William A Gahl

Johannes Gutenberg-Universität Mainz, Mayence, Rheinland-Pfalz, Germany

Are you William A Gahl?

Claim your profile

Publications (497)3442.38 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Background Whole-exome sequencing (WES) is rapidly evolving into a tool of choice for rapid, and inexpensive identification of molecular genetic lesions within targeted regions of the human genome. While biases in WES coverage of nucleotides in targeted regions are recognized, it is not well understood how repetition of WES improves the interpretation of sequencing results in a clinical diagnostic setting. Method To address this, we compared independently generated exome-capture of six individuals from three-generations sequenced in triplicate. This generated between 48x-86x mean target depth of high-quality mapped bases (>Q20) for each technical replicate library. Cumulatively, we achieved 179 - 208x average target coverage for each individual in the pedigree. Using this experimental design, we evaluated stochastics in WES interpretation, genotyping sensitivity, and accuracy to detect de novo variants. Results In this study, we show that repetition of WES improved the interpretation of the capture target regions after aggregating the data (93.5 - 93.9 %). Compared to 81.2 - 89.6 % (50.2-55.4 Mb of 61.7 M) coverage of targeted bases at ≥20x in the individual technical replicates, the aggregated data covered 93.5 - 93.9 % of targeted bases (57.7 – 58.0 of 61.7 M) at ≥20x threshold, suggesting a 4.3 – 12.7 % improvement in coverage. Each individual’s aggregate dataset recovered 3.4 – 6.4 million bases within variable targeted regions. We uncovered technical variability (2-5 %) inherent to WES technique. We also show improved interpretation in assessing clinically important regions that lack interpretation under current conditions, affecting 12–16 of the 56 genes recommended for secondary analysis by American College of Medical Genetics (ACMG). We demonstrate that comparing technical replicate WES datasets and their derived aggregate data can effectively address overall WES genotyping discrepancies. Conclusion We describe a method to evaluate the reproducibility and stochastics in exome library preparation, and delineate the advantages of aggregating the data derived from technical replicates. The implications of this study are directly applicable to improved experimental design and provide an opportunity to rapidly, efficiently, and accurately arrive at reliable candidate nucleotide variants. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2107-y) contains supplementary material, which is available to authorized users.
    BMC Genomics 12/2015; 16(1). DOI:10.1186/s12864-015-2107-y · 3.99 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: Medical diagnosis and molecular or biochemical confirmation typically rely on the knowledge of the clinician. Although this is very difficult in extremely rare diseases, we hypothesized that the recording of patient phenotypes in Human Phenotype Ontology (HPO) terms and computationally ranking putative disease-associated sequence variants improves diagnosis, particularly for patients with atypical clinical profiles. Methods: Using simulated exomes and the National Institutes of Health Undiagnosed Diseases Program (UDP) patient cohort and associated exome sequence, we tested our hypothesis using Exomiser. Exomiser ranks candidate variants based on patient phenotype similarity to (i) known disease-gene phenotypes, (ii) model organism phenotypes of candidate orthologs, and (iii) phenotypes of protein-protein association neighbors. Results: Benchmarking showed Exomiser ranked the causal variant as the top hit in 97% of known disease-gene associations and ranked the correct seeded variant in up to 87% when detectable disease-gene associations were unavailable. Using UDP data, Exomiser ranked the causative variant(s) within the top 10 variants for 11 previously diagnosed variants and achieved a diagnosis for 4 of 23 cases undiagnosed by clinical evaluation. Conclusion: Structured phenotyping of patients and computational analysis are effective adjuncts for diagnosing patients with genetic disorders.Genet Med advance online publication 12 November 2015Genetics in Medicine (2015); doi:10.1038/gim.2015.137.
