@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 {194, title = {De novo mutations in NALCN cause a syndrome characterized by congenital contractures of the limbs and face, hypotonia, and developmental delay.}, journal = {Am J Hum Genet}, volume = {96}, year = {2015}, month = {2015 Mar 05}, pages = {462-73}, abstract = {

Freeman-Sheldon syndrome, or distal arthrogryposis type 2A (DA2A), is an autosomal-dominant condition caused by mutations in MYH3 and characterized by multiple congenital contractures of the face and limbs and normal cognitive development. We identified a subset of five individuals who had been putatively diagnosed with "DA2A with severe neurological abnormalities" and for whom congenital contractures of the limbs and face, hypotonia, and global developmental delay had resulted in early death in three cases; this is a unique condition that we now refer to as CLIFAHDD syndrome. Exome sequencing identified missense mutations in the sodium leak channel, non-selective (NALCN) in four families affected by CLIFAHDD syndrome. We used molecular-inversion probes to screen for NALCN in a cohort of 202 distal arthrogryposis (DA)-affected individuals as well as concurrent exome sequencing of six other DA-affected individuals, thus revealing NALCN mutations in ten additional families with "atypical" forms of DA. All 14 mutations were missense variants predicted to alter amino acid residues in or near the S5 and S6 pore-forming segments of NALCN, highlighting the functional importance of these segments. In vitro functional studies demonstrated that NALCN alterations nearly abolished the expression of wild-type NALCN, suggesting that alterations that cause CLIFAHDD syndrome have a dominant-negative effect. In contrast, homozygosity for mutations in other regions of NALCN has been reported in three families affected by an autosomal-recessive condition characterized mainly by hypotonia and severe intellectual disability. Accordingly, mutations in NALCN can cause either a recessive or dominant condition characterized by varied though overlapping phenotypic features, perhaps based on the type of mutation and affected protein domain(s).

}, keywords = {Arthrogryposis, Contracture, Craniofacial Dysostosis, Cytoskeletal Proteins, Exome, Extremities, Face, Female, Gene Frequency, High-Throughput Nucleotide Sequencing, Homozygote, Humans, Infant, Male, Muscle Hypotonia, Mutation, Missense, Sodium Channels}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2015.01.003}, author = {Chong, Jessica X and McMillin, Margaret J and Shively, Kathryn M and Beck, Anita E and Marvin, Colby T and Armenteros, Jose R and Buckingham, Kati J and Nkinsi, Naomi T and Boyle, Evan A and Berry, Margaret N and Bocian, Maureen and Foulds, Nicola and Uzielli, Maria Luisa Giovannucci and Haldeman-Englert, Chad and Hennekam, Raoul C M and Kaplan, Paige and Kline, Antonie D and Mercer, Catherine L and Nowaczyk, Malgorzata J M and Klein Wassink-Ruiter, Jolien S and McPherson, Elizabeth W and Moreno, Regina A and Scheuerle, Angela E and Shashi, Vandana and Stevens, Cathy A and Carey, John C and Monteil, Arnaud and Lory, Philippe and Tabor, Holly K and Smith, Joshua D and Shendure, Jay and Nickerson, Deborah A and Bamshad, Michael J} } @article {256, title = {Mutations in PIEZO2 cause Gordon syndrome, Marden-Walker syndrome, and distal arthrogryposis type 5.}, journal = {Am J Hum Genet}, volume = {94}, year = {2014}, month = {2014 May 01}, pages = {734-44}, abstract = {

Gordon syndrome (GS), or distal arthrogryposis type 3, is a rare, autosomal-dominant disorder characterized by cleft palate and congenital contractures of the hands and feet. Exome sequencing of five GS-affected families identified mutations in piezo-type mechanosensitive ion channel component 2 (PIEZO2) in each family. Sanger sequencing revealed PIEZO2 mutations in five of seven additional families studied (for a total of 10/12 [83\%] individuals), and nine families had an identical c.8057G>A (p.Arg2686His) mutation. The phenotype of GS overlaps with distal arthrogryposis type 5 (DA5) and Marden-Walker syndrome (MWS). Using molecular inversion probes for targeted sequencing to screen PIEZO2, we found mutations in 24/29 (82\%) DA5-affected families and one of two MWS-affected families. The presence of cleft palate was significantly associated with c.8057G>A (Fisher{\textquoteright}s exact test, adjusted p value < 0.0001). Collectively, although GS, DA5, and MWS have traditionally been considered separate disorders, our findings indicate that they are etiologically related and perhaps represent variable expressivity of the same condition.

