In search of genetic markers for nonsyndromic deafness in Africa: a study in Cameroonians and Black South Africans with the GJB6 and GJA1 candidate genes.
Deafness is the most common sensory disability in the world and has a variety of causes. Globally, mutations in GJB2 have been shown to play a major role in nonsyndromic deafness, but this has not been seen in Africans. Two other connexin genes, GJB6 and GJA1, have been implicated in hearing loss but have seldom been investigated in African populations. We set out to investigate the role of genetic variation in GJB6 and GJA1 in a group of Cameroonian and South African Blacks with nonsyndromic recessive hearing loss. A subset of 100 patients, affected with nonsyndromic hearing loss, from a cohort that was previously shown not to have GJB2 mutation, was analyzed by Sanger sequencing of the entire coding regions of GJB6 and GJA1. In addition, the large-scale GJB6-D3S1830 deletion was also investigated. No pathogenic mutation was detected in either GJB6 or GJA1, nor was the GJB6-D3S1830 deletion detected. There were no statistically significant differences in sequence variants between patients and controls. Mutations in GJB6 and GJA1 are not a major cause of nonsyndromic deafness in this group of Africans from Cameroon and South Africa. Currently, there is no sufficient evidence to support their testing in a clinical setting for individuals of African ancestry.
1 Division of Human Genetics, Department of Clinical Laboratory Sciences, Faculty of Health Sciences, University of Cape Town , Cape Town, South Africa .
Jason
J
Bosch
Kamogelo
K
Lebeko
Jean Jacques Noubiap
JJ
Nziale
Collet
C
Dandara
Nomlindo
N
Makubalo
Ambroise
A
Wonkam
D000293:Adolescent; D017668:Age of Onset; D044383:Black People / Q000235:genetics*; D002163:Cameroon; D002648:Child; D000072259:Connexin 26; D000075302:Connexin 30; D018031:Connexin 43 / Q000235:genetics*; D017630:Connexins / Q000235:genetics*; D003638:Deafness / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D005260:Female; D017353:Gene Deletion; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008297:Male; D055815:Young Adult
D000075302:Connexin 30; D018031:Connexin 43; D017630:Connexins; C500216:GJA1 protein, human; C000607042:GJB2 protein, human; C491020:GJB6 protein, human; D005819:Genetic Markers; D000072259:Connexin 26