gene domains predicted by the model.

Conclusions: We describe the first Mendelian condition with two distinct episignatures caused by mutations in a single gene. These highly sensitive and specific DNA methylation episignatures enable diagnosis, screening, and genetic variant classifications in ADNP syndrome.
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http://dx.doi.org/10.1186/s13148-019-0658-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6487024PMC
April 2019

Cornelia de Lange syndrome in diverse populations.

Am J Med Genet A 2019 02 6;179(2):150-158. Epub 2019 Jan 6.

Division of Human Genetics and Molecular Biology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.

Cornelia de Lange syndrome (CdLS) is a dominant multisystemic malformation syndrome due to mutations in five genes-NIPBL, SMC1A, HDAC8, SMC3, and RAD21. The characteristic facial dysmorphisms include microcephaly, arched eyebrows, synophrys, short nose with depressed bridge and anteverted nares, long philtrum, thin lips, micrognathia, and hypertrichosis. Most affected individuals have intellectual disability, growth deficiency, and upper limb anomalies. This study looked at individuals from diverse populations with both clinical and molecularly confirmed diagnoses of CdLS by facial analysis technology. Clinical data and images from 246 individuals with CdLS were obtained from 15 countries. This cohort included 49% female patients and ages ranged from infancy to 37 years. Individuals were grouped into ancestry categories of African descent, Asian, Latin American, Middle Eastern, and Caucasian. Across these populations, 14 features showed a statistically significant difference. The most common facial features found in all ancestry groups included synophrys, short nose with anteverted nares, and a long philtrum with thin vermillion of the upper lip. Using facial analysis technology we compared 246 individuals with CdLS to 246 gender/age matched controls and found that sensitivity was equal or greater than 95% for all groups. Specificity was equal or greater than 91%. In conclusion, we present consistent clinical findings from global populations with CdLS while demonstrating how facial analysis technology can be a tool to support accurate diagnoses in the clinical setting. This work, along with prior studies in this arena, will assist in earlier detection, recognition, and treatment of CdLS worldwide.
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http://dx.doi.org/10.1002/ajmg.a.61033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6367950PMC
February 2019

De Novo Variants in MAPK8IP3 Cause Intellectual Disability with Variable Brain Anomalies.

Am J Hum Genet 2019 02 3;104(2):203-212. Epub 2019 Jan 3.

Institute of Human Genetics, University of Leipzig Hospitals and Clinics, Leipzig 04103, Germany.

Using exome sequencing, we have identified de novo variants in MAPK8IP3 in 13 unrelated individuals presenting with an overlapping phenotype of mild to severe intellectual disability. The de novo variants comprise six missense variants, three of which are recurrent, and three truncating variants. Brain anomalies such as perisylvian polymicrogyria, cerebral or cerebellar atrophy, and hypoplasia of the corpus callosum were consistent among individuals harboring recurrent de novo missense variants. MAPK8IP3 has been shown to be involved in the retrograde axonal-transport machinery, but many of its specific functions are yet to be elucidated. Using the CRISPR-Cas9 system to target six conserved amino acid positions in Caenorhabditis elegans, we found that two of the six investigated human alterations led to a significantly elevated density of axonal lysosomes, and five variants were associated with adverse locomotion. Reverse-engineering normalized the observed adverse effects back to wild-type levels. Combining genetic, phenotypic, and functional findings, as well as the significant enrichment of de novo variants in MAPK8IP3 within our total cohort of 27,232 individuals who underwent exome sequencing, we implicate de novo variants in MAPK8IP3 as a cause of a neurodevelopmental disorder with intellectual disability and variable brain anomalies.
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http://dx.doi.org/10.1016/j.ajhg.2018.12.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6369540PMC
February 2019

Development, Implementation, and Assessment of a Genetics Curriculum Across Institutions.

AJP Rep 2016 Oct;6(4):e372-e377

Division of Maternal-Fetal Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.

