Non-Random Distribution of Human Orofacial Clefts in Ghana: Gene-Environment Interactions

Abstract

Human orofacial clefts (OFCs) are congenital anomalies that result from the breakdown of normal mechanisms that regulate the formation of the human face. They could be syndromic or non-syndromic, with a global incidence of 1:700 per live births. Environmental and genetic factors are thought to play various roles in the aetiology of OFCs. This study seeks to establish the diversity, distribution and pattern of inheritance of OFCs as well as environmental and other risk factors associated with OFCs in a Ghanaian population. A family-based, descriptive cross-sectional study that employed an interview-based survey questionnaire was used to obtain information from 467 families with history of OFCs. We employed chi-square statistics to analyse the data and used graphs to interpret the data. All previously reported subphenotypes of OFCs were observed by the present study. Clinically, about 12% of clefts in the study population were syndromic. The most common syndromic forms observed were Pierre Robin Sequence, cleft-with-club foot abnormalities and Van der Woude Syndrome. Only about 5% of clefts in the study cohort were familial. The study also established that lower level of education of parents, poverty, late antenatal care and dietary folate deficiency are major environmental factors associated with clefts in the Ghanaian population. In conclusion, OFCs are non-randomly distributed in Ghana and folate deficiency could likely be a source of genetic mutations and “epimutations” that cause OFCs, since folate is essential for DNA methylation, replication and repair as well as histone modification.