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Recurrent nonsense mutations within the type VII collagen gene in patients with severe recessive dystrophic epidermolysis bullosa

Journal Article · · American Journal of Human Genetics; (United States)
OSTI ID:6811123
; ;  [1]; ;  [2]; ;  [3]
  1. Hopital Henri Mondor, Creteil (France)
  2. Hopital Necker-Enfants Malades, Paris (France)
  3. Thomas Jefferson Univ., Philadelphia, PA (United States)
The generalized mutilating form of recessive dystrophic epidermolysis bullosa (i.e., the Hallopeau-Siemens type; HS-RDEB) is a life-threatening disease characterized by extreme mucocutaneous fragility associated with absent or markedly altered anchoring fibrils (AF). Recently, the authors reported linkage between HS-RDEB and the type VII collagen gene (COL7A1), which encodes the major component of AF. In this study, they investigated 52 unrelated HS-RDEB patients and 2 patients with RDEB inversa for the presence, at CpG dinucleotides, of mutations changing CGA arginine codons to premature stop codons TGA within the COL7A1 gene. Eight exons containing 10 CGA codons located in the amino-terminal domain of the COL7A1 gene were studied. Mutation analysis was performed using denaturing gradient gel electrophoresis of PCR-amplified genomic fragments. Direct sequencing of PCR-amplified products with altered electrophoretic mobility led to the characterization of three premature stop codons, each in a single COL7A1 allele, in four patients. Two patients (one affected with HS-RDEB and the other with RDEB inversa) have the same C-to-T transition at arginine codon 109. Two other HS-RDEB patients have a C-to-T transition at arginine 1213 and 1216, respectively. These nonsense mutations predict the truncation of [approximately]56%-92% of the polypeptide, including the collagenous and the noncollagenous NC-2 domains. On the basis of linkage analysis, which showed no evidence for locus heterogeneity in RDEB, it is expected that these patients are compound heterozygotes and have additional mutations on the other COL7A1 allele, leading to impaired AF formation. These results indicate that stop mutations within the COL7A1 gene can underlie both HS-RDEB and RDEB inversa, thus providing further evidence for the implication of this gene in RDEB. 46 refs., 3 figs., 1 tab.
OSTI ID:
6811123
Journal Information:
American Journal of Human Genetics; (United States), Journal Name: American Journal of Human Genetics; (United States) Vol. 55:2; ISSN AJHGAG; ISSN 0002-9297
Country of Publication:
United States
Language:
English