 Many residency programs offer limited exposure and minimal didactic time genetics, despite its frequent use in obstetrics and gynecology. The objective of this study was to develop, pilot, and assess a three-module women's health genetics curriculum for residents that was easily transferable between institutions.  An interactive three-module genetics curriculum covering basic principles, prenatal screening/diagnosis, and cancer genetics was developed. A pre- and posttests were used to assess improvement in knowledge. Subjective feedback was obtained to assess curricular satisfaction. The data were analyzed with descriptive statistics.  The curriculum was administered at two institutions. Forty-eight residents attended ≥ 1 session. Twenty completed the pretest, and 23 completed the posttest. At the first institution, using audience response system, the percentage correct per question increased on 10/14 questions between pre- and posttests. All students felt the curriculum was useful and would strongly recommend to other residents. At the second institution, pre/posttests were distributed on paper. Mean scores significantly improved between pre- and posttests ( = 0.007). On the pretest, no residents scored > 70%. However, 8/13 scored > 70% on the posttest ( = 0.002). Instructors at both institutions described the curriculum as easy to use/implement.  This three-module workshop on women's health genetics was easily implemented across institutions and led to increased knowledge.
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http://dx.doi.org/10.1055/s-0036-1593831DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5097042PMC
October 2016

Recommendations for the integration of genomics into clinical practice.

Genet Med 2016 11 12;18(11):1075-1084. Epub 2016 May 12.

Individualized Medical Genetics Center, Division of Human Genetics, Department of Pediatrics, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.

The introduction of diagnostic clinical genome and exome sequencing (CGES) is changing the scope of practice for clinical geneticists. Many large institutions are making a significant investment in infrastructure and technology, allowing clinicians to access CGES, especially as health-care coverage begins to extend to clinically indicated genomic sequencing-based tests. Translating and realizing the comprehensive clinical benefits of genomic medicine remain a key challenge for the current and future care of patients. With the increasing application of CGES, it is necessary for geneticists and other health-care providers to understand its benefits and limitations in order to interpret the clinical relevance of genomic variants identified in the context of health and disease. New, collaborative working relationships with specialists across diverse disciplines (e.g., clinicians, laboratorians, bioinformaticians) will undoubtedly be key attributes of the future practice of clinical genetics and may serve as an example for other specialties in medicine. These new skills and relationships will also inform the development of the future model of clinical genetics training curricula. To address the evolving role of the clinical geneticist in the rapidly changing climate of genomic medicine, two Clinical Genetics Think Tank meetings were held that brought together physicians, laboratorians, scientists, genetic counselors, trainees, and patients with experience in clinical genetics, genetic diagnostics, and genetics education. This article provides recommendations that will guide the integration of genomics into clinical practice.Genet Med 18 11, 1075-1084.
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http://dx.doi.org/10.1038/gim.2016.17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5557020PMC
November 2016

Autosomal recessive MFN2-related Charcot-Marie-Tooth disease with diaphragmatic weakness: Case report and literature review.

Am J Med Genet A 2016 06 8;170(6):1580-4. Epub 2016 Mar 8.

Department of Pediatrics, Levine Children's Hospital/Carolinas Healthcare System, Charlotte, North Carolina.

Pathogenic variants in the mitofusin 2 gene (MFN2) are the most common cause of autosomal dominant Charcot-Marie-Tooth (CMT2) disease, which is typically characterized by axonal sensorimotor neuropathy. We report on a 7-month-old white female with hypotonia, motor delay, distal weakness, and motor/sensory axonal neuropathy in which next-generation sequencing analysis identified compound heterozygous pathogenic variants (c.2054_2069_1170del and c.392A>G) in MFN2. A review of the literature reveals that sporadic and familial cases of compound heterozygous or homozygous pathogenic MFN2 variants have been infrequently described, which indicates that MFN2 can also be inherited in a recessive manner. This case highlights several clinical findings not typically associated with MFN2 pathogenic variants, including young age of onset and rapidly progressing diaphragmatic paresis that necessitated tracheostomy and mechanical ventilation, and adds to the growing list of features identified in autosomal recessive MFN2-related CMT2. Our patient with MFN2-related CMT2 expands the clinical and mutational spectrum of individuals with autosomal recessive CMT2 and identifies a new clinical feature that warrants further observation. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/ajmg.a.37611DOI Listing
June 2016

ALG1-CDG: Clinical and Molecular Characterization of 39 Unreported Patients.

Hum Mutat 2016 07 21;37(7):653-60. Epub 2016 Mar 21.

Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California.

