Abstract: 【Abstract】 Objective To analyze clinical and genetic characteristics of a family with familial generalized lentiginosis, and to identify the causative gene mutation. Methods Clinical characteristics and inherited pattern were analyzed in a family with familial generalized lentiginosis. Peripheral blood samples were obtained from the proband, his affected father and healthy mother, and genomic DNA was extracted. PCR was performed to amplify all exons and their flanking sequences of the SASH1 gene, followed by DNA sequencing. The proband′s mother and 100 unrelated healthy controls served as controls to determine the mutation site. Previous literature and gene mutation databases were searched to rule out the possibility that the SASH1 gene mutations were single nucleotide polymorphisms, and to determine whether it was a known mutation. Results A 4-generation family consisting of 17 members was investigated, and there were 9 patients in the family, including 7 males and 2 females. Patients existed in each generation, and the disease was inherited in an autosomal dominant manner in this family. Gene sequencing revealed a heterozygous duplication mutation c.49_54dupCCCGAG in exon 1 of the SASH1 gene in the proband and his father. This mutation was not found in his mother or healthy controls, and had not been reported in previous literature or gene mutation databases. Conclusion The heterozygous duplication mutation c.49_54dupCCCGAG in the SASH1 gene is a pathogenic mutation for the clinical manifestations of familial generalized lentiginosis in this family.

Key words: Lentigo, DNA mutational analysis, Familial generalized lentiginosis, Gene, SASH1, Duplication mutation