Abstract:
This study aimed to investigate GJB2 (connexin 26) and GJB6 (connexin 30) mutations
associated with familial non-syndromic childhood hearing impairment (HI) in Cameroon. We selected
only families segregating HI, with at least two a ected individuals and with strong evidence of
non-environmental causes. DNA was extracted from peripheral blood, and the entire coding region
of GJB2 was interrogated using Sanger sequencing. Multiplex PCR and Sanger sequencing were
used to analyze the prevalence of the GJB6-D3S1830 deletion. A total of 93 patients, belonging to
41 families, were included in the analysis. Hearing impairment was sensorineural in 51 out of 54
(94.4%) patients. Pedigree analysis suggested autosomal recessive inheritance in 85.4% (35/41) of
families. Hearing impairment was inherited in an autosomal dominant and mitochondrial mode
in 12.2% (5/41) and 2.4% (1/41) of families, respectively. Most HI participants were non-syndromic
(92.5%; 86/93). Four patients from two families presented with type 2 Waardenburg syndrome,
and three cases of type 2 Usher syndrome were identified in one family. No GJB2 mutations were
found in any of the 29 families with non-syndromic HI. Additionally, the GJB6-D3S1830 deletion was
not identified in any of the HI patients. This study confirms that mutations in the GJB2 gene and the
del(GJB6-D13S1830) mutation do not contribute to familial HI in Cameroon.