Congenital disorders of glycosylation (CDG) arise from pathogenic mutations in over 100 genes leading to impaired protein or lipid glycosylation. ALG1 encodes a β1,4 mannosyltransferase that catalyzes the addition of the first of nine mannose moieties to form a dolichol-lipid linked oligosaccharide intermediate required for proper N-linked glycosylation. ALG1 mutations cause a rare autosomal recessive disorder termed ALG1-CDG. To date 13 mutations in 18 patients from 14 families have been described with varying degrees of clinical severity. We identified and characterized 39 previously unreported cases of ALG1-CDG from 32 families and add 26 new mutations. Pathogenicity of each mutation was confirmed based on its inability to rescue impaired growth or hypoglycosylation of a standard biomarker in an alg1-deficient yeast strain. Using this approach we could not establish a rank order comparison of biomarker glycosylation and patient phenotype, but we identified mutations with a lethal outcome in the first two years of life. The recently identified protein-linked xeno-tetrasaccharide biomarker, NeuAc-Gal-GlcNAc2 , was seen in all 27 patients tested. Our study triples the number of known patients and expands the molecular and clinical correlates of this disorder.
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http://dx.doi.org/10.1002/humu.22983DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4907823PMC
July 2016

Surveying the current landscape of clinical genetics residency training.

Genet Med 2015 May 18;17(5):386-90. Epub 2014 Sep 18.

Children's Hospital, Greenville Health System, Greenville, South Carolina, USA.

Purpose: Further knowledge about medical genetics residency training structure and function could help advance this educational process.

Methods: Medical genetics residency program directors were surveyed about their trainees' backgrounds and skills as well as the recruitment and matching process.

Results: Previous resident training was predominantly in pediatrics (49%). Average ratings of residents' beginning clinical knowledge (scale of 1-10, minimal to superior) were: dysmorphology - 3.5, inborn errors of metabolism - 2.5, prenatal genetics - 2.6, and cancer genetics - 2.8. On average, four months of research were required for categorical residency and fifteen months for combined residency. For the 2011 transition to ERAS/NRMP, 69% of program directors were extremely or somewhat prepared; however, 21% felt unprepared. The number of trainees at most institutions remained unchanged. 36% of respondents reported that ERAS/NRMP has had no impact on recruitment of trainees, and 26% felt it has had a slightly positive impact. Continued utilization was recommended by 71% while 5% disagreed.

Conclusion: Genetics residents come from diverse training backgrounds. Their education can be directed toward specific areas of perceived initial weakness. ERAS/NRMP has not drastically increased entrance into the field. Further discussions are merited regarding enhancement of medical genetics residency recruitment and training.
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http://dx.doi.org/10.1038/gim.2014.108DOI Listing
May 2015

Professional medical education and genomics.

Annu Rev Genomics Hum Genet 2014 12;15:507-16. Epub 2014 Mar 12.

Department of Pediatrics, Carolinas Medical Center, Charlotte, North Carolina 28232; email:

Genomic medicine is a relatively new concept that involves using individual patients' genomic results in their clinical care. Genetic technology has advanced swiftly over the past decade, and most providers have been left behind without an understanding of this complex field. To realize its full potential, genomic medicine must be both understood and accepted by the greater medical community. The current state of professional medical education in genomics and genomic medicine is reviewed, including ongoing plans to expand educational efforts for medical students, clinical geneticists, and nongeneticist physicians.
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http://dx.doi.org/10.1146/annurev-genom-090413-025522DOI Listing
May 2015

A description of spina bifida cases and co-occurring malformations, 1976-2011.

Am J Med Genet A 2014 Feb 19;164A(2):432-40. Epub 2013 Dec 19.

Slone Epidemiology Center at Boston University, Boston, Massachusetts.

Mandatory folic acid fortification in the United States corresponded with a decline in the prevalence of spina bifida (SB). The aim of this study was to describe the epidemiologic characteristics of isolated versus non-isolated SB cases in both pre- and post-fortification periods. SB cases in the Slone Epidemiology Center Birth Defects Study from 1976 to 2011 without chromosomal anomalies and syndromes were included. A maternal interview, conducted within 6 months of delivery, collected information on demographics, reproductive history, diet, and supplement use. Daily folic acid intake in the periconceptional period was calculated using both dietary and supplement information and categorized as low intake (<400 µg/day) or high intake (≥400 µg/day). SB cases (n = 1170) were classified as isolated (80.4%) or non-isolated (19.1%). Non-isolated cases were further divided into subgroups based on accompanying major malformations (midline, renal, genital, heart, laterality). Compared to non-isolated cases, isolated cases were more likely to be white, non-Hispanic and have more than 12 years of education. Cases in the renal, genital, and heart subgroups had the lowest proportions of mothers with a high folic acid intake. The change from pre- to post-fortification was associated with a decrease in the proportion of isolated cases from 83% to 72%, though in both periods isolated cases were more likely to be female and their mothers were more likely to have high folic acid intake. These findings highlight the importance of separating isolated and non-isolated cases in etiologic research of SB.
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http://dx.doi.org/10.1002/ajmg.a.36324DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4353584PMC
February 2014

