Sali M K Farhan1, John F Robinson2, Adam D McIntyre2, Maria G Marrosu3, Anna F Ticca3, Sara Loddo4, Nicola Carboni5, Francesco Brancati6, Robert A Hegele7. 1. Departments of Medicine and Biochemistry, Western University, London, Ontario, Canada; Robarts Research, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada. 2. Robarts Research, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada. 3. Department of Public Health, Clinical and Molecular Medicine, University of Cagliari, Cagliari, Italy. 4. IRCCS Casa Sollievo della Sofferenza, Istituto Mendel, San Giovanni Rotondo, Italy. 5. Division of Neurology, Hospital San Francesco of Nuoro, Nuoro, Italy. 6. Department of Medical, Oral and Biotechnological Sciences, Gabriele D'Annunzio University of Chieti-Pescara, Italy. 7. Departments of Medicine and Biochemistry, Western University, London, Ontario, Canada; Robarts Research, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada. Electronic address: hegele@robarts.ca.
Abstract
BACKGROUND: Familial lipodystrophies are rare inherited disorders associated with redistribution of body fat and development of dyslipidemia, insulin resistance, and diabetes. We previously reported 2 siblings with unusual late-onset familial partial lipodystrophy in whom heretofore known causative genes had been excluded. We hypothesized they had a mutation in a novel lipodystrophy gene. METHODS: Our approach centred on whole exome sequencing of the patients' DNA, together with genetic linkage analysis and a bioinformatic prioritization analysis. All candidate variants were assessed in silico and available family members were genotyped to assess segregation of mutations. RESULTS: Our prioritization algorithm led us to a novel homozygous nonsense variant, namely p.Ala507fsTer563 in the hormone sensitive lipase gene encoding, an enzyme that is differentially expressed in adipocytes and steroidogenic tissues. Pathogenicity of the mutation was supported in bioinformatic analyses and variant cosegregation within the family. CONCLUSIONS: We have identified a novel nonsense mutation in hormone sensitive lipase gene, which likely explains the lipodystrophy phenotype observed in these patients.
BACKGROUND:Familial lipodystrophies are rare inherited disorders associated with redistribution of body fat and development of dyslipidemia, insulin resistance, and diabetes. We previously reported 2 siblings with unusual late-onset familial partial lipodystrophy in whom heretofore known causative genes had been excluded. We hypothesized they had a mutation in a novel lipodystrophy gene. METHODS: Our approach centred on whole exome sequencing of the patients' DNA, together with genetic linkage analysis and a bioinformatic prioritization analysis. All candidate variants were assessed in silico and available family members were genotyped to assess segregation of mutations. RESULTS: Our prioritization algorithm led us to a novel homozygous nonsense variant, namely p.Ala507fsTer563 in the hormone sensitive lipase gene encoding, an enzyme that is differentially expressed in adipocytes and steroidogenic tissues. Pathogenicity of the mutation was supported in bioinformatic analyses and variant cosegregation within the family. CONCLUSIONS: We have identified a novel nonsense mutation in hormone sensitive lipase gene, which likely explains the lipodystrophy phenotype observed in these patients.
Authors: Nevin Ajluni; Rasimcan Meral; Adam H Neidert; Graham F Brady; Eric Buras; Barbara McKenna; Frank DiPaola; Thomas L Chenevert; Jeffrey F Horowitz; Colleen Buggs-Saxton; Amit R Rupani; Peedikayil E Thomas; Marwan K Tayeh; Jeffrey W Innis; M Bishr Omary; Hari Conjeevaram; Elif A Oral Journal: Clin Endocrinol (Oxf) Date: 2017-03-27 Impact factor: 3.478