Abstract: Objectives To identify the COL7A1 gene mutation in a recessive dystrophic epidermolysis bullosa (RDEB) family,and to perform prenatal diagnosis in the patient's offspring.Methods The genomic DNA,obtained from the patient and his wife,was used to screen all 118 exons of the type VII collagen gene (COL7A1) via polymerase chain reaction (PCR) followed by direct DNA sequencing of the PCR products.Fetal DNA was extracted from amniotic fluid of the patient's wife at the 15th week of gestation.PCR,direct DNA sequencing and restriction fragment length polymorphisms (RFLPs) were performed for prenatal diagnosis.Results The patient in this study was a compound heterozygote for a S48P missense mutation in exon 2 and an 11 base pair deletion (3625del11) leading to a premature termination codon (PTC) in exon 27,which are a novel combination of COL7A1 mutations in RDEB.The COL7A1 genotype of his wife was normal.In the fetus,the same deletion of 11 base pair (3625del11) was found in exon 27,but no mutation was found in exon 2.Thus,the fetus was predicted to be a clinically normal child with a carrier genotype.Seven months later,a clinically unaffected male infant was born and the prediction was confirmed.Conclusion We successfully performed the first DNA-based prenatal diagnosis in China in a family with Hallopeau-Siemens RDEB.

Key words: Epidermolysis bullosa dystrophica, Genes,recessive, Prenatal diagnosis