@article {357, title = {Lessons learned from additional research analyses of unsolved clinical exome cases.}, journal = {Genome Med}, volume = {9}, year = {2017}, month = {2017 03 21}, pages = {26}, abstract = {

BACKGROUND: Given the rarity of most single-gene Mendelian disorders, concerted efforts of data exchange between clinical and scientific communities are critical to optimize molecular diagnosis and novel disease gene discovery.

METHODS: We designed and implemented protocols for the study of cases for which a plausible molecular diagnosis was not achieved in a clinical genomics diagnostic laboratory (i.e. unsolved clinical exomes). Such cases were recruited to a research laboratory for further analyses, in order to potentially: (1) accelerate novel disease gene discovery; (2) increase the molecular diagnostic yield of whole exome sequencing (WES); and (3) gain insight into the genetic mechanisms of disease. Pilot project data included 74 families, consisting mostly of parent-offspring trios. Analyses performed on a research basis employed both WES from additional family members and complementary bioinformatics approaches and protocols.

RESULTS: Analysis of all possible modes of Mendelian inheritance, focusing on both single nucleotide variants (SNV) and copy number variant (CNV) alleles, yielded a likely contributory variant in 36\% (27/74) of cases. If one includes candidate genes with variants identified within a single family, a potential contributory variant was identified in a total of ~51\% (38/74) of cases enrolled in this pilot study. The molecular diagnosis was achieved in 30/63 trios (47.6\%). Besides this, the analysis workflow yielded evidence for pathogenic variants in disease-associated genes in 4/6 singleton cases (66.6\%), 1/1 multiplex family involving three affected siblings, and 3/4 (75\%) quartet families. Both the analytical pipeline and the collaborative efforts between the diagnostic and research laboratories provided insights that allowed recent disease gene discoveries (PURA, TANGO2, EMC1, GNB5, ATAD3A, and MIPEP) and increased the number of novel genes, defined in this study as genes identified in more than one family (DHX30 and EBF3).

CONCLUSION: An efficient genomics pipeline in which clinical sequencing in a diagnostic laboratory is followed by the detailed reanalysis of unsolved cases in a research environment, supplemented with WES data from additional family members, and subject to adjuvant bioinformatics analyses including relaxed variant filtering parameters in informatics pipelines, can enhance the molecular diagnostic yield and provide mechanistic insights into Mendelian disorders. Implementing these approaches requires collaborative clinical molecular diagnostic and research efforts.

}, keywords = {Adenosine Triphosphatases, ATPases Associated with Diverse Cellular Activities, Computational Biology, DNA Copy Number Variations, DNA-Binding Proteins, Exome, Female, Genetic Diseases, Inborn, Genomics, GTP-Binding Protein beta Subunits, Humans, Male, Membrane Proteins, Metalloendopeptidases, Mitochondrial Proteins, Pilot Projects, Polymorphism, Single Nucleotide, Sequence Analysis, DNA, Transcription Factors}, issn = {1756-994X}, doi = {10.1186/s13073-017-0412-6}, author = {Eldomery, Mohammad K and Coban-Akdemir, Zeynep and Harel, Tamar and Rosenfeld, Jill A and Gambin, Tomasz and Stray-Pedersen, Asbj{\o}rg and K{\"u}ry, S{\'e}bastien and Mercier, Sandra and Lessel, Davor and Denecke, Jonas and Wiszniewski, Wojciech and Penney, Samantha and Liu, Pengfei and Bi, Weimin and Lalani, Seema R and Schaaf, Christian P and Wangler, Michael F and Bacino, Carlos A and Lewis, Richard Alan and Potocki, Lorraine and Graham, Brett H and Belmont, John W and Scaglia, Fernando and Orange, Jordan S and Jhangiani, Shalini N and Chiang, Theodore and Doddapaneni, Harsha and Hu, Jianhong and Muzny, Donna M and Xia, Fan and Beaudet, Arthur L and Boerwinkle, Eric and Eng, Christine M and Plon, Sharon E and Sutton, V Reid and Gibbs, Richard A and Posey, Jennifer E and Yang, Yaping and Lupski, James R} } @article {10, title = {MIPEP recessive variants cause a syndrome of left ventricular non-compaction, hypotonia, and infantile death.}, journal = {Genome Med}, volume = {8}, year = {2016}, month = {2016 Nov 01}, pages = {106}, abstract = {

BACKGROUND: Mitochondrial presequence proteases perform fundamental functions as they process about 70~\% of all mitochondrial preproteins that are encoded in the nucleus and imported posttranslationally. The mitochondrial intermediate presequence protease MIP/Oct1, which carries out precursor processing, has not yet been established to have a role in human disease.

