关键词: 表皮松解, 大疱性, 营养不良性, DNA突变分析, COL7A1基因, 错义突变

Abstract: 【Abstract】 Objective To detect gene mutations in a pedigree with dominant dystrophic epidermolysis bullosa （DDEB）. Methods A 20-year-old male proband presented with repeated blisters, ulceration, pigmentation, scars on the limbs, and deformation of the nails/toenails after birth. There were 5 patients in the 3-generation family, and they all presented with typical skin lesions. Peripheral blood samples were obtained from 14 members of the pedigree （including the 5 patients） and 100 unrelated healthy controls. Whole-exon sequencing was performed on the proband to identify relevant mutation sites, which were then confirmed in the family by Sanger sequencing. Results Genetic testing indicated that the proband and the other 4 patients all carried a missense mutation （c.7885G>A） in exon 107 of the COL7A1 gene, resulting in the substitution of glycine by arginine at amino acid position 2629 （p.G2629R）. The mutation was not identified in the 9 healthy relatives or 100 unrelated healthy controls. The mutation co-segregated with DDEB in the family, and was not included in databases such as Pubmed, HGMD or ClinVar, suggesting it was a novel missense mutation. The amino acid encoded by this mutation may alter the structure of type Ⅶ collagen, thereby affecting its function. Conclusion A novel missense mutation was identified in exon 107 of the COL7A1 gene in the family with DDEB, expanding the spectrum of mutations in the COL7A1 gene.

Key words: Epidermolysis bullosa dystrophica, DNA mutational analysis, COL7A1 gene, Missense mutation