    Genetics in medicine: official journal of the American College of Medical Genetics 11/2015; DOI:10.1038/gim.2015.137 · 7.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Chediak-Higashi syndrome (CHS; OMIM no. 214500) is an inherited multisystem disorder presenting with hypopigmentation and a propensity to infections due to immunological dysfunction. CHS generally presents in infancy with a fatal outcome, but less severe cases can present in adulthood. Treatment with bone marrow transplantation can be life-saving, so establishing a correct diagnosis is critical. The presence of large granules on examination of peripheral blood smears is suggestive of the diagnosis of CHS in most centers. However, sequencing of the lysosomal trafficking, LYST, gene confirms the diagnosis and can provide a prognosis regarding disease severity. In the case presented here, we performed molecular testing to identify the causative mutation and tabulated published mutation data from 2009 to 2014. We found a novel frameshift mutation in our case and concluded that frameshift and nonsense are the most common types of mutation in CHS, but this may be biased due to underdiagnosis of the milder and atypical forms of the disease.
    International journal of dermatology 10/2015; DOI:10.1111/ijd.13019 · 1.31 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: Mutations in lysosomal trafficking regulator (LYST) cause Chediak-Higashi syndrome (CHS), a rare immunodeficiency with impaired cytotoxic lymphocyte function, mainly that of natural killer (NK) cells. Our understanding of NK cell function deficiency in patients with CHS and how LYST regulates lytic granule exocytosis is very limited. Objective: We sought to delineate cellular defects associated with LYST mutations responsible for the impaired NK cell function seen in patients with CHS. Methods: We analyzed NK cells from patients with CHS with missense mutations in the LYST ARM/HEAT (armadillo/huntingtin, elongation factor 3, protein phosphatase 2A, and the yeast kinase TOR1) or BEACH (beige and Chediak-Higashi) domains. Results: NK cells from patients with CHS displayed severely reduced cytotoxicity. Mutations in the ARM/HEAT domain led to a reduced number of perforin-containing granules, which were significantly increased in size but able to polarize to the immunologic synapse; however, they were unable to properly fuse with the plasma membrane. Mutations in the BEACH domain resulted in formation of normal or slightly enlarged granules that had markedly impaired polarization to the IS but could be exocytosed on reaching the immunologic synapse. Perforin-containing granules in NK cells from patients with CHS did not acquire certain lysosomal markers (lysosome-associated membrane protein 1/2) but were positive for markers of transport vesicles (cation-independent mannose 6-phosphate receptor), late endosomes (Ras-associated binding protein 27a), and, to some extent, early endosomes (early endosome antigen 1), indicating a lack of integrity in the endolysosomal compartments. NK cells from patients with CHS had normal cytokine compartments and cytokine secretion. Conclusion: LYST is involved in regulation of multiple aspects of NK cell lytic activity, ranging from governance of lytic granule size to control of their polarization and exocytosis, as well as regulation of endolysosomal compartment identity. LYST functions in the regulated exocytosis but not in the constitutive secretion pathway.
    The Journal of allergy and clinical immunology 10/2015; DOI:10.1016/j.jaci.2015.08.039 · 11.48 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: In chicken, loss of TALPID3 results in non-functional cilia and short-rib polydactyly syndrome. This phenotype is caused by a frameshift mutation in the chicken ortholog of the human KIAA0586 gene, which encodes a novel coiled-coil domain protein essential for primary ciliogenesis, suggesting that KIAA0586 can be associated with ciliopathy in human beings. Methods: In our patients with ciliopathy (http://www.clinicaltrials.gov: NCT00068224), we have collected extensive clinical and neuroimaging data from affected individuals, and performed whole exome sequencing on DNA from affected individuals and their parents. We analysed gene expression on fibroblast cell line, and determined the effect of gene mutation on ciliogenesis in cells derived from patients. Results: We identified biallelic mutations in the human TALPID3 ortholog, KIAA0586, in six children with findings of overlapping Jeune and Joubert syndromes. Fibroblasts cultured from one of the patients with Jeune-Joubert syndrome exhibited more severe cilia defects than fibroblasts from patients with only Joubert syndrome; this difference was reflected in KIAA0586 RNA expression levels. Rescue of the cilia defect with full-length wild type KIAA0586 indicated a causal link between cilia formation and KIAA0586 function. Conclusions: Our results show that biallelic deleterious mutations in KIAA0586 lead to Joubert syndrome with or without Jeune asphyxiating thoracic dystrophy. Furthermore, our results confirm that KIAA0586/TALPID3 is essential in cilia formation in human beings, expand the KIAA0586 phenotype to include features of Jeune syndrome and provide a pathogenetic connection between Joubert and Jeune syndromes, based on aberrant ciliogenesis.
    Journal of Medical Genetics 09/2015; DOI:10.1136/jmedgenet-2015-103316 · 6.34 Impact Factor
  • Source

