Keratitis-Ichthyosis-Deafness Syndrome Caused by Missense Mutation in GJB2 Encoding Connexin 26 in a Chinese Patient

The case report discusses a 36-year-old Chinese man diagnosed with Keratitis-ichthyosis-deafness (KID) syndrome, a rare congenital disorder caused by a heterozygous missense mutation in GJB2 or GJB6 genes. The patient presented with scalp alopecia, absence of eyelashes, pubic hair, and axillary hair, along with other symptoms. Genetic testing revealed a nucleotide change, c.40A > T, in exon 2 of GJB2, resulting in the substitution of asparagine for tyrosine at position 14 (N14Y) in the N-terminal domain of connexin 26. This mutation has not been previously reported in domestic literature. The patient's treatment included oral retinoic acid, antibiotics, and topical moisturizer packs. The findings expand the mutation spectrum of KID syndrome in the Chinese population and provide a new understanding of the genotype–phenotype correlation.