<i>GJB2</i> and <i>GJB6</i> Mutations in Hereditary Recessive Non-Syndromic Hearing Impairment in Cameroon

• Main Authors: Edmond Tingang Wonkam, Emile Chimusa, Jean Jacques Noubiap, Samuel Mawuli Adadey, Jean Valentin F. Fokouo, Ambroise Wonkam
• Format: Article
• Language: English
• Published: MDPI AG 2019-10-01
• Series: Genes
• Subjects: hearing impairment; genetics; <i>gjb2</i> and <i>gjb6</i>; cameroon; africa
• Online Access: https://www.mdpi.com/2073-4425/10/11/844

This study aimed to investigate <i>GJB2</i> (connexin 26) and <i>GJB6</i> (connexin 30) mutations associated with familial non-syndromic childhood hearing impairment (HI) in Cameroon. We selected only families segregating HI, with at least two affected individuals and with strong evidence of non-environmental causes. DNA was extracted from peripheral blood, and the entire coding region of <i>GJB2</i> was interrogated using Sanger sequencing. Multiplex PCR and Sanger sequencing were used to analyze the prevalence of the <i>GJB6</i>-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 <i>GJB2</i> mutations were found in any of the 29 families with non-syndromic HI. Additionally, the <i>GJB6</i>-D3S1830 deletion was not identified in any of the HI patients. This study confirms that mutations in the <i>GJB2</i> gene and the del(<i>GJB6</i>-D13S1830) mutation do not contribute to familial HI in Cameroon.