Mutation analysis of causative genes in a case of congenital hypotrichosis

Abstract

Objective To identify the genetic cause of a case of congenital hypotrichosis by a next-generation sequencing technology. Methods A 9-year and 3-month-old girl presented with few villous hairs at birth, which grew slowly. Skin examination showed sparse, thin, soft, woolly and light-yellow hairs, small amount of hairs on the top of the head and a less amount of hairs around the head, hairline recession and broadened forehead. No abnormality was found by ophthalmic examination. No similar aberrant phenotype was observed in the patient′s parents or her younger sister. Her parents were non-consanguineous marriage. Peripheral venous blood samples were obtained from the patient, her mother and younger sister. Genomic DNA was extracted and then analyzed by a next-generation sequencing technology. The suspected pathogenic mutations were validated by Sanger sequencing and subjected to bioinformatics analysis. Results Two mutations were identified in the CDH3 gene in the patient, including a c.1057G > T (p.D353Y) heterozygous mutation in exon 5 and a c.1767delC (p.I589Ifs) heterozygous mutation in exon 10. They were both novel mutations, and their pathogenicity was predicted by softwares. Sanger sequencing indicated that the c.1057G > T (p.D353Y) heterozygous mutation was inherited from the patient′s mother, and gene transfer analysis revealed that the c.1767delC (p.I589Ifs) heterozygous mutation was inherited from the patient′s father. Conclusion The c.1057G > T (p.D353Y) and c.1767delC (p.I589Ifs) heterozygous mutations may cause hypotrichosis and juvenile macular dystrophy in the patient, so careful observation and comprehensive ophthalmic examination should be performed on time for early diagnosis and treatment of eye symptoms. Key words: Hypotrichosis; Mutation; DNA mutational analysis; CDH3 gene