METHODS: Whole exome sequencing was performed on four unrelated probands with left ventricular non-compaction (LVNC), developmental delay (DD), seizures, and severe hypotonia. Proposed pathogenic variants were confirmed by Sanger sequencing or array comparative genomic hybridization. Functional analysis of the identified MIP variants was performed using the model organism Saccharomyces cerevisiae as the protein and its functions are highly conserved from yeast to human.

RESULTS: Biallelic single nucleotide variants (SNVs) or copy number variants (CNVs) in MIPEP, which encodes MIP, were present in all four probands, three of whom had infantile/childhood death. Two patients had compound heterozygous SNVs (p.L582R/p.L71Q and p.E602*/p.L306F) and one patient from a consanguineous family had a homozygous SNV (p.K343E). The fourth patient, identified through the GeneMatcher tool, a part of the Matchmaker Exchange Project, was found to have inherited a paternal SNV (p.H512D) and a maternal CNV (1.4-Mb deletion of 13q12.12) that includes MIPEP. All amino acids affected in the patients{\textquoteright} missense variants are highly conserved from yeast to human and therefore S. cerevisiae was employed for functional analysis (for p.L71Q, p.L306F, and p.K343E). The mutations p.L339F (human p.L306F) and p.K376E (human p.K343E) resulted in a severe decrease of Oct1 protease activity and accumulation of non-processed Oct1 substrates and consequently impaired viability under respiratory growth conditions. The p.L83Q (human p.L71Q) failed to localize to the mitochondria.

CONCLUSIONS: Our findings reveal for the first time the role of the mitochondrial intermediate peptidase in human disease. Loss of MIP function results in a syndrome which consists of LVNC, DD, seizures, hypotonia, and cataracts. Our approach highlights the power of data exchange and the importance of an interrelationship between clinical and research efforts for disease gene discovery.

}, keywords = {Adult, Amino Acid Sequence, Female, Genes, Recessive, Heart Defects, Congenital, Humans, Infant, Infant, Newborn, Male, Metalloendopeptidases, Muscle Hypotonia, Pedigree, Phenotype, Sequence Homology, Amino Acid, Sudden Infant Death, Syndrome}, issn = {1756-994X}, doi = {10.1186/s13073-016-0360-6}, author = {Eldomery, Mohammad K and Akdemir, Zeynep C and V{\"o}gtle, F-Nora and Charng, Wu-Lin and Mulica, Patrycja and Rosenfeld, Jill A and Gambin, Tomasz and Gu, Shen and Burrage, Lindsay C and Al Shamsi, Aisha and Penney, Samantha and Jhangiani, Shalini N and Zimmerman, Holly H and Muzny, Donna M and Wang, Xia and Tang, Jia and Medikonda, Ravi and Ramachandran, Prasanna V and Wong, Lee-Jun and Boerwinkle, Eric and Gibbs, Richard A and Eng, Christine M and Lalani, Seema R and Hertecant, Jozef and Rodenburg, Richard J and Abdul-Rahman, Omar A and Yang, Yaping and Xia, Fan and Wang, Meng C and Lupski, James R and Meisinger, Chris and Sutton, V Reid} } @article {173, title = {COPA mutations impair ER-Golgi transport and cause hereditary autoimmune-mediated lung disease and arthritis.}, journal = {Nat Genet}, volume = {47}, year = {2015}, month = {2015 Jun}, pages = {654-60}, abstract = {