Mouse model implicates GNB3 duplication in a childhood obesity syndrome.

Proc Natl Acad Sci U S A 2013 Sep 26;110(37):14990-4. Epub 2013 Aug 26.

Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322.

Obesity is a highly heritable condition and a risk factor for other diseases, including type 2 diabetes, cardiovascular disease, hypertension, and cancer. Recently, genomic copy number variation (CNV) has been implicated in cases of early onset obesity that may be comorbid with intellectual disability. Here, we describe a recurrent CNV that causes a syndrome associated with intellectual disability, seizures, macrocephaly, and obesity. This unbalanced chromosome translocation leads to duplication of over 100 genes on chromosome 12, including the obesity candidate gene G protein β3 (GNB3). We generated a transgenic mouse model that carries an extra copy of GNB3, weighs significantly more than its wild-type littermates, and has excess intraabdominal fat accumulation. GNB3 is highly expressed in the brain, consistent with G-protein signaling involved in satiety and/or metabolism. These functional data connect GNB3 duplication and overexpression to elevated body mass index and provide evidence for a genetic syndrome caused by a recurrent CNV.
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http://dx.doi.org/10.1073/pnas.1305999110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3773733PMC
September 2013

Expanding the SHOC2 mutation associated phenotype of Noonan syndrome with loose anagen hair: structural brain anomalies and myelofibrosis.

Am J Med Genet A 2013 Oct 5;161A(10):2420-30. Epub 2013 Aug 5.

Division of Medical Genetics, A. I. duPont Hospital for Children, Wilmington, Delaware.

Noonan syndrome is a heterogenous rasopathy typically presenting with short stature, characteristic facial features, cardiac abnormalities including pulmonic valve stenosis, ASD and hypertrophic cardiomyopathy (HCM), cryptorchidism, ectodermal abnormalities, and learning differences. The phenotype is variable, and limited genotype phenotype correlation exists with SOS1 mutations often associated with normal cognition and stature, RAF1 mutations entailing a high HCM risk, and certain PTPN11 mutations predisposing to juvenile myelomonocytic leukemia. The recently identified SHOC2 mutation (p.Ser2Gly) causes Noonan syndrome with loose anagen hair. We report five patients with this mutation. All had skin hyperpigmentation, sparse light colored hair, increased fine wrinkles, ligamentous laxity, developmental delay, and 4/4 had a structural cardiac anomaly. Hypotonia and macrocephaly occurred in 4/5 (80%); 3/5 (60%) had polyhydramnios, increased birth weight or required use of a feeding tube. Distinctive brain abnormalities included relative megalencephaly and enlarged subarachnoid spaces suggestive of benign external hydrocephalus, and a relatively small posterior fossa as indicated by a vertical tentorium. The combination of a large brain with a small posterior fossa likely resulted in the high rate of cerebellar tonsillar ectopia (3/4; 75%). Periventricular nodular heterotopia was seen in one patient with a thick and dysplastic corpus callosum. We report on the first hematologic neoplasm, myelofibrosis, in a 2-year-old patient with SHOC2 mutation. Myelofibrosis is exceedingly rare in children and young adults. The absence of a somatic JAK2 mutation, seen in the majority of patients with myelofibrosis, is noteworthy as it suggests that germline or somatic SHOC2 mutations are causally involved in myelofibrosis.
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http://dx.doi.org/10.1002/ajmg.a.36098DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3787995PMC
October 2013

Keratoconus in Costello syndrome.

Am J Med Genet A 2013 May 13;161A(5):1132-6. Epub 2013 Mar 13.

Division of Medical Genetics, A. I. duPont Hospital for Children, Wilmington, DE, USA.