    Mitochondrion 09/2015; 24:S43-S44. DOI:10.1016/j.mito.2015.07.120 · 3.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The musculocontractural type of Ehlers-Danlos syndrome (MC-EDS) has been recently recognized as a clinical entity. MC-EDS represents a differential diagnosis within the congenital neuromuscular and connective tissue disorders spectrum. Thirty-one and three patients have been reported with MC-EDS so far with bi-allelic mutations identified in CHST14 and DSE, respectively, encoding two enzymes necessary for dermatan sulfate (DS) biosynthesis. We report seven additional patients with MC-EDS from four unrelated families, including the follow-up of a sib-pair originally reported with the kyphoscoliotic type of EDS in 1975. Brachycephaly, a characteristic facial appearance, an asthenic build, hyperextensible and bruisable skin, tapering fingers, instability of large joints, and recurrent formation of large subcutaneous hematomas are always present. Three of seven patients had mildly elevated serum creatine kinase. The oldest patient was blind due to retinal detachment at 45 years and died at 59 years from intracranial bleeding; her affected brother died at 28 years from fulminant endocarditis. All patients in this series harbored homozygous, predicted loss-of-function CHST14 mutations. Indeed, DS was not detectable in fibroblasts from two unrelated patients with homozygous mutations. Patient fibroblasts produced higher amounts of chondroitin sulfate, showed intracellular retention of collagen types I and III, and lacked decorin and thrombospondin fibrils compared with control. A great proportion of collagen fibrils were not integrated into fibers, and fiber bundles were dispersed into the ground substance in one patient, all of which is likely to contribute to the clinical phenotype. This report should increase awareness for MC-EDS. © 2015 Wiley Periodicals, Inc.
    American Journal of Medical Genetics Part A 09/2015; DOI:10.1002/ajmg.a.37383 · 2.16 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The discovery of disease-causing mutations typically requires confirmation of the variant or gene in multiple unrelated individuals, and a large number of rare genetic diseases remain unsolved due to difficulty identifying second families. To enable the secure sharing of case records by clinicians and rare disease scientists, we have developed the PhenomeCentral portal (https://phenomecentral.org). Each record includes a phenotypic description and relevant genetic information (exome or candidate genes). PhenomeCentral identifies similar patients in the database based on semantic similarity between clinical features, automatically prioritized genes from whole-exome data, and candidate genes entered by the users, enabling both hypothesis-free and hypothesis-driven matchmaking. Users can then contact other submitters to follow up on promising matches. PhenomeCentral incorporates data for over 1,000 patients with rare genetic diseases, contributed by the FORGE and Care4Rare Canada projects, the US NIH Undiagnosed Diseases Program, the EU Neuromics and ANDDIrare projects, as well as numerous independent clinicians and scientists. Though the majority of these records have associated exome data, most lack a molecular diagnosis. PhenomeCentral has already been used to identify causative mutations for several patients, and its ability to find matching patients and diagnose these diseases will grow with each additional patient that is entered. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Human Mutation 08/2015; 36(10). DOI:10.1002/humu.22851 · 5.14 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Induced pluripotent stem cells (iPSCs) are an essential tool for modeling how causal genetic variants impact cellular function in disease, as well as an emerging source of tissue for regenerative medicine. The preparation of somatic cells, their reprogramming and the subsequent verification of iPSC pluripotency are laborious, manual processes limiting the scale and reproducibility of this technology. Here we describe a modular, robotic platform for iPSC reprogramming enabling automated, high-throughput conversion of skin biopsies into iPSCs and differentiated cells with minimal manual intervention. We demonstrate that automated reprogramming and the pooled selection of polyclonal pluripotent cells results in high-quality, stable iPSCs. These lines display less line-to-line variation than either manually produced lines or lines produced through automation followed by single-colony subcloning. The robotic platform we describe will enable the application of iPSCs to population-scale biomedical problems including the study of complex genetic diseases and the development of personalized medicines.
    Nature Methods 08/2015; 12(9). DOI:10.1038/nmeth.3507 · 32.07 Impact Factor

