Addressing hearing impairment in Ghana

Samuel M. Adadey is a geneticist and a Fellow of the West African Centre for Cell Biology of Infectious Pathogens (WACCBIP) based at the University of Ghana. WACCBIP is one of the eleven Developing Excellence, Leadership, and Training in Science in Africa (DELTAS Africa) programmes, which fund Africa-based scientists to amplify the development of world-class research and scientific leadership on the continent while strengthening African institutions. DELTAS Africa is implemented through the Alliance for Accelerating Excellence in Science in Africa (AESA), a funding, agenda-setting programme management initiative of the African Academy of Sciences (AAS), the African Union Development Agency (AUDA-NEPAD), founding and funding global partners, and through a resolution of the summit of African Union Heads of Governments. DELTAS Africa is supported by Wellcome and the United Kingdom Foreign, Commonwealth and Development Office (FCDO, formerly DFID).

Motivation for my research

Most parts of Africa are burdened with severe genetic disorders which reduce the quality of life of people who are affected. Despite the high prevalence of genetic disease on the continent, very few African geneticists have been trained to investigate these disorders with the goal of proposing meaningful context-specific solutions for them. This was a motivation for me to study human genetics at the University of Ghana under a DELTAS Africa Ph.D. fellowship. My specific interest was solidified after visiting schools for the deaf and the homes of more than 80 Ghanaian families affected in some measure by hearing impairment. Most of these families had no knowledge of the genetic causes of hearing impairment, a condition which had in many communities been shrouded in mysticism and myth. I was deeply touched by the sense of helplessness in these underserved communities whose inhabitants are far removed from any potential sources of factual information about the conditions they face.

Genetics of hearing impairment in Ghana

“Genetics of hearing impairment” is one of the neglected research areas in Africa and especially in Ghana; the most recent study before the start of our project was in 2001. To draw attention to the genetics of hearing impairment in the country, in 2017 I led our research group to write and publish a systematic review on the public health burden of hearing impairment in Ghana, which expanded on the need for genomics research to identify genetic markers associated with the condition. Since then, I have used targeted and next-generation sequencing approaches to investigate the genetic causes of hearing impairment in Ghana and other African countries.

My research has identified a previously reported founder mutation (GJB2-R143W) that accounts for over a quarter of inheritable hearing impairment cases in Ghana. Our study estimated for the first time its carrier frequency at 1.4% of the hearing population relatively high. To reduce the burden of the condition, our team has started public and policy engagement to create awareness for the genetics of hearing impairment as well as to receive input from the public. I designed a diagnostic test with high sensitivity and specificity to screen newborn babies for common hearing impairment mutations within the Ghanaian population. In addition, we are generating and analysing exome data to identify novel hearing impairment gene variants in the country. Our research published in Frontiers in Genetics resulted in a report in the Daily Graphic, Ghana’s largest newspaper.

Another challenge has been that the definition of hearing impairment and its related terms vary among individuals and research groups, which poses a challenge to multi-site and interdisciplinary studies across the globe. There is no comprehensive knowledge portal that clearly outlines and explains terms relating to all aspects of the disease. To help solve this problem, I joined a team of geneticists, clinicians, bioinformaticians and biomedical scientists to develop an online portal of hearing impairment ontology, which now serves as a tool to harmonise hearing impairment terms as well as enhance collaborative research across Africa and the world at large.

My research aspirations for the genetics of hearing impairment in Ghana

My chief aim is for comprehensive postnatal hearing tests to become immediately available to every child born in Ghana. Children with genetic hearing impairment can often regain their hearing when diagnosed early and provided with appropriate interventions, and therefore screening for this condition should be added to the newborn hearing screening (NHS) program in Ghana. I look forward to the day that genetic testing for hearing loss genes will be common and available to every family in Ghana.