The 19-bp deletion polymorphism of dihydrofolate reductase (DHFR) and nonsyndromic cleft lip with or without cleft palate: evidence for a protective role.

Objective: Nonsyndromic cleft lip with or without cleft palate (NS-CL/P) are among the most common congenital birth defects worldwide. Several lines of evidence point to the involvement of folate, as well as folate metabolizing enzymes in risk reduction of orofacial clefts. Dihydrofolate reductase (DHFR) enzyme participates in the metabolic cycle of folate and has a crucial role in DNA synthesis, a fundamental feature of gestation and development.