Keratoconus is a corneal dystrophy with progressive corneal thinning resulting in abnormal corneal shape and astigmatism. Corneal hydrops and rupture can occur and corneal transplant may become necessary. While keratoconus is rare in the general population occurring in about 1/2,000 individuals, it is more common in individuals with intellectual disability and syndromic conditions. Connective tissue abnormalities, most typically brittle cornea syndrome, have frequently been reported in association with keratoconus. Here, we report on bilateral keratoconus with acute hydrops in the left eye of a 24-year-old male with Costello syndrome. The patient was treated medically. After resolution of the hydrops, he had significant visual impairment from the resulting irregular astigmatism and scarring. This is the second report of keratoconus in Costello syndrome, suggesting an increased risk for this corneal dystrophy in individuals with Costello syndrome. Ongoing ophthalmological surveillance may be necessary for adult individuals with Costello syndrome, and apparent vision changes should be evaluated expediently.
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http://dx.doi.org/10.1002/ajmg.a.35816DOI Listing
May 2013

Maternal tea consumption during early pregnancy and the risk of spina bifida.

Birth Defects Res A Clin Mol Teratol 2012 Oct 29;94(10):756-61. Epub 2012 May 29.

Slone Epidemiology Center at Boston University, Boston, MA, USA.

Studies have demonstrated that catechin, an antioxidant found in tea, can reduce the bioavailability of folate. Because periconceptional folic acid intake has been demonstrated to reduce the risk of spina bifida, tea consumption may put pregnant women at risk because of its possible antifolate properties. Using data collected in the Slone Epidemiology Center Birth Defects Study, we examined whether tea consumption during early pregnancy was associated with an increased risk of spina bifida. Mothers of 518 spina bifida cases and 6424 controls were interviewed within 6 months after delivery about pregnancy events and exposures. Data on tea intake were collected during three periods (1976-1988, 1998-2005 and 2009-2010). Logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for study center. Intake of both periconceptional food folate and diet and supplemental folic acid were examined as a potential effect modifier. For 1976 to 1988, ORs were not elevated for daily tea intake. For 1998 and onward, ORs were also close to 1.0, but there was a modest increase for those who drank more than 3 cups/day (OR, 1.92; 95% CI, 0.84-4.38). Among women with total folic acid intake greater than 400 μg, consumption of 3 cups or more of tea per day was associated with an increased risk of spina bifida in 1976 to 1988 (OR, 2.04; 95% CI, 0.69-7.66) and in the later periods (OR, 3.13; 95% CI, 0.87-11.33). Our data do not support an overall association between tea consumption and spina bifida, but there is a suggestion of a possible interaction between higher levels of folic acid intake and tea consumption.
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http://dx.doi.org/10.1002/bdra.23025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4557736PMC
October 2012

Noonan syndrome due to a SHOC2 mutation presenting with fetal distress and fatal hypertrophic cardiomyopathy in a premature infant.

Am J Med Genet A 2012 Jun 23;158A(6):1411-3. Epub 2012 Apr 23.

Division of Newborn Medicine, Floating Hospital for Children at Tufts Medical Center, Boston, Massachusetts 02111, USA.

We report on a patient with Noonan syndrome due to SHOC2 missense mutation predicting p.Ser2Gly, recently described in association with Noonan syndrome. The male infant presented with fetal distress requiring premature delivery at 32 weeks and was noted to have dysmorphic features, edema, hepatosplenomegaly, leukocytosis, thrombocytopenia, and respiratory distress following birth. An echocardiogram revealed hypertrophic cardiomyopathy with left ventricular outflow tract obstruction. The infant's cardiac lesion rapidly progressed, and he was discharged home for palliative care. Clinical testing of genes causative of Noonan syndrome and related disorders detected the previously reported, pathogenic, de novo SHOC2 missense mutation predicting p.Ser2Gly. The patient's cardiac findings and features were not typical for those individuals previously reported with this SHOC2 mutation and thus expand the clinical phenotype.
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http://dx.doi.org/10.1002/ajmg.a.35318DOI Listing
June 2012

Mutation spectrum in the large GTPase dynamin 2, and genotype-phenotype correlation in autosomal dominant centronuclear myopathy.

Hum Mutat 2012 Jun 4;33(6):949-59. Epub 2012 Apr 4.

Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U964/CNRS UMR7104, University of Strasbourg, Collège de France, Illkirch, France.

