@article {814, title = {Mutations in MYLPF Cause a Novel Segmental Amyoplasia that Manifests as Distal Arthrogryposis.}, journal = {Am J Hum Genet}, volume = {107}, year = {2020}, month = {2020 08 06}, pages = {293-310}, abstract = {

We identified ten persons in six consanguineous families with distal arthrogryposis (DA) who had congenital contractures, scoliosis, and short stature. Exome sequencing revealed that each affected person was homozygous for one of two different rare variants (c.470G>T [p.Cys157Phe] or c.469T>C [p.Cys157Arg]) affecting the same residue of myosin light chain, phosphorylatable, fast skeletal muscle (MYLPF). In a seventh family, a c.487G>A (p.Gly163Ser) variant in MYLPF arose de novo in a father, who transmitted it to his son. In an eighth family comprised of seven individuals with dominantly inherited DA, a c.98C>T (p.Ala33Val) variant segregated in all four persons tested. Variants in MYLPF underlie both dominant and recessively inherited DA. Mylpf protein models suggest that the residues associated with dominant DA interact with myosin whereas the residues altered in families with recessive DA only indirectly impair this interaction. Pathological and histological exam of a foot amputated from an affected child revealed complete absence of skeletal muscle (i.e., segmental amyoplasia). To investigate the mechanism for this finding, we generated an animal model for partial MYLPF impairment by knocking out zebrafish mylpfa. The mylpfa mutant had reduced trunk contractile force and complete pectoral fin paralysis, demonstrating that mylpf impairment most severely affects limb movement. mylpfa mutant muscle weakness was most pronounced in an appendicular muscle and was explained by reduced myosin activity and fiber degeneration. Collectively, our findings demonstrate that partial loss of MYLPF function can lead to congenital contractures, likely as a result of degeneration of skeletal muscle in the distal limb.

}, keywords = {Adolescent, Amino Acid Sequence, Animals, Arthrogryposis, Child, Contracture, Extremities, Female, Humans, Male, Muscle, Skeletal, Musculoskeletal Abnormalities, Mutation, Myosin Light Chains, Myosins, Pedigree, Young Adult, Zebrafish}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2020.06.014}, author = {Chong, Jessica X and Talbot, Jared C and Teets, Emily M and Previs, Samantha and Martin, Brit L and Shively, Kathryn M and Marvin, Colby T and Aylsworth, Arthur S and Saadeh-Haddad, Reem and Schatz, Ulrich A and Inzana, Francesca and Ben-Omran, Tawfeg and Almusafri, Fatima and Al-Mulla, Mariam and Buckingham, Kati J and Harel, Tamar and Mor-Shaked, Hagar and Radhakrishnan, Periyasamy and Girisha, Katta M and Nayak, Shalini S and Shukla, Anju and Dieterich, Klaus and Faure, Julien and Rendu, John and Capri, Yline and Latypova, X{\'e}nia and Nickerson, Deborah A and Warshaw, David M and Janssen, Paul M L and Amacher, Sharon L and Bamshad, Michael J} } @article {424, title = {De Novo Missense Mutations in DHX30 Impair Global Translation and Cause a Neurodevelopmental Disorder.}, journal = {Am J Hum Genet}, volume = {101}, year = {2017}, month = {2017 Nov 02}, pages = {716-724}, abstract = {

DHX30 is a member of the family of DExH-box helicases, which use ATP hydrolysis to unwind RNA secondary structures. Here we identified six different de novo missense mutations in DHX30 in twelve unrelated individuals affected by global developmental delay (GDD), intellectual disability (ID), severe speech impairment and gait abnormalities. While four mutations are recurrent, two are unique with one affecting the codon of one recurrent mutation. All amino acid changes are located within highly conserved helicase motifs and were found to either impair ATPase activity or RNA recognition in different in~vitro assays. Moreover, protein variants exhibit an increased propensity to trigger stress granule (SG) formation resulting in global translation inhibition. Thus, our findings highlight the prominent role of translation control in development and function of the central nervous system and also provide molecular insight into how DHX30 dysfunction might cause a neurodevelopmental disorder.

