Premium
Identification of the molecular defect in patients with peroxisomal mosaicism using a novel method involving culturing of cells at 40°C: Implications for other inborn errors of metabolism
Author(s) -
Gootjes Jeannette,
Schmohl Frank,
Mooijer Petra A.W.,
Dekker Conny,
Mandel Hanna,
Topcu Meral,
Huemer Martina,
von Schütz M.,
Marquardt Thorsten,
Smeitink Jan A.,
Waterham Hans R.,
Wanders Ronald J.A.
Publication year - 2004
Publication title -
human mutation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 162
eISSN - 1098-1004
pISSN - 1059-7794
DOI - 10.1002/humu.20062
Subject(s) - zellweger syndrome , peroxisome , complementation , biology , peroxisomal disorder , biogenesis , adrenoleukodystrophy , mutation , genetics , gene , microbiology and biotechnology , phenotype
Abstract The peroxisome biogenesis disorders (PBDs), which comprise Zellweger syndrome (ZS), neonatal adrenoleukodystrophy, and infantile Refsum disease (IRD), represent a spectrum of disease severity, with ZS being the most severe, and IRD the least severe disorder. The PBDs are caused by mutations in one of the at least 12 different PEX genes encoding proteins involved in the biogenesis of peroxisomes. We report the biochemical characteristics and molecular basis of a subset of atypical PBD patients. These patients were characterized by abnormal peroxisomal plasma metabolites, but otherwise normal to very mildly abnormal peroxisomal parameters in cultured skin fibroblasts, including a mosaic catalase immunofluorescence pattern in fibroblasts. Since this latter feature made standard complementation analysis impossible, we developed a novel complementation technique in which fibroblasts were cultured at 40°C, which exacerbates the defect in peroxisome biogenesis. Using this method, we were able to assign eight patients to complementation group 3 (CG3), followed by the identification of a single homozygous c.959C>T (p.S320F) mutation in their PEX12 gene. We also investigated various peroxisomal biochemical parameters in fibroblasts at 30°C, 37°C, and 40°C, and found that all parameters showed a temperature‐dependent behavior. The principle of culturing cells at elevated temperatures to exacerbate the defect in peroxisome biogenesis, and thereby preventing certain mutations from being missed, may well have a much wider applicability for a range of different inborn errors of metabolism. Hum Mutat 24:130–139, 2004. © 2004 Wiley‐Liss, Inc.