The scientists were part of a team of researchers at the West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) at UG.
The researchers collected samples from children in the 11 schools for the deaf across the country.
The scientists randomly screened 145 Ghanaians and found out that there was a 1.4% carrier frequency rate among them. This means that out of every 145 Ghanaians two are likely to carry the defective gene that can be passed on to their children.
The gene is known as the Gap junction beta 2 (GJB2) or Connexin 26. It directs the production of proteins that make up part of the inner ear.
The research also showed that the gene is recessive and therefore carriers of the gene, who inherit just one defective copy from a parent, have normal hearing. However, those who inherit two flawed copies (one from each parent) have a hearing impairment that can range from moderate to profound.
This Ghana-led research is one of the many advances that will make it possible to offer genetic testing in Ghana. It will further help people find out why their families have a hearing impairment and also to check the spread of the gene.
The study reviewed 1,104 medical reports of the selected students in the 11 schools for the deaf.
They identified that out of those selected 97 families had at least two members living with the hearing condition and 166 individuals did not have any family history of the impairment.
A medical geneticist and an ear, nose, and throat (ENT) specialist reviewed the record of each participant. The blood samples of the participants were taken from all available family members. DNA was also extracted from their blood samples.
The researchers looked for mutation of the Connexin 26 gene. It was earlier identified in 2001 when over 50% or more cases of inherited deafness in the 11 schools for the deaf in Ghana and the Adamorobe village near Aburi, were linked to it.
The scientists also looked for the GJB2 and GJB6 variants in the blood samples of the 97 families with the hearing impairment and the 166 single cases identified.
The field research was conducted by a Doctor of Philosophy (Ph.D.) candidate, Samuel Mawuli Adadey. It was approved by the Noguchi Memorial Institute for Medical Research Ethical Review Board and the Special Education Unit of the Ghana Education Service.
It was supervised by a biochemist at the University of Ghana, Professor Gordon A. Awandare, a medical geneticist at the University of Cape Town in South Africa, Prof. Ambroise Wonkam, and an expert in Audiology at the Korle Bu Teaching Hospital, Prof. Geoffrey Amedofu.
The research showed that the GJB6 gene, which was found globally, was absent in the Ghanaian cases. However, the GJB2-R143W gene was found to be responsible for over a quarter of familial hearing impairment cases among the groups that were screened.
This implied that one out of every four families with deafness would have the “gene-mistake”. The study, therefore, indicated that the number of hearing-impaired patients in Ghana could marginally increase if this gene was not checked.