Unbiased genetic studies have uncovered surprising molecular mechanisms in human cellular immunity and autoimmunity. We performed whole-exome sequencing and targeted sequencing in five families with an apparent mendelian syndrome of autoimmunity characterized by high-titer autoantibodies, inflammatory arthritis and interstitial lung disease. We identified four unique deleterious variants in the COPA gene (encoding coatomer subunit α) affecting the same functional domain. Hypothesizing that mutant COPA leads to defective intracellular transport via coat protein complex I (COPI), we show that COPA variants impair binding to proteins targeted for retrograde Golgi-to-ER transport. Additionally, expression of mutant COPA results in ER stress and the upregulation of cytokines priming for a T helper type 17 (TH17) response. Patient-derived CD4(+) T cells also demonstrate significant skewing toward a TH17 phenotype that is implicated in autoimmunity. Our findings uncover an unexpected molecular link between a vesicular transport protein and a syndrome of autoimmunity manifested by lung and joint disease.

}, keywords = {Amino Acid Sequence, Arthritis, Autoimmune Diseases, Child, Preschool, Coatomer Protein, Endoplasmic Reticulum, Endoplasmic Reticulum Stress, Female, Genetic Association Studies, Genetic Predisposition to Disease, Golgi Apparatus, HEK293 Cells, Humans, Infant, Lod Score, Lung Diseases, Interstitial, Male, Molecular Sequence Data, Pedigree, Protein Transport}, issn = {1546-1718}, doi = {10.1038/ng.3279}, author = {Watkin, Levi B and Jessen, Birthe and Wiszniewski, Wojciech and Vece, Timothy J and Jan, Max and Sha, Youbao and Thamsen, Maike and Santos-Cortez, Regie L P and Lee, Kwanghyuk and Gambin, Tomasz and Forbes, Lisa R and Law, Christopher S and Stray-Pedersen, Asbj{\o}rg and Cheng, Mickie H and Mace, Emily M and Anderson, Mark S and Liu, Dongfang and Tang, Ling Fung and Nicholas, Sarah K and Nahmod, Karen and Makedonas, George and Canter, Debra L and Kwok, Pui-Yan and Hicks, John and Jones, Kirk D and Penney, Samantha and Jhangiani, Shalini N and Rosenblum, Michael D and Dell, Sharon D and Waterfield, Michael R and Papa, Feroz R and Muzny, Donna M and Zaitlen, Noah and Leal, Suzanne M and Gonzaga-Jauregui, Claudia and Boerwinkle, Eric and Eissa, N Tony and Gibbs, Richard A and Lupski, James R and Orange, Jordan S and Shum, Anthony K} } @article {183, title = {DVL1 frameshift mutations clustering in the penultimate exon cause autosomal-dominant Robinow syndrome.}, journal = {Am J Hum Genet}, volume = {96}, year = {2015}, month = {2015 Apr 02}, pages = {612-22}, abstract = {

Robinow syndrome is a genetically heterogeneous disorder characterized by mesomelic limb shortening, genital hypoplasia, and distinctive facial features and for which both autosomal-recessive and autosomal-dominant inheritance patterns have been described. Causative variants in the non-canonical signaling gene WNT5A underlie a subset of autosomal-dominant Robinow syndrome (DRS) cases, but most individuals with DRS remain without a molecular diagnosis. We performed whole-exome sequencing in four unrelated DRS-affected individuals without coding mutations in WNT5A and found heterozygous DVL1 exon 14 mutations in three of them. Targeted Sanger sequencing in additional subjects with DRS uncovered DVL1 exon 14 mutations in five individuals, including a pair of monozygotic twins. In total, six distinct frameshift mutations were found in eight subjects, and all were heterozygous truncating variants within the penultimate exon of DVL1. In five families in which samples from unaffected parents were available, the variants were demonstrated to represent de novo mutations. All variant alleles are predicted to result in a premature termination codon within the last exon, escape nonsense-mediated decay (NMD), and most likely generate a C-terminally truncated protein with a distinct -1 reading-frame terminus. Study of the transcripts extracted from affected subjects{\textquoteright} leukocytes confirmed expression of both wild-type and variant alleles, supporting the hypothesis that mutant mRNA escapes NMD. Genomic variants identified in our study suggest that truncation of the C-terminal domain of DVL1, a protein hypothesized to have a downstream role in the Wnt-5a non-canonical pathway, is a common cause of DRS.

