GENETICS OF THE NONSYNDROMIC CLEFT OF THE LIP WITH OR WITHOUT CLEFT OF THE PALATE

Abstract

Nonsyndromic cleft of the lip and/or palate (CLP or orofacial cleft) derives from an embryopathy with consequent failure of the nasal process and/or palatal shelves fusion. This severe birth defect is one of the most common malformations among live births in human. Nonsyndromic CLP is composed of two separate entities: cleft lip and palate (CL+/-P) and cleft palate only (CPO). CL+/-P and CPO have a genetic background, while environmental factors play additional roles in the onset of these malformations. Several loci have been mapped in human chromosomes of patients affected by CL+/-P, whereas a specific gene has been identified. The complexity of the genetics of nonsyndromic CLP may explain the heterogeneity found in different family sets. It is possible that the distinct genes, model of inheritance, and interaction with environmental factors, account for results obtained with different approaches. Our genetic data suggest that the CLP major locus maps in 6p23, whereas other minor loci were mapped in 2q13, 19q13.2