Centronuclear myopathy (CNM) is a genetically heterogeneous disorder associated with general skeletal muscle weakness, type I fiber predominance and atrophy, and abnormally centralized nuclei. Autosomal dominant CNM is due to mutations in the large GTPase dynamin 2 (DNM2), a mechanochemical enzyme regulating cytoskeleton and membrane trafficking in cells. To date, 40 families with CNM-related DNM2 mutations have been described, and here we report 60 additional families encompassing a broad genotypic and phenotypic spectrum. In total, 18 different mutations are reported in 100 families and our cohort harbors nine known and four new mutations, including the first splice-site mutation. Genotype-phenotype correlation hypotheses are drawn from the published and new data, and allow an efficient screening strategy for molecular diagnosis. In addition to CNM, dissimilar DNM2 mutations are associated with Charcot-Marie-Tooth (CMT) peripheral neuropathy (CMTD1B and CMT2M), suggesting a tissue-specific impact of the mutations. In this study, we discuss the possible clinical overlap of CNM and CMT, and the biological significance of the respective mutations based on the known functions of dynamin 2 and its protein structure. Defects in membrane trafficking due to DNM2 mutations potentially represent a common pathological mechanism in CNM and CMT.
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http://dx.doi.org/10.1002/humu.22067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3374402PMC
June 2012

The development and implementation of an in-service exam for medical genetics residency programs.

Genet Med 2012 May 26;14(5):552-7. Epub 2012 Jan 26.

Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA.

Purpose: In-service exams are a commonly used educational tool in postgraduate medical education. Although most specialties utilize such an exam, medical genetics did not. It was decided in the spring of 2009 at the inaugural Medical Genetics Residency Program Directors (PDs) Group meeting to develop and implement such a test.

Methods: Using questions sent in from PDs, a 125-question exam was created, with 125 multiple-choice questions according to the format of the National Board of Medical Examiners. The exam covered genetics in the following areas: basic/molecular (~45 questions), cancer and adult (20), prenatal (20), biochemical (20), pediatric/dysmorphology (20). The exam was administered for the first time in February 2010, and again with modifications in 2011.

Results: In total, 174 trainees from 35 programs completed the exam in 2010; in 2011 the number increased to 214, representing 39 US programs, and 4 Canadian programs. For both years, most participants were medical genetics residents (106 in 2010; 127 in 2011), but a substantial number of clinical laboratory fellows also participated (68 in 2010; 85 in 2011).

Conclusion: The development and implementation of this test were an overall success, in that in two years we were able to secure almost 100% participation from medical genetics residency programs, and that we created an infrastructure to develop and implement this exam on a yearly basis. There is need for improvement, notably in the relatively low mean score and relatively narrow spread of scores. However, we believe that, with efforts under way to improve the quality of the questions, the in-service exam will become a fundamental tool in medical genetics residency education.
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http://dx.doi.org/10.1038/gim.2011.41DOI Listing
May 2012

Lessons learned from the introduction of personalized genotyping into a medical school curriculum.

Genet Med 2011 Jan;13(1):63-6

Department of Chemistry, Tufts University, Medford, Massachusetts, USA.

Purpose: There is an expanding gap between the availability of direct-to-consumer whole genome testing and physician knowledge regarding interpretation of test results. Advances in the genomic literacy of health care providers will be necessary for genomics to exert its potential to affect clinical practice. However, implementation of a major shift in medical education to include genomics is not easily done. The purpose of this educational report is to describe efforts to incorporate knowledge of personalized medicine into a medical school curriculum.

Methods: In this report, we describe the experiences, both good and bad, of a multidisciplinary faculty group that examined ways to improve genomic education at Tufts University School of Medicine during a 16-month period.

Results: The results of the faculty's deliberation process resulted in the use of anonymous, rather than student genomes, to teach material on genomic medicine.

Conclusion: Increased medical school education regarding genomic analysis and personalized medicine is a necessity, both to be able to translate the advances made by the Human Genome Project into improvements in human health and to begin to think of diseases as disruptions in specific pathways. Our experiences illustrate that adding this material to a medical school curriculum is a complex process that deserves careful thought and broad discussion within the academic community.
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http://dx.doi.org/10.1097/GIM.0b013e3181f872acDOI Listing
January 2011

Deletion 17q12 is a recurrent copy number variant that confers high risk of autism and schizophrenia.

