Browsing by Subject "Exome"

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    Exome sequencing identifies novel dysferlin mutation in a family with pauci-symptomatic heterozygous carriers
    (BioMed Central, 2018-06-07) Jalali-Sefid-Dashti, Mahjoubeh; Nel, Melissa; Heckmann, Jeannine M; Gamieldien, Junaid
    Background We investigated a South African family of admixed ancestry in which the first generation (G1) developed insidious progressive distal to proximal weakness in their twenties, while their offspring (G2) experienced severe unexpected symptoms of myalgia and cramps since adolescence. Our aim was to identify deleterious mutations that segregate with the affected individuals in this family. Methods Exome sequencing was performed on five cases, which included three affected G1 siblings and two pauci-symptomatic G2 offspring. As controls we included an unaffected G1 sibling and a spouse of one of the G1 affected individuals. Homozygous or potentially compound heterozygous variants that were predicted to be functional and segregated with the affected G1 siblings, were further evaluated. Additionally, we considered variants in all genes segregating exclusively with the affected (G1) and pauci-symptomatic (G2) individuals to address the possibility of a pseudo-autosomal dominant inheritance pattern in this family. Results All affected G1 individuals were homozygous for a novel truncating p.Tyr1433Ter DYSF (dysferlin) mutation, with their asymptomatic sibling and both pauci-symptomatic G2 offspring carrying only a single mutant allele. Sanger sequencing confirmed segregation of the variant. No additional potentially contributing variant was found in the DYSF or any other relevant gene in the pauci-symptomatic carriers. Conclusion Our finding of a truncating dysferlin mutation confirmed dysferlinopathy in this family and we propose that the single mutant allele is the primary contributor to the neuromuscular symptoms seen in the second-generation pauci-symptomatic carriers.
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    Expanding the clinical spectrum of hereditary fibrosing poikiloderma with tendon contractures, myopathy and pulmonary fibrosis due to FAM111B mutations
    (2015) Mercier, Sandra; Küry, Sébastien; Salort-Campana, Emmanuelle; Magot, Armelle; Agbim, Uchenna; Besnard, Thomas; Bodak, Nathalie; Bou-Hanna, Chantal; Bréhéret, Flora; Brunelle, Perrine; Caillon, Florence; Chabrol, Brigitte; Cormier-Daire, Valérie; David, Albert; Eymard, Bruno; Faivre, Laurence; Figarella-Branger, Dominique; Fleurence, Emmanuelle; Ganapathi, Mythily; Gherardi, Romain; Goldenberg, Alice; Hamel, Antoine; Igual, Jeanine; Irvine, Alan D; Israël-Biet, Dominique; Kannengiesser, Caroline; Laboisse, Christian; Le Caignec, Cédric; Mahé, Jean-Yves; Mallet, Stéphanie; MacGowan, Stuart; McAleer, Maeve A; McLean, Irwin; Méni, Cécile; Munnich, Arnold; Mussini, Jean-Marie; Nagy, Peter L; Odel, Jeffrey; O’Regan, Grainne M; Péréon, Yann; Perrier, Julie; Piard, Juliette; Puzenat, Eve; Sampson, Jacinda B; Smith, Frances; Soufir, Nadem; Tanji, Kurenai; Thauvin, Christel; Ulane, Christina; Watson, Rosemarie M; Khumalo, Nonhlanhla P; Mayosi, Bongani M; Barbarot, Sébastien; Bézieau, Stéphane
    BackgroundHereditary Fibrosing Poikiloderma (HFP) with tendon contractures, myopathy and pulmonary fibrosis (POIKTMP [MIM 615704]) is a very recently described entity of syndromic inherited poikiloderma. Previously by using whole exome sequencing in five families, we identified the causative gene, FAM111B (NM_198947.3), the function of which is still unknown. Our objective in this study was to better define the specific features of POIKTMP through a larger series of patients.MethodsClinical and molecular data of two families and eight independent sporadic cases, including six new cases, were collected.ResultsKey features consist of: (i) early-onset poikiloderma, hypotrichosis and hypohidrosis; (ii) multiple contractures, in particular triceps surae muscle contractures; (iii) diffuse progressive muscular weakness; (iv) pulmonary fibrosis in adulthood and (v) other features including exocrine pancreatic insufficiency, liver impairment and growth retardation. Muscle magnetic resonance imaging was informative and showed muscle atrophy and fatty infiltration. Histological examination of skeletal muscle revealed extensive fibroadipose tissue infiltration. Microscopy of the skin showed a scleroderma-like aspect with fibrosis and alterations of the elastic network. FAM111B gene analysis identified five different missense variants (two recurrent mutations were found respectively in three and four independent families). All the mutations were predicted to localize in the trypsin-like cysteine/serine peptidase domain of the protein. We suggest gain-of-function or dominant-negative mutations resulting in FAM111B enzymatic activity changes.ConclusionsHFP with tendon contractures, myopathy and pulmonary fibrosis, is a multisystemic disorder due to autosomal dominant FAM111B mutations. Future functional studies will help in understanding the specific pathological process of this fibrosing disorder.