  • 07/2015; 2(3):342-357. DOI:10.3390/children2030342
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: N-acetylneuraminic acid (Neu5Ac or NANA) is the most predominant sialic acid in mammals. As a terminal component in many glycoproteins and glycolipids, sialic acid is believed to be an important biomarker related to various diseases. Its precursor, N-acetylmannosamine (ManNAc), is being investigated as a potential treatment for GNE myopathy. In this work, we developed two highly sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods for the quantitation of ManNAc and free Neu5Ac in human plasma. A fit-for-purpose approach was adopted during method validation and sample analysis. To measure the endogenous compounds and overcome the interference from plasma samples, a surrogate matrix that contained 5% bovine serum albumin (BSA) was used for the preparation of calibration standards and certain levels of quality control (QC) samples. QC samples at higher concentrations were prepared in the authentic matrix (human plasma) to best mimic incurred samples. For both methods, an Ostro 96-well phospholipid removal plate was used for sample extraction, which efficiently removed the phospholipids from the plasma samples prior to LC injection, eliminated matrix effect, and improved sensitivity. Chromatographic separation was achieved using hydrophilic interaction chromatography (HILIC) and gradient elution in order to retain the two polar compounds. The lower limit of quantitation (LLOQ) for ManNAc and Neu5Ac was 10.0 and 25.0ng/mL, respectively. The overall accuracy of the two assays was within 100%±8.3% based on three levels of QC samples. Inter- and intra-run precision (coefficient of variation (%CV)) across three analytical runs was less than 6.7% for ManNAc and less than 10.8% for Neu5Ac. These methods have been validated to support clinical studies. Copyright © 2015 Elsevier B.V. All rights reserved.
    Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 07/2015; 1000:105-111. DOI:10.1016/j.jchromb.2015.07.018 · 2.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Ablepharon macrostomia syndrome (AMS) and Barber-Say syndrome (BSS) are rare congenital ectodermal dysplasias characterized by similar clinical features. To establish the genetic basis of AMS and BSS, we performed extensive clinical phenotyping, whole exome and candidate gene sequencing, and functional validations. We identified a recurrent de novo mutation in TWIST2 in seven independent AMS-affected families, as well as another recurrent de novo mutation affecting the same amino acid in ten independent BSS-affected families. Moreover, a genotype-phenotype correlation was observed, because the two syndromes differed based solely upon the nature of the substituting amino acid: a lysine at TWIST2 residue 75 resulted in AMS, whereas a glutamine or alanine yielded BSS. TWIST2 encodes a basic helix-loop-helix transcription factor that regulates the development of mesenchymal tissues. All identified mutations fell in the basic domain of TWIST2 and altered the DNA-binding pattern of Flag-TWIST2 in HeLa cells. Comparison of wild-type and mutant TWIST2 expressed in zebrafish identified abnormal developmental phenotypes and widespread transcriptome changes. Our results suggest that autosomal-dominant TWIST2 mutations cause AMS or BSS by inducing protean effects on the transcription factor's DNA binding. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.
    The American Journal of Human Genetics 07/2015; 97(2):99-110. DOI:10.1016/j.ajhg.2015.05.017 · 10.93 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hermansky-Pudlak syndrome (HPS) comprises a group of inherited disorders caused by mutations that alter the function of lysosome-related organelles. Pulmonary fibrosis is the major cause of morbidity and mortality in patients with subtypes HPS-1 and HPS-4, which both result from defects in biogenesis of lysosome-related organelle complex 3 (BLOC-3). The prototypic chitinase-like protein chitinase 3-like-1 (CHI3L1) plays a protective role in the lung by ameliorating cell death and stimulating fibroproliferative repair. Here, we demonstrated that circulating CHI3L1 levels are higher in HPS patients with pulmonary fibrosis compared with those who remain fibrosis free, and that these levels associate with disease severity. Using murine HPS models, we also determined that these animals have a defect in the ability of CHI3L1 to inhibit epithelial apoptosis but exhibit exaggerated CHI3L1-driven fibroproliferation, which together promote HPS fibrosis. These divergent responses resulted from differences in the trafficking and effector functions of two CHI3L1 receptors. Specifically, the enhanced sensitivity to apoptosis was due to abnormal localization of IL-13Rα2 as a consequence of dysfunctional BLOC-3-dependent membrane trafficking. In contrast, the fibrosis was due to interactions between CHI3L1 and the receptor CRTH2, which trafficked normally in BLOC-3 mutant HPS. These data demonstrate that CHI3L1-dependent pathways exacerbate pulmonary fibrosis and suggest CHI3L1 as a potential biomarker for pulmonary fibrosis progression and severity in HPS.
