De novo mutation of the connexin 26 gene associated with dominant non-syndromic sensorineural hearing loss

Mutations of the connexin 26 (Cx26) gene cause isolated recessive or domina nt hearing loss or both sensorineural hearing impairment and keratoderma. W e have identified the first de novo mutation of the Cx26 gene, R75 W, in a sporadic case of isolated profound hearing loss. R75 W has been previously observed in association with hearing impairment and keratoderma in one: fam ily and is thus thought to cause both syndromic and non-syndromic hearing l oss. This case illustrates the risk of a possible erroneous diagnosis of au tosomal recessive hearing loss in a sporadic case.