Genes causing clefting syndromes as candidates for non-syndromic cleft lip with or without cleft palate: a family-based association study.

Clefts of the orofacial region are among the most common congenital defects, caused by abnormal facial development during gestation. Non-syndromic cleft lip with or without cleft palate (NSCLP) is a complex trait most probably caused by multiple interacting loci, with possible additional environmental factors. As facial clefts form part of more than 300 syndromes, one strategy for identifying the genetic causes of NSCLP could be to study candidate genes responsible for clefting syndromes. Three genes were selected for this investigation: TP63, which codes for the tumour protein p63 and causes Ectrodactyly-Ectodermal dysplasia-orofacial Cleft syndrome; JAG2, a downstream gene of TP63; and MID1, which is responsible for Opitz syndrome. A linkage disequilibrium investigation was performed with intragenic single nucleotide polymorphisms on each of these genes in a sample study of 239 patients/parents trios. Evidence which suggests that JAG2 and MID1 may play a role in NSCLP was obtained.