Prevalence of orofacial clefts in Nigeria

Orofacial clefts (OFC) are the most common malformations of the head and neck. In Africa, OFC is under-ascertained with little or no surveillance system in most parts for clefts and other birth defects. A Nigerian craniofacial anomalies study “NigeriaCRAN” was established in 2006 to support cleft research specifically for epidemiological studies, treatment outcomes and; studies into etiology and prevention. We pooled data from seven of the largest Smile Train treatment centers in the six geopolitical zones in Nigeria. Data from September 2006 to June 2011 were analyzed and clefts compared between sides and gender using the Fisher’s exact test. A total of 2197 cases were identified during the study period with an estimated prevalence rate of 0.5/1000. Of the total number of OFC, 53.3% are males and 47%.7 are females. There was a significant difference (p=0.0001) between unilateral left clefts and unilateral right clefts and; significant difference (p=0.0001) between bilateral clefts and either clefts on the left or right side. A significant gender difference (p=0.03) with more females than males was also observed for CP. A total of 103 (4.7 %) associated anomalies were identified, nine syndromic cleft cases and 10.4 % of the total number of clefts individuals have an affected relative. The significant difference between unilateral clefts and gender differences in the proportion of cleft palate only are consistent with the literature. The present study emphasizes the need for birth defects registries in developing countries in order to estimate the exact prevalence of birth defects including OFC

Genetic studies in the nigerian population implicate an MSX1 mutation in complex oral facial clefting disorders

BACKGROUND: Orofacial clefts are the most common malformations of the head and neck with a World-wide prevalence of 1/700 births. They are commonly divided into CL(P) and CP based on anatomical, genetic and embryological findings. A Nigerian craniofacial anomalies study “NigeriaCRAN” was set up in 2006 to investigate the role of gene-environment interaction in the etiology of orofacial clefts in Nigeria. SUBJECTS AND METHODS: DNA isolated from saliva from the Nigerian probands was used for genotype association studies and direct sequencing on the cleft candidate genes: MSX1, IRF6, FOXE1, FGFR1, FGFR2, BMP4, MAFB, ABCA4, PAX7 and VAX1, and the chromosome 8q region. RESULTS: A missense mutation A34G in MSX1 was observed in nine cases and four hap map controls. No other apparent etiologic variations were identified. A deviation from HWE was observed in the cases (p= 0.00002). There was a significant difference between the affected side for unilateral CL (p=0.03) and, between bilateral clefts and clefts on either side (p=0.02). A significant gender difference was also observed for CP (p=0.008). CONCLUSIONS: The replication of a mutation previously implicated in other populations suggests a role for the MSX1 A34G variant in the etiology of CL(P)