A case of keratitis-ichthyosis-deafness syndrome complicated by cutaneous squamous cell carcinoma: mutation analysis of the GJB2 gene and literature review

Abstract

Objective To analyze mutations in the GJB2 gene in a Chinese patient with keratitis-ichthyosis-deafness (KID) syndrome complicated by cutaneous squamous cell carcinoma. Methods Clinical data were collected from a patient with KID syndrome complicated by cutaneous squamous cell carcinoma. Peripheral blood samples were obtained from the patient and her parents, and DNA was extracted from these blood samples. PCR was performed to amplify the exon 2 of the GJB2 gene followed by direct DNA sequencing. Results A mutation (c.148G > A) was identified at position 148 in exon 2 of the GJB2 gene, which caused a codon change from GAC to AAC and resulted in the substitution of aspartate by asparagine at position 50 in the connexin26 (Cx26) protein (p.Asp50Asn). In addition, another mutation (c.79G > A) , which led to the substitution of valine by isoleucine at codon 27 in Cx26 (p.Val27Ile) , was found at position 79 in exon 2 of the GJB2 gene. Neither of the two mutations was detected in the patient's parents. Literature review revealed that 13 cases of KID syndrome complicated by cutaneous squamous cell carcinoma had been reported in abroad, and the mutation c.148G > A was detected in the GJB2 gene in all the 7 cases finally diagnosed by gene sequencing. Conclusion GJB2 gene mutations may be responsible for the clinical phenotype of KID syndrome in this Chinese patient, and the mutation c.148G > A may be related to the development of cutaneous squamous cell carcinoma. Key words: Mutation; Carcinoma, squamous cell; GJB2 gene; Keratitis-ichthyosis-deafness syndrome