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BackgroundKeratitis-Ichthyosis-Deafness (KID) syndrome is a rare condition characterized by pre-lingual sensorineural deafness with skin hyperkeratinization. The primary cause of the disease is a loss-of-function mutation in the GJB2 gene. Mutations in Argentinean patients have not been described.Case presentationWe studied a 2 year-old boy with bilateral congenital sensorineural deafness with dry skin over the entire body, hypotrichosis of the scalp, thin and light-blond hair. Analysis of the GJB2 gene nucleotide sequence revealed the substitution of guanine-148 by adenine predicted to result in an Asp50Asn amino acid substitution.ConclusionThis is the first KID report in a patient from Argentina. This de novo mutation proved to be the cause of keratitis-ichthyosis-deafness syndrome (KID-syndrome) in the patient, and has implications in medical genetic practice.

Mutations in the GJB2 gene are responsible for more than half of all cases of recessive non-syndromic deafness. This article presents a mutation analysis of the GJB2, GJB6, OTOF and MTRNR1 genes in 252 patients with sensorineural non-syndromic hearing loss. Thirty-one different mutations were identified in GJB2 and GJB6 in 86 of the 252 (34%) patients. We describe for the first time two new mutations in GJB2: the missense mutation c.29 T>C (p.Leu10Pro) in the N terminal domain and c.326 G>T (p.Gly109Val) in the intracytoplasmic domain of connexin 26. This work shows the high prevalence of GJB2 mutations in the Argentinean population, with frequencies that are comparable to those of the Mediterranean area. Most important, it adds two novel GJB2 mutations to be taken into consideration in the genetic diagnosis of non-syndromic sensorineural hearing loss.