A Deletion Involving the Connexin 30 Gene in Nonsyndromic Hearing Impairment

• Published in: The New England journal of medicine Vol. 346; no. 4; pp. 243 - 249
• Main Authors: del Castillo, Francisco J, del Castillo, Ignacio, Villamar, Manuela, Moreno-Pelayo, Miguel A, Álvarez, Araceli, Tellería, Dolores, Menéndez, Ibis, Moreno, Felipe
• Format: Journal Article
• Language: English
• Published: Boston, MA Massachusetts Medical Society 24.01.2002
• Subjects: Base Sequence; Biological and medical sciences; Blotting, Southern; chromosome 13; Chromosomes, Human, Pair 13; Connexin 26; Connexin 30; Connexins - genetics; DFNB1 gene; DNA Mutational Analysis; Ear, auditive nerve, cochleovestibular tract, facial nerve: diseases, semeiology; Genes; Genes, Recessive; Genetics; Genotype; GJB2 gene; Hearing loss; Hearing Loss, Sensorineural - genetics; Humans; Medical sciences; Molecular Sequence Data; Mutation; Non tumoral diseases; Otorhinolaryngology. Stomatology; Polymerase Chain Reaction; Sequence Deletion; Cuba; Spain; Human; Connexin; Gene; Etiology; Auditory disorder; ENT disease; Mutation; Molecular biology; Genetic determinism; Genetic disease; Hearing loss
• ISSN: 0028-4793; 1533-4406
• DOI: 10.1056/NEJMoa012052

Up to half of patients with congenital autosomal recessive nonsyndromic deafness have mutations in the gene encoding the gap-junction protein connexin 26 ( GJB2 ); the rest have had no identifiable mutations. In this study, patients with this form of deafness who had one mutant GJB2 allele were found to have a novel 342-kb deletion that truncates the gene encoding another gap-junction protein, connexin 30 ( GJB6 ). Twenty-two of the 33 subjects studied were heterozygous for both mutations and 2 were homozygous for the GJB6 mutation. Homozygous mutations in either GJB2 or GJB6 or heterozygous mutations in both genes can result in prelingual deafness. Hearing impairment affects about 1 in 1000 newborns. 1 Cases that are present before the development of speech (prelingual onset) hamper speech acquisition and, therefore, normal communication and social integration. Early detection is essential for the application of palliative treatments and special education. Since about 50 percent of the cases of hearing impairment have genetic causes, 1 molecular diagnosis and genetic counseling are needed. However, the main obstacle to molecular diagnosis is the extreme genetic heterogeneity of nonsyndromic hearing impairment. Most cases of genetic deafness are autosomal recessive. So far, 28 loci for autosomal recessive nonsyndromic hearing impairment have been identified, which . . .