Abstract: Objective To identify the gene mutations and mu tating patterns in a pedigree with X-linked anhidrotic ectodermal dysplasia(EDA)so as to provide a basis for gene diagnosis and genetic counselling of this disorder.Methods Polymerase chain reaction-singl strand conformation polymorphism(PCR-SSCP)analysis and DNA sequencing of amplified products were performed to screen mutations and mutating patterns of EDA1 gene,responsible for EDA pathogenesis,in a X-linked EDA family of Han people.Results Abnormal single strand bands were found in the amplified fra gments as well of exon 1 of EDA gene in the patients as well as their mothers,the carriers.The DNA sequencing of amplified products revealed a point mutation at nucleotide 404(C→Gtransversion)in the proband compared with that of the normal controls,which resulted in the transversion of histidine with glutamine at codon 54 in the ectodysplasin-A(H54Q).Meanwhile there were heterozyous double peaks of nucleotide Cand Gat the same position in his mother.Conclusion A missense mutation(404C→G)in exon 1 of EDA1gene has been determined in the pedigree with X-linked EDA,which is probably one of the molecular bases of EDA pathogenesis.

Key words: Ectodermal dysplasia, Mutation