}, keywords = {Adaptor Proteins, Signal Transducing, Amino Acid Sequence, Base Sequence, Craniofacial Abnormalities, Dishevelled Proteins, DNA Primers, Dwarfism, Exome, Exons, Frameshift Mutation, Gene Components, Humans, Limb Deformities, Congenital, Molecular Sequence Data, Phosphoproteins, Sequence Analysis, DNA, Urogenital Abnormalities}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2015.02.015}, author = {White, Janson and Mazzeu, Juliana F and Hoischen, Alexander and Jhangiani, Shalini N and Gambin, Tomasz and Alcino, Michele Calijorne and Penney, Samantha and Saraiva, Jorge M and Hove, Hanne and Skovby, Flemming and Kayserili, H{\"u}lya and Estrella, Elicia and Vulto-van Silfhout, Anneke T and Steehouwer, Marloes and Muzny, Donna M and Sutton, V Reid and Gibbs, Richard A and Lupski, James R and Brunner, Han G and van Bon, Bregje W M and Carvalho, Claudia M B} } @article {237, title = {Mutations in COL27A1 cause Steel syndrome and suggest a founder mutation effect in the Puerto Rican population.}, journal = {Eur J Hum Genet}, volume = {23}, year = {2015}, month = {2015 Mar}, pages = {342-6}, abstract = {

Osteochondrodysplasias represent a large group of developmental structural disorders that can be caused by mutations in a variety of genes responsible for chondrocyte development, differentiation, mineralization and early ossification. The application of whole-exome sequencing to disorders apparently segregating as Mendelian traits has proven to be an effective approach to disease gene identification for conditions with unknown molecular etiology. We identified a homozygous missense variant p.(Gly697Arg) in COL27A1, in a family with Steel syndrome and no consanguinity. Interestingly, the identified variant seems to have arisen as a founder mutation in the Puerto Rican population.

}, keywords = {Amino Acid Sequence, Child, Preschool, Comparative Genomic Hybridization, Exome, Female, Fibrillar Collagens, Follow-Up Studies, Founder Effect, Genotype, Hispanic Americans, Humans, Infant, Male, Molecular Sequence Data, Mutation, Osteochondrodysplasias, Pedigree, Polymorphism, Single Nucleotide, Prostaglandins F, Puerto Rico, Sequence Alignment}, issn = {1476-5438}, doi = {10.1038/ejhg.2014.107}, author = {Gonzaga-Jauregui, Claudia and Gamble, Candace N and Yuan, Bo and Penney, Samantha and Jhangiani, Shalini and Muzny, Donna M and Gibbs, Richard A and Lupski, James R and Hecht, Jacqueline T} } @article {143, title = {Secondary findings and carrier test frequencies in a large multiethnic sample.}, journal = {Genome Med}, volume = {7}, year = {2015}, month = {2015}, pages = {54}, abstract = {

BACKGROUND: Besides its growing importance in clinical diagnostics and understanding the genetic basis of Mendelian and complex diseases, whole exome sequencing (WES) is a rich source of additional information of potential clinical utility for physicians, patients and their families. We analyzed the frequency and nature of single nucleotide variants (SNVs) considered secondary findings and recessive disease allele carrier status in the exomes of 8554 individuals from a large, randomly sampled cohort study and 2514 patients from a study of presumed Mendelian disease having undergone WES.

METHODS: We used the same sequencing platform and data processing pipeline to analyze all samples and characterized the distributions of reported pathogenic (ClinVar, Human Gene Mutation Database (HGMD)) and predicted deleterious variants in the pre-specified American College of Medical Genetics and Genomics (ACMG) secondary findings and recessive disease genes in different ethnic groups.

RESULTS: In the 56 ACMG secondary findings genes, the average number of predicted deleterious variants per individual was 0.74, and the mean number of ClinVar reported pathogenic variants was 0.06. We observed an average of 10 deleterious and 0.78 ClinVar reported pathogenic variants per individual in 1423 autosomal recessive disease genes. By repeatedly sampling pairs of exomes, 0.5~\% of the randomly generated couples were at 25~\% risk of having an affected offspring for an autosomal recessive disorder based on the ClinVar variants.

