MOLECULAR GENETIC STUDY OF THE IMPACT OF SNP C677T OF THE GENE MTHFR IN THE DEVELOPMENT OF CONGENITAL ISOLATED CLEFT LIP AND PALATE

Aim. This research was designed to conduct an associative population genetic study for the consideration of the impact of SNP C677T of the gene MTHFR in the congenital maxillofacial developmental anomalies (CMDA): congenital cleft lip (CCL), congenital cleft palate (CCP), congenital cleft lip and palate (CCLP) in the Krasnodar territory. The aim of the study is to establish the associations between SNP C677T of the gene MTHFR and the development of congenital cleft lip and/ or palate.

Materials and methods. In this research, the peculiarities of distribution of SNP C667T of the gene MTHFR in children with congenital cleft lip and/or palate (n=223) and their mothers (n=78) in comparison with the control group (n=124) were studied in the Krasnodar territory. The genetic demographic questionnaires were gathered for children with CMDA, the information about diagnosis was obtained from the medical records. The biological samples, including blood or scrapings of oral mucosa, were collected from children with the pathology and their mothers. The DNA was extracted from the samples by the standard method. The study of the peculiarities of distribution of alleles of SNP C677T of the gene MTHFR was performed by PCR-PFLP with endonuclease Hinf I or by tetra-primer ARMS-PCR method in children with CCL, CCP, CCLP, their mothers and the control group. Statistical processing of the obtained data was performed by the algorithms of the “Statistica” program.

Results. While comparing the profiles of frequencies of SNP C677T in children with CCL, CCP and CCLP with the control group, there were identified no significant differences in the frequency of this SNP and no peculiarities of genotypes distribution. There was identified a significant difference in the peculiarities of genotypes distribution with the control group (G=19,5232, d.f.=1, p<0,001) as well as united genotypes (С/C и С/T) in accordance to T/T (G=10,4657, d.f.=1; p<0,001) and united genotypes (C/T и T/T) in accordance to C/C (G=15,1896, d.f.=1, p<0,001) for the mothers of children with CCL, CCP and CCLP.

Conclusion. As a result of the study, we established the association of SNP C677T of the MTHFR gene with the development of congenital cleft lip and/or palate: mothers’ T/T genotype is associated with the increased risk of giving birth to a child with CCL, CCP and CCLP (in comparison with mothers with C/C+C/T genotype): odds ratio [OR]=16,63, 95% CI: 3,86-71,71; p=0,0003 and also for mothers with genotypes (C/T+T/T) in comparison with mothers with genotypes C/C: OR=3,22, CI:1,71-6,08; p=0,0002. The amount of risk is not significant in children with CMDA for T/T genotype. So it is possible to make a conclusion about the impact of C677T of the gene MTHFR in the development of CCL, CCP and CCLP only in mother’s genotype.