}, keywords = {Adenosine Triphosphatases, Adolescent, Amino Acids, Cell Line, Cell Line, Tumor, Central Nervous System, Child, Child, Preschool, Developmental Disabilities, Female, HEK293 Cells, Humans, Intellectual Disability, Male, Mutation, Missense, RNA, RNA Helicases}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2017.09.014}, author = {Lessel, Davor and Schob, Claudia and K{\"u}ry, S{\'e}bastien and Reijnders, Margot R F and Harel, Tamar and Eldomery, Mohammad K and Coban-Akdemir, Zeynep and Denecke, Jonas and Edvardson, Shimon and Colin, Estelle and Stegmann, Alexander P A and Gerkes, Erica H and Tessarech, Marine and Bonneau, Dominique and Barth, Magalie and Besnard, Thomas and Cogn{\'e}, Benjamin and Revah-Politi, Anya and Strom, Tim M and Rosenfeld, Jill A and Yang, Yaping and Posey, Jennifer E and Immken, LaDonna and Oundjian, Nelly and Helbig, Katherine L and Meeks, Naomi and Zegar, Kelsey and Morton, Jenny and Schieving, Jolanda H and Claasen, Ana and Huentelman, Matthew and Narayanan, Vinodh and Ramsey, Keri and Brunner, Han G and Elpeleg, Orly and Mercier, Sandra and B{\'e}zieau, St{\'e}phane and Kubisch, Christian and Kleefstra, Tjitske and Kindler, Stefan and Lupski, James R and Kreienkamp, Hans-J{\"u}rgen} } @article {75, title = {Monoallelic and Biallelic Variants in EMC1 Identified in Individuals with Global Developmental Delay, Hypotonia, Scoliosis, and Cerebellar Atrophy.}, journal = {Am J Hum Genet}, volume = {98}, year = {2016}, month = {2016 Mar 03}, pages = {562-570}, abstract = {

The paradigm of a single gene associated with one specific phenotype and mode of inheritance has been repeatedly challenged. Genotype-phenotype correlations can often be traced to different mutation types, localization of the variants in distinct protein domains, or the trigger of or escape from nonsense-mediated decay. Using whole-exome sequencing, we identified homozygous variants in EMC1 that segregated with a phenotype of developmental delay, hypotonia, scoliosis, and cerebellar atrophy in three families. In addition, a de novo heterozygous EMC1 variant was seen in an individual with a similar clinical and MRI imaging phenotype. EMC1 encodes a member of the endoplasmic reticulum (ER)-membrane protein complex (EMC), an evolutionarily conserved complex that has been proposed to have multiple roles in ER-associated degradation, ER-mitochondria tethering, and proper assembly of multi-pass transmembrane proteins. Perturbations of protein folding and organelle crosstalk have been implicated in neurodegenerative processes including cerebellar atrophy. We propose EMC1 as a gene in which either biallelic or monoallelic variants might lead to a syndrome including intellectual disability and preferential degeneration of the cerebellum.

}, keywords = {Adolescent, Alleles, Amino Acid Sequence, Atrophy, Cerebellum, Child, Child, Preschool, Developmental Disabilities, Endoplasmic Reticulum-Associated Degradation, Female, Genetic Association Studies, Genetic Variation, Heterozygote, Humans, Magnetic Resonance Imaging, Male, Molecular Sequence Data, Muscle Hypotonia, Mutation, Pedigree, Protein Folding, Proteins, Scoliosis}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.01.011}, author = {Harel, Tamar and Yesil, G{\"o}zde and Bayram, Yavuz and Coban-Akdemir, Zeynep and Charng, Wu-Lin and Karaca, Ender and Al Asmari, Ali and Eldomery, Mohammad K and Hunter, Jill V and Jhangiani, Shalini N and Rosenfeld, Jill A and Pehlivan, Davut and El-Hattab, Ayman W and Saleh, Mohammed A and LeDuc, Charles A and Muzny, Donna and Boerwinkle, Eric and Gibbs, Richard A and Chung, Wendy K and Yang, Yaping and Belmont, John W and Lupski, James R} } @article {41, title = {Nonrecurrent PMP22-RAI1 contiguous gene deletions arise from replication-based mechanisms and result in Smith-Magenis syndrome with evident peripheral neuropathy.}, journal = {Hum Genet}, volume = {135}, year = {2016}, month = {2016 Oct}, pages = {1161-74}, abstract = {

