IRF6 and cleft palate: A study including a Norwegian population (377 patients with isolated cleft lip with or without cleft palate, 196 patients with isolated cleft palate, and 763 healthy subjects) showed a reduced risk (OR = 0.38, p < 0.001) of isolated cleft lip with or without cleft palate in the presence of the rs2235371 (V274I) genotype, also located in the IRF6 gene.