Mutations in connexin 26 (GJB2, Cx26) cause autosomal recessive and occasionally dominant non-syndromic sensorineural hearing loss (SNHL). Cx26 mutations have also been identified in SNHL with dermatological features of autosomal dominant diffuse palmoplantar hyperkeratosis (DPPK).^1–3

We describe a girl with bilateral sloping sensorineural hearing loss, striate palmoplantar hyperkeratosis (SPPK), and knuckle pads, who has a novel heterozygous missense mutation (G59R) in the connexin 26 gene (GJB2, Cx26). This mutation resides in the same codon in which a mutation was previously described for a family with dominant sensorineural hearing loss with a diffuse palmoplantar hyperkeratosis (DPPK).¹Cx26 mutations have not been reported previously with the striate form of palmoplantar hyperkeratosis nor with knuckle pads.

Mutations in Cx26 have also been described in a severe condition of congenital deafness, keratopachydermia, and constrictions of fingers and toes (Vohwinkel syndrome; OMIM 124500)^4,5 as well as in KID syndrome (OMIM 148210)⁴ with keratitis, icthyosis, and deafness.^6,7 To date, mutations in Cx26 have not been associated with a striate subtype of palmoplantar hyperkeratosis (SPPK) or with knuckle pads.

CASE REPORT

We report an 8 year old girl who had congenital onset of bilateral non-progressive SNHL, mild (30–40 dB) in the low frequencies (250–500 Hz), increasing to severe (75 dB) in the higher frequencies (⩾2000 Hz). At 6 years of age she developed striate linear lesions of keratoderma on the palms (fig 1A) and knuckle pads on the dorsum of fingers (fig 1B). Striate linear lesions on the soles and mild hyperkeratosis over one elbow were developing. She had mild hyperkeratotic lesions on the lateral aspect of her feet. She showed no evidence of restricting lesions or diffuse keratoderma. Teeth, hair, and nails were normal with no evidence of leuconychia. She was healthy with no risk factors for acquired …