The risk of nonsyndromic cleft lip with or without cleft palate and Vax1 rs7078160 polymorphisms in southern Han Chinese

Introduction: Non-syndromic cleft lip with or without cleft palate is a common worldwide birth defect due to a combination of environmental and genetic factors. Genome-wide association studies reported the rs7078160 of Vax1 is closely related to non-syndromic cleft lip with or without cleft palate in European populations. The following studies showed the same results in Mongolian, Japanese, Filipino, Vietnamese populations etc. However, conflicting research had been reported in Chinese population, OBJECTIVE: The aim of this study was to investigate the association between the rs7078160 polymorphism and non-syndromic cleft lip with or without cleft palate in Southern Chinese patients.

Methods: In this study, we investigated the polymorphism distribution of rs7078160 in 100 complete patient trios (39 patients with non-syndromic cleft lip and palate; 36 patients with non-syndromic cleft lip only; 25 had non-syndromic cleft palate only; and their parents) from Southern ethnic Han Chinese. 60 healthy trios were selected as control. Polymerase chain reaction and Sanger sequencing were used to genotype rs7078160 in Vax1; both case-control and family-based associations were analyzed.

Results: The case-control analyses revealed the rs7078160 polymorphism was significant, associated with non-syndromic cleft lip with or without cleft palate (p=0.04) and non-syndromic cleft lip and palate (p=0.01), but not associated with non-syndromic cleft lip only and non-syndromic cleft palate only patients. The genotype composition of rs7078160 comprises mutated homozygous AA, heterozygous AG and wild homozygous GG. Cases with AG+AA genotypes compared with GG homozygotes showed an increased risk of non-syndromic cleft lip with or without cleft palate (p=0.04, OR=2.05, 95% CI: 1.01-4.16) and non-syndromic cleft lip and palate (p=0.01, OR=3.94, 95% CI: 1.34-11.54). In addition, we did not detect any transmission-disequilibrium in rs7078160 (p=0.68).

Conclusion: This study suggests that rs7078160 polymorphism is a risk factor of non-syndromic cleft lip with or without cleft palate, and Vax1 is strongly associated with non-syndromic cleft lip with or without cleft palate in Southern Chinese Han populations.