CONCLUSIONS: By investigating reported pathogenic and novel, predicted deleterious variants we estimated the lower and upper limits of the population fraction for which exome sequencing may reveal additional medically relevant information. We suggest that the observed wide range for the lower and upper limits of these frequency numbers will be gradually reduced due to improvement in classification databases and prediction algorithms.

}, issn = {1756-994X}, doi = {10.1186/s13073-015-0171-1}, author = {Gambin, Tomasz and Jhangiani, Shalini N and Below, Jennifer E and Campbell, Ian M and Wiszniewski, Wojciech and Muzny, Donna M and Staples, Jeffrey and Morrison, Alanna C and Bainbridge, Matthew N and Penney, Samantha and McGuire, Amy L and Gibbs, Richard A and Lupski, James R and Boerwinkle, Eric} } @article {251, title = {Clinical utility of whole-exome sequencing in rare diseases: Galactosialidosis.}, journal = {Eur J Med Genet}, volume = {57}, year = {2014}, month = {2014 Jul}, pages = {339-344}, abstract = {

Rare genetic disorders can go undiagnosed for years as the entire spectrum of phenotypic variation is not well characterized given the reduced number of patients reported in the literature and the low frequency at which these occur. Moreover, the current paradigm for clinical diagnostics defines disease diagnosis by a specified spectrum of phenotypic findings; when such parameters are either missing, or other findings not usually observed are seen, the phenotype driven approach to diagnosis may result in a specific etiological diagnosis not even being considered within the differential diagnosis. The novel implementation of genomic sequencing approaches to investigate rare genetic disorders is allowing not only the discovery of new genes, but also the phenotypic expansion of known Mendelian genetic disorders. Here we report the detailed clinical assessment of a patient with a rare genetic disorder with undefined molecular diagnosis. We applied whole-exome sequencing to this patient and unaffected parents in order to identify the molecular cause of her disorder. We identified compound heterozygous mutations in the CTSA gene, responsible for causing galactosialidosis; the molecular diagnosis was further confirmed by biochemical studies. This report expands on the clinical spectrum of this rare lysosomal disorder and exemplifies how genomic approaches are further elucidating the characterization and understanding of genetic diseases.

}, keywords = {Adult, Cathepsin A, Exome, Female, Humans, Lysosomal Storage Diseases, Mutation, Rare Diseases, Sequence Analysis, DNA, Young Adult}, issn = {1878-0849}, doi = {10.1016/j.ejmg.2014.04.005}, author = {Prada, Carlos E and Gonzaga-Jauregui, Claudia and Tannenbaum, Rebecca and Penney, Samantha and Lupski, James R and Hopkin, Robert J and Sutton, V Reid} } @article {220, title = {A drosophila genetic resource of mutants to study mechanisms underlying human genetic diseases.}, journal = {Cell}, volume = {159}, year = {2014}, month = {2014 Sep 25}, pages = {200-214}, abstract = {

Invertebrate model systems are powerful tools for studying human disease owing to their genetic tractability and ease of screening. We conducted a mosaic genetic screen of lethal mutations on the Drosophila X chromosome to identify genes required for the development, function, and maintenance of the nervous system. We identified 165 genes, most of whose function has not been studied in vivo. In parallel, we investigated rare variant alleles in 1,929 human exomes from families with unsolved Mendelian disease. Genes that are essential in flies and have multiple human homologs were found to be likely to be associated with human diseases. Merging the human data sets with the fly genes allowed us to identify disease-associated mutations in six families and to provide insights into microcephaly associated with brain dysgenesis. This bidirectional synergism between fly genetics and human genomics facilitates the functional annotation of evolutionarily conserved genes involved in human health.