    The Journal of clinical investigation 06/2015; 125(8). DOI:10.1172/JCI79792 · 13.22 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: PIGT-CDG, an autosomal recessive syndromic intellectual disability disorder of glycosylphosphatidylinositol (GPI) anchors, was recently described in two independent kindreds [Multiple Congenital Anomalies-Hypotonia-Seizures Syndrome 3 (OMIM, #615398)]. PIGT encodes phosphatidylinositol-glycan biosynthesis class T, a subunit of the heteropentameric transamidase complex that facilitates the transfer of GPI to proteins. GPI facilitates attachment (anchoring) of proteins to cell membranes. We describe, at ages 7 and 6years, two children of non-consanguineous parents; they had hypotonia, severe global developmental delay, and intractable seizures along with endocrine, ophthalmologic, skeletal, hearing, and cardiac anomalies. Exome sequencing revealed that both siblings had compound heterozygous variants in PIGT (NM_015937.5), i.e., c.918dupC, a novel duplication leading to a frameshift, and c.1342C>T encoding a previously described missense variant. Flow cytometry studies showed decreased surface expression of GPI-anchored proteins on granulocytes, consistent with findings in previous cases. These siblings further delineate the clinical spectrum of PIGT-CDG, reemphasize the neuro-ophthalmologic presentation, clarify the endocrine features, and add hypermobility, low CSF albumin quotient, and hearing loss to the phenotypic spectrum. Our results emphasize that GPI anchor-related congenital disorders of glycosylation (CDGs) should be considered in subjects with early onset severe seizure disorders and dysmorphic facial features, even in the presence of a normal carbohydrate-deficient transferrin pattern and N-glycan profiling. Currently available screening for CDGs will not reliably detect this family of disorders, and our case reaffirms that the use of flow cytometry and genetic testing is essential for diagnosis in this group of disorders. Copyright © 2015. Published by Elsevier Inc.
    Molecular Genetics and Metabolism 05/2015; 115(2-3). DOI:10.1016/j.ymgme.2015.04.007 · 2.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Intellectual disability (ID) is a heterogeneous condition arising from a variety of environmental and genetic factors. Among these causes are defects in transcriptional regulators. Herein, we report on two brothers in a nonconsanguineous family with novel compound heterozygous, disease-segregating mutations (NM_015979.3: [3656A > G];[4006C > T], NP_057063.2: [H1219R];[R1336X]) in MED23. This gene encodes a subunit of the Mediator complex that modulates the expression of RNA polymerase II-dependent genes. These brothers, who had profound ID, spasticity, congenital heart disease, brain abnormalities, and atypical electroencephalography, represent the first case of MED23-associated ID in a non-consanguineous family. They also expand upon the clinical features previously reported for mutations in this gene. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.
    American Journal of Medical Genetics Part A 04/2015; 167(6). DOI:10.1002/ajmg.a.37047 · 2.16 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Snyder-Robinson Syndrome (SRS) is an X-linked intellectual disability disorder also characterized by osteoporosis, scoliosis, and dysmorphic facial features. It is caused by mutations in SMS, a ubiquitously expressed gene encoding the polyamine biosynthetic enzyme spermine synthase. We hypothesized that the tissue specificity of SRS arises from differential sensitivity to spermidine toxicity or spermine deficiency. We performed detailed clinical, endocrine, histopathologic, and morphometric studies on two affected brothers with a spermine synthase loss of function mutation (NM_004595.4:c.443A > G, p.Gln148Arg). We also measured spermine and spermidine levels in cultured human bone marrow stromal cells (hBMSCs) and fibroblasts using the Biochrom 30 polyamine protocol and assessed the osteogenic potential of hBMSCs. In addition to the known tissue-specific features of SRS, the propositi manifested retinal pigmentary changes, recurrent episodes of hyper- and hypoglycemia, nephrocalcinosis, renal cysts, and frequent respiratory infections. Bone histopathology and morphometry identified a profound depletion of osteoblasts and osteoclasts, absence of a trabecular meshwork, a low bone volume and a thin cortex. Comparison of cultured fibroblasts from affected and unaffected individuals showed relatively small changes in polyamine content, whereas comparison of cultured osteoblasts identified marked differences in spermidine and spermine content. Osteogenic differentiation of the SRS-derived hBMSCs identified a severe deficiency of calcium phosphate mineralization. Our findings support the hypothesis that cell specific alterations in polyamine metabolism contribute to the tissue specificity of SRS features, and that the low bone density arises from a failure of mineralization.
    Orphanet Journal of Rare Diseases 03/2015; 10(1):27. DOI:10.1186/s13023-015-0235-8 · 3.36 Impact Factor
  • William A. Gahl ·