Am J Hum Genet 2010 Nov 4;87(5):618-30. Epub 2010 Nov 4.

Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA.

Autism spectrum disorders (ASD) and schizophrenia are neurodevelopmental disorders for which recent evidence indicates an important etiologic role for rare copy number variants (CNVs) and suggests common genetic mechanisms. We performed cytogenomic array analysis in a discovery sample of patients with neurodevelopmental disorders referred for clinical testing. We detected a recurrent 1.4 Mb deletion at 17q12, which harbors HNF1B, the gene responsible for renal cysts and diabetes syndrome (RCAD), in 18/15,749 patients, including several with ASD, but 0/4,519 controls. We identified additional shared phenotypic features among nine patients available for clinical assessment, including macrocephaly, characteristic facial features, renal anomalies, and neurocognitive impairments. In a large follow-up sample, the same deletion was identified in 2/1,182 ASD/neurocognitive impairment and in 4/6,340 schizophrenia patients, but in 0/47,929 controls (corrected p = 7.37 × 10⁻⁵). These data demonstrate that deletion 17q12 is a recurrent, pathogenic CNV that confers a very high risk for ASD and schizophrenia and show that one or more of the 15 genes in the deleted interval is dosage sensitive and essential for normal brain development and function. In addition, the phenotypic features of patients with this CNV are consistent with a contiguous gene syndrome that extends beyond RCAD, which is caused by HNF1B mutations only.
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http://dx.doi.org/10.1016/j.ajhg.2010.10.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2978962PMC
November 2010

Genetics for the pediatric anesthesiologist: a primer on congenital malformations, pharmacogenetics, and proteomics.

Anesth Analg 2010 Nov 14;111(5):1264-74. Epub 2010 Sep 14.

Department of Anesthesiology and Pediatrics, The Children's Hospital, University of Colorado Denver, Aurora, CO 80045, USA.

Molecular genetics is the study, at the molecular level, of how genetic information is stored, inherited, and expressed and of how it influences the structure and function of cells in health and in disease. Although molecular approaches have been used for decades in the laboratory and are at the core of modern medical education, they are only now beginning to influence clinical practice. A variety of sophisticated techniques permit rapid and affordable DNA sequencing, gene expression profiling, gene cloning, gene manipulation, gene transfer, recombinant protein production, and other technologies of enormous biomedical importance. Success in genomics has spawned additional ambitious endeavors, including proteomics, pharmacogenomics, and bioinformatics. These techniques are providing new diagnostic, prognostic, and therapeutic opportunities in all areas of medicine, including anesthesiology. With the use of molecular criteria and the diminishing cost of analytic technologies, anesthetic practice will become more individualized, and greater emphasis will be placed on the patient's genetic makeup. Both surgical and nonsurgical decisions will increasingly accommodate molecular data crucial to perioperative anesthetic management. In this article we have summarized three lectures on congenital malformations, pharmacogenetics, and proteomics presented at the 22nd Annual Meeting of the Society for Pediatric Anesthesia.
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http://dx.doi.org/10.1213/ANE.0b013e3181f3fbd4DOI Listing
November 2010

Clinical genetic testing for patients with autism spectrum disorders.

Pediatrics 2010 Apr 15;125(4):e727-35. Epub 2010 Mar 15.

Autism Consortium, Boston, Massachusetts, USA.

Background: Multiple lines of evidence indicate a strong genetic contribution to autism spectrum disorders (ASDs). Current guidelines for clinical genetic testing recommend a G-banded karyotype to detect chromosomal abnormalities and fragile X DNA testing, but guidelines for chromosomal microarray analysis have not been established.

Patients And Methods: A cohort of 933 patients received clinical genetic testing for a diagnosis of ASD between January 2006 and December 2008. Clinical genetic testing included G-banded karyotype, fragile X testing, and chromosomal microarray (CMA) to test for submicroscopic genomic deletions and duplications. Diagnostic yield of clinically significant genetic changes was compared.

