Abstract： Objective To analyse the mutation of K17 gene in a pedigree with steatocystoma multi-plex. Methods Blood samples were obtained from 3 affected and 3 normal individuals in a family with steatocystoma multiplex, as well as from 50 unrelated healthy individuals. Mutation scanning was carried out by PCR and direct sequencing. Results A heterozygous nucleotide transition (C→T) at position 428 in exon 1 of KI7 gene, which leads to the substitution of CGC (arginine) by TGC (histidine) at codon 94, was detected in the affected individuals, but not in normal family members or the 50 unrelated individuals. Conclusion A missense mutation (428C→T) in KI7 gene has been detected in affected individuals of this family, which seems to be a molecular basis of pathogenesis of steatocystoma multiplex.