Analysis of the candidate genes responsible for non-syndromic cleft lip and palate in Japanese people

In order to assess the association of alleles for candidate genes with non-syndromic cleft lip and palate, DNA samples from 43 Japanese patients were compared with those from 73 control subjects with respect to the genes encoding transforming growth factor α (TGFα), TGFβ and γ-aminobutyric acid type A receptor β3 (GABRB3). The restriction fragment length polymorphisms of the 3′-non-coding region of the TGFα gene K-primer region were observed after digestion with NcoI and HinfI. Allele 4 was the most common among cases of cleft lip with or without cleft palate, whereas allele 2 was the most common among controls. A significant difference was found in this region between groups with cleft lip (with or without cleft palate) and controls (χ² = 10.190; P = 0.017). Three alleles of the TGFβ2 gene were tested, and allele 2 was the most common in both cases and controls. The proportion of allele 2 in the case group was greater than that in the control group, showing a significant difference between cases of cleft lip (with or without cleft palate) and controls (χ² = 19.208; P < 0.0001). No significant differences in variants of TGFβ3 or GABRB3 between case and control populations were observed. Thus it is concluded that TGF genes play a role in craniofacial development, and that alleles of TGFα or/and TGFβ2 are associated with cleft lip and cleft palate in Japanese populations.