}, keywords = {Animals, Disease, Disease Models, Animal, Drosophila melanogaster, Genetic Testing, Humans, Inheritance Patterns, RNA Interference, X Chromosome}, issn = {1097-4172}, doi = {10.1016/j.cell.2014.09.002}, author = {Yamamoto, Shinya and Jaiswal, Manish and Charng, Wu-Lin and Gambin, Tomasz and Karaca, Ender and Mirzaa, Ghayda and Wiszniewski, Wojciech and Sandoval, Hector and Haelterman, Nele A and Xiong, Bo and Zhang, Ke and Bayat, Vafa and David, Gabriela and Li, Tongchao and Chen, Kuchuan and Gala, Upasana and Harel, Tamar and Pehlivan, Davut and Penney, Samantha and Vissers, Lisenka E L M and de Ligt, Joep and Jhangiani, Shalini N and Xie, Yajing and Tsang, Stephen H and Parman, Yesim and Sivaci, Merve and Battaloglu, Esra and Muzny, Donna and Wan, Ying-Wooi and Liu, Zhandong and Lin-Moore, Alexander T and Clark, Robin D and Curry, Cynthia J and Link, Nichole and Schulze, Karen L and Boerwinkle, Eric and Dobyns, William B and Allikmets, Rando and Gibbs, Richard A and Chen, Rui and Lupski, James R and Wangler, Michael F and Bellen, Hugo J} } @article {257, title = {Heterozygous de novo and inherited mutations in the smooth muscle actin (ACTG2) gene underlie megacystis-microcolon-intestinal hypoperistalsis syndrome.}, journal = {PLoS Genet}, volume = {10}, year = {2014}, month = {2014 Mar}, pages = {e1004258}, abstract = {

Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare disorder of enteric smooth muscle function affecting the intestine and bladder. Patients with this severe phenotype are dependent on total parenteral nutrition and urinary catheterization. The cause of this syndrome has remained a mystery since Berdon{\textquoteright}s initial description in 1976. No genes have been clearly linked to MMIHS. We used whole-exome sequencing for gene discovery followed by targeted Sanger sequencing in a cohort of patients with MMIHS and intestinal pseudo-obstruction. We identified heterozygous ACTG2 missense variants in 15 unrelated subjects, ten being apparent de novo mutations. Ten unique variants were detected, of which six affected CpG dinucleotides and resulted in missense mutations at arginine residues, perhaps related to biased usage of CpG containing codons within actin genes. We also found some of the same heterozygous mutations that we observed as apparent de novo mutations in MMIHS segregating in families with intestinal pseudo-obstruction, suggesting that ACTG2 is responsible for a spectrum of smooth muscle disease. ACTG2 encodes γ2 enteric actin and is the first gene to be clearly associated with MMIHS, suggesting an important role for contractile proteins in enteric smooth muscle disease.

}, keywords = {Abnormalities, Multiple, Actins, Adolescent, Adult, Child, Child, Preschool, Colon, Exome, Female, Heterozygote, Humans, Intestinal Pseudo-Obstruction, Male, Muscle, Smooth, Mutation, Urinary Bladder}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1004258}, author = {Wangler, Michael F and Gonzaga-Jauregui, Claudia and Gambin, Tomasz and Penney, Samantha and Moss, Timothy and Chopra, Atul and Probst, Frank J and Xia, Fan and Yang, Yaping and Werlin, Steven and Eglite, Ieva and Kornejeva, Liene and Bacino, Carlos A and Baldridge, Dustin and Neul, Jeff and Lehman, Efrat Lev and Larson, Austin and Beuten, Joke and Muzny, Donna M and Jhangiani, Shalini and Gibbs, Richard A and Lupski, James R and Beaudet, Arthur} } @article {259, title = {Whole-exome sequencing reveals GPIHBP1 mutations in infantile colitis with severe hypertriglyceridemia.}, journal = {J Pediatr Gastroenterol Nutr}, volume = {59}, year = {2014}, month = {2014 Jul}, pages = {17-21}, abstract = {

Severe congenital hypertriglyceridemia (HTG) is a rare disorder caused by mutations in genes affecting lipoprotein lipase (LPL) activity. Here we report a 5-week-old Hispanic girl with severe HTG (12,031 mg/dL, normal limit 150 mg/dL) who presented with the unusual combination of lower gastrointestinal bleeding and milky plasma. Initial colonoscopy was consistent with colitis, which resolved with reduction of triglycerides. After negative sequencing of the LPL gene, whole-exome sequencing revealed novel compound heterozygous mutations in GPIHBP1. Our study broadens the phenotype of GPIHBP1-associated HTG, reinforces the effectiveness of whole-exome sequencing in Mendelian diagnoses, and implicates triglycerides in gastrointestinal mucosal injury.

