Abstract

Orofacial clefts [cleft lip (CL), cleft palate (CP), and cleft lip and palate (CLP)] are the most common orofacial congenital malformations found among live births, accounting for 65% of all head and neck anomalies. Due to conflicting information on the epidemiology of cleft deformities in African populations, this study was conducted to describe the epidemiology and patterns of orofacial clefts in Tanzania. This thesis also identified and described aspects of facial shape that vary most among normal population of children and between different ethnicities. The established baseline data for normal facial shape variation that can serve as phenotypic basis in genetic association studies to identify genes for orofacial clefts. Lastly, we also compared facial shape between noncleft children and children with repaired/unrepaired orofacial cleft in order to identify aspects of facial shape that differ most. In order to describe the epidemiology of orofacial clefts, a hospital-based retrospective descriptive study was conducted to identify all children with the disease attended or treated from 2004 to 2009. Comparison of facial shape in the general population and in individuals with orofacial clefts was carried using three-dimensional imaging system in combination with geometric morphometric analysis techniques. Isolated cleft lip was found to be the most common cleft type, followed by clefts of both the lip and palate, a pattern broadly similar to other series in African countries, and different from the distribution of orofacial clefts in low and middle income countries in other parts of the world. We also found a significant face shape differences within the population of normal Tanzanian children that were localized to specific regions of the face. Some of these facial shape differences manifested in ethnic-specific manner. Facial shape in noncleft children was also found to be significantly different from both children with repaired and unrepaired orofacial clefts of the same sex, age and ethnic group. Facial phenotypes that have been identified both in the general population and in affected individuals in this study might be used in genetic association and linkage analyses to identify risk markers for orofacial clefting.