Mutation and functional analysis of SUMO1, PDGFRa and miR-140 gens in non-syndromic oral clefts

Abstract

The SUMO1, PDGFRa and miR-140 have been proposed as genes in which mutations may contribute to non-syndromic cleft lip and/or cleft palate. Strong evidence supporting the significant roles of these genes comes from a chromosomal translocation causing gene disruption resulting in haploinsufficiency, a cleft phenotype in a knockout mouse experiment and an expression study during palatal development. Mutation screening of the SUMO1, PDGFRa and miR-140 genes was carried out in 227 Thai patients, 123 with cleft lip and/or palate and 104 with cleft palate only. Even though there were no potential pathogenic mutations identified in the SUMO1 and miR-140 genes, there were 3 potential pathogenic mutations identified in the 3’ untranslated region (UTR) of the PDGFRa; namely c.*34G>A, c.*51G>A and c.*480C>A. They are all within or close to the predicted binding sites for the human microRNA, miR-140. Their frequencies between cases and controls are significantly or have a tendency to be different. Functional studies of these three variants by luciferase assay revealed that, in the presence of miR-140, the c.*34G>A variant significantly repressed luciferase compared to that of the wild type. This strongly suggests the functional significance of this variant. For the first time, we showed strong evidences that PDGFRa mutations cause human oral clefts.