Missense mutations in GJB2 encoding connexin-26 cause the ectodermal dysplasia keratitis-ichthyosis-deafness syndrome

Gabriele Richard, Fatima Rouan, Colin E. Willoughby, Nkecha Brown, Pil Chung, Markku Ryynänen, Ethylin Wang Jabs, Sherri J. Bale, John J. DiGiovanna, Jouni Uitto, Laura Russell

Research output: Contribution to journalArticle

Abstract

Keratitis-ichthyosis-deafness syndrome (KID) is a rare ectodermal dysplasia characterized by vascularizing keratitis, profound sensorineural hearing loss (SNHL), and progressive erythrokeratoderma, a clinical triad that indicates a failure in development and differentiation of multiple stratifying epithelia. Here, we provide compelling evidence that KID is caused by heterozygous missense mutations in the connexin-26 gene, GJB2. In each of 10 patients with KID, we identified a point mutation leading to substitution of conserved residues in the cytoplasmic amino terminus or first extracellular domain of Cx26. One of these mutations was detected in six unrelated sporadic case subjects and also segregated in one family with vertical transmission of KID. These results indicate the presence of a common, recurrent mutation and establish its autosomal dominant nature. Cx26 and the closely related Cx30 showed differential expression in epidermal, adnexal, and corneal epithelia but were not significantly altered in lesional skin. However, mutant Cx26 was incapable of inducing intercellular coupling in vitro, which indicates its functional impairment. Our data reveal striking genotype-phenotype correlations and demonstrate that dominant GJB2 mutations can disturb the gap junction system of one or several ectodermal epithelia, thereby producing multiple phenotypes: nonsyndromic SNHL, syndromic SNHL with palmoplantar keratoderma, and KID. Decreased host defense and increased carcinogenic potential in KID illustrate that gap junction communication plays not only a crucial role in epithelial homeostasis and differentiation but also in immune response and epidermal carcinogenesis.

Original languageEnglish (US)
Pages (from-to)1341-1348
Number of pages8
JournalAmerican Journal of Human Genetics
Volume70
Issue number5
DOIs
StatePublished - 2002
Externally publishedYes

ASJC Scopus subject areas

  • Genetics

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    Richard, G., Rouan, F., Willoughby, C. E., Brown, N., Chung, P., Ryynänen, M., Jabs, E. W., Bale, S. J., DiGiovanna, J. J., Uitto, J., & Russell, L. (2002). Missense mutations in GJB2 encoding connexin-26 cause the ectodermal dysplasia keratitis-ichthyosis-deafness syndrome. American Journal of Human Genetics, 70(5), 1341-1348. https://doi.org/10.1086/339986