A novel connexin 26 gene mutation associated with features of the keratitis-ichthyosis-deafness syndrome and the follicular occlusion triad.
We report the case of a congenitally deaf white male with mild palmoplantar keratoderma, ichthyosiform scaling, follicular hyperkeratosis, and mild keratitis, features consistent with keratitis-ichthyosis-deafness syndrome. His major problem was severe, disfiguring, inflammatory dissecting folliculitis of the scalp, hidradenitis suppurativa, and cystic acne, features comprising the follicular occlusion triad. This unusual phenotype is associated with a novel heterozygous point mutation (C119T) in the gap junction beta2 gene that substitutes a valine for alanine at codon 40 (A40V) in the connexin 26 protein. Through Xenopus oocyte expression studies, this mutant protein was shown to significantly disrupt the function of the specialized gap junctions connecting the cytoplasm of adjacent cells critical for tissue homeostasis. Mutations within the connexin 26 protein are associated with syndromes involving both sensorineural deafness and hyperkeratotic skin disorders. This is the first report of an association between a connexin 26 protein mutation, follicular hyperkeratosis of keratitis-ichthyosis-deafness syndrome, and severe follicular occlusion triad.
Montgomery
Jay R
JR
USN, National Naval Medical Center, Bethesda, Maryland 20889, USA. jrmontgomery@bethesda.med.navy.mil
White
Thomas W
TW
Martin
Bryan L
BL
Turner
Maria L
ML
Holland
Steven M
SM
D000152:Acne Vulgaris / Q000235:genetics / Q000601:surgery; D000293:Adolescent; D019943:Amino Acid Substitution; D000818:Animals; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D004252:DNA Mutational Analysis; D007644:Darier Disease / Q000235:genetics*; D003646:Debridement; D005499:Folliculitis / Q000235:genetics*; D017629:Gap Junctions / Q000502:physiology / Q000648:ultrastructure; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006579:Heterozygote; D017497:Hidradenitis Suppurativa / Q000235:genetics*; D006801:Humans; D007057:Ichthyosis / Q000235:genetics*; D007634:Keratitis / Q000235:genetics*; D008297:Male; D008564:Membrane Potentials; D020125:Mutation, Missense; D009865:Oocytes; D017354:Point Mutation; D016038:Skin Transplantation; D013577:Syndrome; D014162:Transfection; D014982:Xenopus laevis
D017630:Connexins; C000607045:GJB2 protein, Xenopus; D000072259:Connexin 26