}, keywords = {Colitis, DNA Mutational Analysis, Exome, Female, Humans, Hypertriglyceridemia, Infant, Receptors, Lipoprotein}, issn = {1536-4801}, doi = {10.1097/MPG.0000000000000363}, author = {Gonzaga-Jauregui, Claudia and Mir, Sabina and Penney, Samantha and Jhangiani, Shalini and Midgen, Craig and Finegold, Milton and Muzny, Donna M and Wang, Min and Bacino, Carlos A and Gibbs, Richard A and Lupski, James R and Kellermayer, Richard and Hanchard, Neil A} } @article {287, title = {Mutations in VRK1 associated with complex motor and sensory axonal neuropathy plus microcephaly.}, journal = {JAMA Neurol}, volume = {70}, year = {2013}, month = {2013 Dec}, pages = {1491-8}, abstract = {

IMPORTANCE: Patients with rare diseases and complex clinical presentations represent a challenge for clinical diagnostics. Genomic approaches are allowing the identification of novel variants in genes for very rare disorders, enabling a molecular diagnosis. Genomics is also revealing a phenotypic expansion whereby the full spectrum of clinical expression conveyed by mutant alleles at a locus can be better appreciated.

OBJECTIVE: To elucidate the molecular cause of a complex neuropathy phenotype in 3 patients by applying genomic sequencing strategies.

DESIGN, SETTING, AND PARTICIPANTS: Three affected individuals from 2 unrelated families presented with a complex neuropathy phenotype characterized by axonal sensorimotor neuropathy and microcephaly. They were recruited into the Centers for Mendelian Genomics research program to identify the molecular cause of their phenotype. Whole-genome, targeted whole-exome sequencing, and high-resolution single-nucleotide polymorphism arrays were performed in genetics clinics of tertiary care pediatric hospitals and biomedical research institutions.

MAIN OUTCOMES AND MEASURES: Whole-genome and whole-exome sequencing identified the variants responsible for the patients{\textquoteright} clinical phenotype.

RESULTS: We identified compound heterozygous alleles in 2 affected siblings from 1 family and a homozygous nonsense variant in the third unrelated patient in the vaccinia-related kinase 1 gene (VRK1). In the latter subject, we found a common haplotype on which the nonsense mutation occurred and that segregates in the Ashkenazi Jewish population.

CONCLUSIONS AND RELEVANCE: We report the identification of disease-causing alleles in 3 children from 2 unrelated families with a previously uncharacterized complex axonal motor and sensory neuropathy accompanied by severe nonprogressive microcephaly and cerebral dysgenesis. Our data raise the question of whether VRK1 mutations disturb cell cycle progression and may result in apoptosis of cells in the nervous system. The application of unbiased genomic approaches allows the identification of potentially pathogenic mutations in unsuspected genes in highly genetically heterogeneous and uncharacterized neurological diseases.

}, keywords = {Child, Child, Preschool, DNA Mutational Analysis, Female, Genotype, Hereditary Sensory and Motor Neuropathy, Humans, Infant, Intracellular Signaling Peptides and Proteins, Magnetic Resonance Imaging, Male, Microcephaly, Mutation, Neural Conduction, Polymorphism, Single Nucleotide, Protein-Serine-Threonine Kinases}, issn = {2168-6157}, doi = {10.1001/jamaneurol.2013.4598}, author = {Gonzaga-Jauregui, Claudia and Lotze, Timothy and Jamal, Leila and Penney, Samantha and Campbell, Ian M and Pehlivan, Davut and Hunter, Jill V and Woodbury, Suzanne L and Raymond, Gerald and Adesina, Adekunle M and Jhangiani, Shalini N and Reid, Jeffrey G and Muzny, Donna M and Boerwinkle, Eric and Lupski, James R and Gibbs, Richard A and Wiszniewski, Wojciech} }