Hereditary neuropathy with liability to pressure palsies (HNPP) and Smith-Magenis syndrome (SMS) are genomic disorders associated with deletion copy number variants involving chromosome 17p12 and 17p11.2, respectively. Nonallelic homologous recombination (NAHR)-mediated recurrent deletions are responsible for the majority of HNPP and SMS cases; the rearrangement products encompass the key dosage-sensitive genes PMP22 and RAI1, respectively, and result in haploinsufficiency for these genes. Less frequently, nonrecurrent genomic rearrangements occur at this locus. Contiguous gene duplications encompassing both PMP22 and RAI1, i.e., PMP22-RAI1 duplications, have been investigated, and replication-based mechanisms rather than NAHR have been proposed for these rearrangements. In the current study, we report molecular and clinical characterizations of six subjects with the reciprocal phenomenon of deletions spanning both genes, i.e., PMP22-RAI1 deletions. Molecular studies utilizing high-resolution array comparative genomic hybridization and breakpoint junction sequencing identified mutational signatures that were suggestive of replication-based mechanisms. Systematic clinical studies revealed features consistent with SMS, including features of intellectual disability, speech and gross motor delays, behavioral problems and ocular abnormalities. Five out of six subjects presented clinical signs and/or objective electrophysiologic studies of peripheral neuropathy. Clinical profiling may improve the clinical management of this unique group of subjects, as the peripheral neuropathy can be more severe or of earlier onset as compared to SMS patients having the common recurrent deletion. Moreover, the current study, in combination with the previous report of PMP22-RAI1 duplications, contributes to the understanding of rare complex phenotypes involving multiple dosage-sensitive genes from a genetic mechanistic standpoint.

}, keywords = {Adolescent, Adult, Child, Child, Preschool, Chromosomes, Human, Pair 17, DNA Copy Number Variations, DNA Replication, Female, Gene Deletion, Haploinsufficiency, Homologous Recombination, Humans, Intellectual Disability, Male, Mutation, Myelin Proteins, Smith-Magenis Syndrome, Trans-Activators, Transcription Factors}, issn = {1432-1203}, doi = {10.1007/s00439-016-1703-5}, author = {Yuan, Bo and Neira, Juanita and Gu, Shen and Harel, Tamar and Liu, Pengfei and Brice{\~n}o, Ignacio and Elsea, Sarah H and G{\'o}mez, Alberto and Potocki, Lorraine and Lupski, James R} } @article {97, title = {POGZ truncating alleles cause syndromic intellectual disability.}, journal = {Genome Med}, volume = {8}, year = {2016}, month = {2016 Jan 06}, pages = {3}, abstract = {

BACKGROUND: Large-scale cohort-based whole exome sequencing of individuals with neurodevelopmental disorders (NDDs) has identified numerous novel candidate disease genes; however, detailed phenotypic information is often lacking in such studies. De novo mutations in pogo transposable element with zinc finger domain (POGZ) have been identified in six independent and diverse cohorts of individuals with NDDs ranging from autism spectrum disorder to developmental delay.

METHODS: Whole exome sequencing was performed on five unrelated individuals. Sanger sequencing was used to validate variants and segregate mutations with the phenotype in available family members.

RESULTS: We identified heterozygous truncating mutations in POGZ in five unrelated individuals, which were confirmed to be de novo or not present in available parental samples. Careful review of the phenotypes revealed shared features that included developmental delay, intellectual disability, hypotonia, behavioral abnormalities, and similar facial characteristics. Variable features included short stature, microcephaly, strabismus and hearing loss.

CONCLUSIONS: While POGZ has been associated with neurodevelopmental disorders in large cohort studies, our data suggest that loss of function variants in POGZ lead to an identifiable syndrome of NDD with specific phenotypic traits. This study exemplifies the era of human reverse clinical genomics ushered in by large disease-directed cohort studies; first defining a new syndrome molecularly and, only subsequently, phenotypically.

}, keywords = {Adolescent, Adult, Alleles, Child, Preschool, Exome, Female, Heterozygote, Humans, Infant, Intellectual Disability, Male, Mutation, Sequence Analysis, DNA, Transposases}, issn = {1756-994X}, doi = {10.1186/s13073-015-0253-0}, author = {White, Janson and Beck, Christine R and Harel, Tamar and Posey, Jennifer E and Jhangiani, Shalini N and Tang, Sha and Farwell, Kelly D and Powis, Z{\"o}e and Mendelsohn, Nancy J and Baker, Janice A and Pollack, Lynda and Mason, Kati J and Wierenga, Klaas J and Arrington, Daniel K and Hall, Melissa and Psychogios, Apostolos and Fairbrother, Laura and Walkiewicz, Magdalena and Person, Richard E and Niu, Zhiyv and Zhang, Jing and Rosenfeld, Jill A and Muzny, Donna M and Eng, Christine and Beaudet, Arthur L and Lupski, James R and Boerwinkle, Eric and Gibbs, Richard A and Yang, Yaping and Xia, Fan and Sutton, V Reid} }