RESUMEN
BACKGROUND: Non-syndromic cleft lip with or without cleft palate (NSCLP) is a common malformation. The aetiology is multifactorial. An incidence of 1.1-1.39 per 1000 new births had been reported in Mexico. The folic acid intake in preconceptional stage has been reported to prevent malformations such as neural tube defects (NTD) and NSCLP. The C677T variant of the methylene-tetrahydrofolate reductase (MTHFR) gene is responsible of a thermolabile form, related to decrease of folate and increase homocysteine. This variant has been associated with CLP, in different populations, but results are still controversial. Our objective was to determine the allelic (AF) and genotypic frequency (GF) of the MTHFR-C677T variant in Mexican children with NSCLP. METHODS: Transverse comparative study in 67 Mexican children with NSCLP and a control group with 70 unrelated Mexican individuals without NSCLP. RESULTS: The AF in NSCLP was 39 %. There was no statistical difference between AF in the two groups (39 versus 41). CONCLUSIONS: In this population, genotype C677T was not a major risk factor for this malformation, however, sample size, other genes implicated and genes-environment interactions must be considered.