title: Detection of SQSTM1/P392L post-zygotic mutations in Paget's disease of bone.
abstract: Paget's disease of bone (PDB) is transmitted, in one-third of cases, in an autosomal dominant mode of inheritance with incomplete penetrance. The SQSTM1/P392L germinal mutation is the most common mutation associated with PDB. Given the focal nature of PDB, one team of investigators showed that SQSTM1/P392L somatic mutations could occur in pagetic bone lesions in the absence of germinal mutations detectable in the peripheral blood. The objectives of this study were to develop a reliable method to detect SQSTM1/P392L post-zygotic mutations, by optimizing a polymerase chain reaction (PCR)-clamping method reported to be effective in detecting post-zygotic mutations in peripheral blood from patients with fibrous dysplasia; and to evaluate the frequency of this post-zygotic mutation in PDB patients. We used a locked nucleic acid (LNA) specifically designed for the SQSTM1/P392L mutation, which blocks the wild-type allele amplification during the PCR. DNA from 376 pagetic patients and 297 controls, all without any SQSTM1/P392L germinal mutation, was analyzed. We found that 4.8 % of PDB patients and 1.4 % of controls were carriers of this post-zygotic mutation [p = 0.013, OR 3.68 (1.23; 11.00)]. PDB patient carriers of a post-zygotic mutation had a lower number of affected bones and Renier's index than patients carrying a germinal mutation, suggesting a lower disease extension. We also demonstrated that this post-zygotic mutation was restricted to the monocytic lineage. These results confirmed that LNA PCR clamping is effective for the detection of SQSTM1/P392L post-zygotic mutations, which may occur in patients with PDB.
authors.affiliation: CHU de Québec Research Centre, Rhumatologie-R4774, CHU de Québec, 2705 boulevard Laurier, Québec, QC, G1V 4G2, Canada.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Guay-Bélanger
authors.forename: Sylvain
authors.initials: S
authors.lastname: Picard
authors.forename: Edith
authors.initials: E
authors.lastname: Gagnon
authors.forename: Jean
authors.initials: J
authors.lastname: Morissette
authors.forename: Ethel S
authors.initials: ES
authors.lastname: Siris
authors.forename: Philippe
authors.initials: P
authors.lastname: Orcel
authors.forename: Jacques P
authors.initials: JP
authors.lastname: Brown
authors.forename: Laëtitia
authors.initials: L
authors.lastname: Michou
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D004252:DNA Mutational Analysis; D005260:Female; D005500:Follow-Up Studies; D056726:Genetic Association Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D010001:Osteitis Deformans / Q000235:genetics* / Q000473:pathology; D016133:Polymerase Chain Reaction / Q000379:methods; D011379:Prognosis; D000071456:Sequestosome-1 Protein; D055815:Young Adult; D015053:Zygote
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C099718:SQSTM1 protein, human; D000071456:Sequestosome-1 Protein