Genetic Variants at the rs4720169 Locus of TBX20 and the rs12921862 Locus of AXIN1 May Increase the Risk of Congenital Heart Defects in the Mexican Population: A Pilot Study

Abstract

Background:

Congenital heart defects (CHDs) are the most common type of birth defects and a major cause of infant mortality. Although knowledge of genetic risk variants for CHDs is scarce, most cases of CHDs are considered to be due to multifactorial inheritance.

Objective:

To analyze the association of 14 single nucleotide polymorphic variants previously associated with a risk of CHDs in a Mexican population with isolated CHDs.

Materials and Methods:

DNA samples obtained from healthy subjects and from subjects with isolated atrial, ventricular, or atrioventricular septal defects living in Northeastern Mexico were analyzed by real time-polymerase chain reaction for allelic discrimination of genetic variants of the genes TBX1, TBX20, ASTX-18-AS1, AXIN1, MTHFR, NKX2.5, BMP4, and NFATc1. The odds ratios (ORs) for allele and genotype frequencies and inheritance models were obtained.

Results:

Forty-two patients and 138 controls were included. Two variants were found to confer a risk of CHDs: variant rs4720169 of TBX20 in which the OR for the heterozygous state was 1.88 (95% confidence interval [CI]: 1.12-3.14, p = 0.010), whereas the OR for the homozygous state was 3.82 (95% CI: 1.18-12.3, p = 0.010); and variant rs12921862 of AXIN1 in which the OR for the heterozygous state was 4.15 (95% CI: 2.42-7.10; p ≤ 0.001), whereas the OR for the homozygous state was 9.2 (95% CI: 1.31-64.7, p = 0.008) for allele A.

Conclusion:

Genetic variants of the TBX20 and AXIN1 genes confer a significantly increased risk of congenital septal heart defects in a population from Northeastern Mexico.