Connexin 26 (GJB2) Mutations in Keratitis–Ichthyosis–Deafness Syndrome Presenting with Squamous Cell Carcinoma

The document reported a case of a 58-year-old Japanese woman with keratitis–ichthyosis–deafness (KID) syndrome, who developed squamous cell carcinoma (SCC) on her scalp and breast cancer. Genetic analysis revealed three heterozygous missense mutations in the connexin-26 (CX26) gene, with the D50N mutation being well-characterized in KID syndrome. The study suggested that CX26 dysfunction might predispose epidermal keratinocytes to neoplastic transformation, potentially leading to SCC. The presence of breast cancer in the patient also indicated a possible link between CX26 mutations and tumorigenesis in both cutaneous and non-cutaneous malignancies. The findings highlighted the need for long-term follow-up in KID syndrome patients due to the potential risk of malignancies.