Results: Karyotype yielded abnormal results in 19 of 852 patients (2.23% [95% confidence interval (CI): 1.73%-2.73%]), fragile X testing was abnormal in 4 of 861 (0.46% [95% CI: 0.36%-0.56%]), and CMA identified deletions or duplications in 154 of 848 patients (18.2% [95% CI: 14.76%-21.64%]). CMA results for 59 of 848 patients (7.0% [95% CI: 5.5%-8.5%]) were considered abnormal, which includes variants associated with known genomic disorders or variants of possible significance. CMA results were normal in 10 of 852 patients (1.2%) with abnormal karyotype due to balanced rearrangements or unidentified marker chromosome. CMA with whole-genome coverage and CMA with targeted genomic regions detected clinically relevant copy-number changes in 7.3% (51 of 697) and 5.3% (8 of 151) of patients, respectively, both higher than karyotype. With the exception of recurrent deletion and duplication of chromosome 16p11.2 and 15q13.2q13.3, most copy-number changes were unique or identified in only a small subset of patients.

Conclusions: CMA had the highest detection rate among clinically available genetic tests for patients with ASD. Interpretation of microarray data is complicated by the presence of both novel and recurrent copy-number variants of unknown significance. Despite these limitations, CMA should be considered as part of the initial diagnostic evaluation of patients with ASD.
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http://dx.doi.org/10.1542/peds.2009-1684DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4247857PMC
April 2010

Prenatal features of Costello syndrome: ultrasonographic findings and atrial tachycardia.

Prenat Diagn 2009 Jul;29(7):682-90

Genetics Unit, Department of Pediatrics, MassGeneral Hospital for Children, 185 Cambridge Street, Simches 2222, Boston, MA, USA.

Objective: Delineate prenatal features of Costello syndrome (caused by HRAS mutations), which consists of mental retardation, facial, cardiovascular, skin, and musculoskeletal anomalies, and tumor predisposition.

Methods: Literature and new cases classified as Group I (pre-HRAS), Group II (HRAS confirmed), and Group III (HRAS confirmed in natural history study, plus three contributed cases).

Results: Polyhydramnios occurred in most (mean 79%) pregnancies of cases in Groups I (98), II (107), and III (17); advanced paternal age and prematurity were noted in approximately half. Less frequent were nuchal thickening, ascites, shortened long bones, abnormal hand posture, ventriculomegaly, macrosomia, and macrocephaly. Fetal arrhythmia occurred in nine cases (six supraventricular or unspecified tachycardia, one unspecified arrhythmia, and two premature atrial contractions, PACs); excluding three new cases and two with PACs, the estimated prenatal frequency is 4/222 (2%).

Conclusion: Costello syndrome can be suspected prenatally when polyhydramnios is accompanied by nuchal thickening, hydrops, shortened long bones, abnormal hand posture, ventriculomegaly, large size, and macrocephaly, and especially fetal atrial tachycardia. Consideration should be given for timely prenatal diagnostic studies for confirmative HRAS gene mutations and for maternal treatment of serious fetal arrhythmia.
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http://dx.doi.org/10.1002/pd.2276DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4293073PMC
July 2009

Male-to-male transmission of Costello syndrome: G12S HRAS germline mutation inherited from a father with somatic mosaicism.

Am J Med Genet A 2009 Mar;149A(3):315-21

Nemours Biomedical Research, Nemours Children's Clinic, Wilmington, Delaware 19803, USA.

Costello syndrome is a rare congenital anomaly syndrome associated with mental retardation and predisposition to benign and malignant tumors, caused by heterozygous missense mutations in the HRAS oncogene. Previously, all molecularly analyzed mutations appeared de novo, and most arose in the paternal germline. A single patient with somatic mosaicism for a Costello syndrome causing HRAS mutation has been reported. Here we describe the first documented transmission of an HRAS mutation from a parent with somatic mosaicism to a child with typical Costello syndrome. Prior to the identification of the underlying gene mutation in Costello syndrome, this family had been identified clinically. The proband was subsequently found to carry a G12S HRAS germline mutation. Testing of the parents for parental origin identified his father as mosaic for the same HRAS mutation. The mother was found not to carry an HRAS mutation. The causative familial mutation is identified as a c.34G > A, which is the most common mutation in the HRAS gene in patients with Costello syndrome. The father carries the mutation in 7-8% of his alleles. This is the second case of mosaicism observed in Costello syndrome and the first direct molecular evidence of father-to-son transmission of the disease-causing mutation. Our observation underlines the importance of parental evaluation, and may have implications for genetic counseling and clinical practice.
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http://dx.doi.org/10.1002/ajmg.a.32639DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2653086PMC
March 2009