}, keywords = {Abnormalities, Multiple, Arachnodactyly, Arthrogryposis, Blepharophimosis, Child, Child, Preschool, Cleft Palate, Clubfoot, Connective Tissue Diseases, Contracture, Exome, Female, Hand Deformities, Congenital, Humans, Ion Channels, Male, Mutation, Ophthalmoplegia, Pedigree, Retinal Diseases}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2014.03.015}, author = {McMillin, Margaret J and Beck, Anita E and Chong, Jessica X and Shively, Kathryn M and Buckingham, Kati J and Gildersleeve, Heidi I S and Aracena, Mariana I and Aylsworth, Arthur S and Bitoun, Pierre and Carey, John C and Clericuzio, Carol L and Crow, Yanick J and Curry, Cynthia J and Devriendt, Koenraad and Everman, David B and Fryer, Alan and Gibson, Kate and Giovannucci Uzielli, Maria Luisa and Graham, John M and Hall, Judith G and Hecht, Jacqueline T and Heidenreich, Randall A and Hurst, Jane A and Irani, Sarosh and Krapels, Ingrid P C and Leroy, Jules G and Mowat, David and Plant, Gordon T and Robertson, Stephen P and Schorry, Elizabeth K and Scott, Richard H and Seaver, Laurie H and Sherr, Elliott and Splitt, Miranda and Stewart, Helen and Stumpel, Constance and Temel, Sehime G and Weaver, David D and Whiteford, Margo and Williams, Marc S and Tabor, Holly K and Smith, Joshua D and Shendure, Jay and Nickerson, Deborah A and Bamshad, Michael J} } @article {269, title = {Sclerocornea in a patient with van den Ende-Gupta syndrome homozygous for a SCARF2 microdeletion.}, journal = {Am J Med Genet A}, volume = {164A}, year = {2014}, month = {2014 May}, pages = {1170-4}, abstract = {

Van den Ende-Gupta Syndrome (VDEGS) is an autosomal recessive disorder characterized by blepharophimosis, distinctive nose, hypoplastic maxilla, and skeletal abnormalities. Using homozygosity mapping in four VDEGS patients from three consanguineous families, Anastacio et al. [Anastacio et al. (2010); Am J Hum Genet 87:553-559] identified homozygous mutations in SCARF2, located at 22q11.2. Bedeschi et al. [2010] described a VDEGS patient with sclerocornea and cataracts with compound heterozygosity for the common 22q11.2 microdeletion and a hemizygous SCARF2 mutation. Because sclerocornea had been described in DiGeorge-velo-cardio-facial syndrome but not in VDEGS, they suggested that the ocular abnormalities were caused by the 22q11.2 microdeletion. We report on a 23-year-old male who presented with bilateral sclerocornea and the VDGEGS phenotype who was subsequently found to be homozygous for a 17 bp deletion in exon 4 of SCARF2. The occurrence of bilateral sclerocornea in our patient together with that of Bedeschi et al., suggests that the full VDEGS phenotype may include sclerocornea resulting from homozygosity or compound heterozygosity for loss of function variants in SCARF2.

}, keywords = {Abnormalities, Multiple, Adult, Arachnodactyly, Blepharophimosis, Bone and Bones, Chromosomes, Human, Pair 22, Contracture, Cornea, Corneal Diseases, Exons, Facies, Hand Deformities, Congenital, Homozygote, Humans, Male, Phenotype, Radiography, Scavenger Receptors, Class F, Sequence Analysis, DNA, Sequence Deletion, Young Adult}, issn = {1552-4833}, doi = {10.1002/ajmg.a.36425}, author = {Migliavacca, Michele P and Sobreira, Nara L M and Antonialli, Graziela P M and Oliveira, Mariana M and Melaragno, Maria Isabel S A and Casteels, Ingele and de Ravel, Thomy and Brunoni, Decio and Valle, David and Perez, Ana Beatriz A} }