    38th Annual Meeting of the Society-for-Inherited-Metabolic-Disorders; 03/2015

  • 38th Annual Meeting of the Society-for-Inherited-Metabolic-Disorders; 03/2015

  • 38th Annual Meeting of the Society-for-Inherited-Metabolic-Disorders; 03/2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In mitochondria, carbamoyl phosphate synthetase 1 activity produces carbamoyl phosphate for urea synthesis, and deficiency results in hyperammonemia. Cytoplasmic carbamoyl phosphate synthetase 2, however, is part of a tri-functional enzyme encoded by CAD; no human disease has been attributed to this gene. The tri-functional enzyme contains carbamoyl-phosphate synthetase 2 (CPS2), aspartate transcarbamylase (ATCase), and dihydroorotase (DHOase) activities, which comprise the first three of six reactions required for de novo pyrimidine biosynthesis. Here we characterize an individual who is compound heterozygous for mutations in different domains of CAD. One mutation, c.1843-1G>A, results in an in-frame deletion of exon thirteen. The other, c.6071G>A, causes a missense mutation (p.Arg2024Gln) in a highly conserved residue that is essential for carbamoyl-phosphate binding. Metabolic flux studies showed impaired aspartate incorporation into RNA and DNA through the de novo synthesis pathway. In addition, CTP, UTP, and nearly all UDP-activated sugars that serve as donors for glycosylation were decreased. Uridine supplementation rescued these abnormalities, suggesting a potential therapy for this new glycosylation disorder. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Human Molecular Genetics 02/2015; 24(11). DOI:10.1093/hmg/ddv057 · 6.39 Impact Factor

Publication Stats

13k Citations
3,442.38 Total Impact Points


  • 2015
    • Johannes Gutenberg-Universität Mainz
      Mayence, Rheinland-Pfalz, Germany
  • 2002-2015
    • National Human Genome Research Institute
      베서스다, Maryland, United States
  • 2014
    • State of Maryland
      Maryland City, Maryland, United States
  • 1984-2014
    • National Institutes of Health
      • • Branch of Neurogenetics
      • • Office of Rare Diseases Research
      • • Rehabilitation Medicine Department
      • • Section on Human Genetics
      • • Cell Biology and Metabolism Program
      • • Branch of Genetics
      • • Laboratory of Cellular and Molecular Biology
      • • Center for Clinical Research
      Maryland, United States
  • 2001-2013
    • Northern Inyo Hospital
      BIH, California, United States
    • University of Cincinnati
      • Department of Dermatology
      Cincinnati, Ohio, United States
  • 2011
    • National Heart, Lung, and Blood Institute
      베서스다, Maryland, United States
  • 2010
    • University of Alabama at Birmingham
      Birmingham, Alabama, United States
  • 2005-2009
    • Great Ormond Street Hospital for Children NHS Foundation Trust
      Londinium, England, United Kingdom
    • Sheba Medical Center
      Gan, Tel Aviv, Israel
  • 1988-2009
    • National Eye Institute
      베서스다, Maryland, United States
    • IT University of Copenhagen
      København, Capital Region, Denmark
    • The Ohio State University
      • Department of Obstetrics and Gynecology
      Columbus, OH, United States
    • University of Helsinki
      Helsinki, Uusimaa, Finland
  • 2006
    • George Washington University
      Washington, Washington, D.C., United States
  • 1997-2005
    • National Institute of Mental Health (NIMH)
      • Clinical Neuroscience Research Branch
      베서스다, Maryland, United States
  • 2003
    • University of Maryland, Baltimore
      Baltimore, Maryland, United States
    • Brown University
      Providence, Rhode Island, United States
  • 1984-2003
    • National Institute of Child Health and Human Development
      Maryland, United States
  • 1995-1999
    • Eunice Kennedy Shriver National Institute of Child Health and Human Development
      Роквилл, Maryland, United States
    • The University of Sheffield
      Sheffield, England, United Kingdom
    • University of Oslo
      Kristiania (historical), Oslo County, Norway
  • 1984-1999
    • University of California, San Diego
      • • Department of Pediatrics
      • • Department of Medicine
      San Diego, California, United States
  • 1993
    • Thomas Jefferson University
      Filadelfia, Pennsylvania, United States
    • National Institute on Aging
      • Laboratory of Neurosciences (LNS)
      Baltimore, Maryland, United States
  • 1989-1992
    • Johns Hopkins University
      • • Department of Pathology
      • • Department of Pediatrics
      Baltimore, Maryland, United States
  • 1989-1990
    • The National Institute of Diabetes and Digestive and Kidney Diseases
      베서스다, Maryland, United States
  • 1987-1989
    • Wayne State University
      Detroit, Michigan, United States
    • Radboud University Nijmegen
      Nymegen, Gelderland, Netherlands
    • NEI Corporation
      Сомерсет, New Jersey, United States
  • 1987-1988
    • Johns Hopkins Medicine
      Baltimore, Maryland, United States