| Objectives:1. To explore the risk factors of susceptibility of non-syndromic cleft lip with or without cleft palate (NSCL/P) in Liuzhou City, Guangxi.2. To explore the variable contribution of the TaqI、BamHI and Rsal polymorphisms in TGFa gene to NSCL/P.3. To explore the variable contribution of rs142167(A/G) and rs3809857(G/T) polymorphisms in Wnt3gene to NSCL/P.4. To assess the gene-environment interaction on risk of NSCL/P.Methods:A matched case-control study was performed in this study. The study population consisted of178cases with NSCL/P and178controls without any birth defects born in Guangxi between2007and2012. A questionnaire survey was carried out to detect the information on maternal and paternal exposure before and during pregnancy. The samples of DNA were extracted from the peripheral blood of all children. The Genotypes of TaqI, BamHI, RsaI in TGFa gene and rs142167, rs3809857in Wnt3gene of178pairs subjects were determined by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP). McNemar test, univariate and multiple conditional logistic regression models were used to explore the association between environmental factors, different genotypes and the risk of NSCL/P. Additionally, the gene-environment interaction was assessed by conditional logistic regression models. The odds ratio values (ORs) was calculated by using regression model to determine the addition effects among different factors and measure the interaction. All data analyses were performed using the statistical software package SPSS13.0(SPSS, Chicago, IL). A2-tailed P value<0.05was considered statistically significant.Results:1. In total,178pairs subjects with NSCL/P children as case and healthy children as control were enrolled in this study. Among them,121pairs were boys and57pairs were girls. The cleft subtype ratio was1:1.49for cleft lip only with cleft lip and palate, and1:0.87for cleft lip only with cleft palate only.2. Risk factors in environmentThe results of multiple conditional logistic regression analysis indicated that living in rural area(OR:2.35;95%CI:1.10,5.05), keeping pets before six months to the early stages of pregnancy (OR:4.46;95%CI:1.46,13.66), passive smoking before six months to the early stages of pregnancy (OR:2.20;95%CI:1.28,3.77), threatened abortion (OR:20.84;95%CI:1.42,304.85), chronic disease history of mother (OR:31.84;95%CI:3.20,316.60), family history of birth defects (OR:11.14;95%CI:1.30,95.75) and father’s occupational exposure to physical adverse factors of father (OR:4.62;95%CI:1.10,19.47) were risk environment factors of NSCL/P. However, if supplement folic acid before six months to the early stages of pregnancy (OR:0.30;95%CI:0.10,0.91) and the higher educational level of father (OR:0.14;95%CI:0.03,0.62), the risk of NSCL/P of their offsprings would decrease.3. Gene polymorphisms3.1The results suggested that TGFa gene TaqI polymorphism could be used as a genetic susceptibility marker for NSCL/P. Infants carrying the rarer C2allele showed a1.82-fold increase in risk for NSCL/P (OR:1.82;95%CI:1.13,2.91, P=0.013). C1C2or C2C2genotype was significantly associated with increased risk of NSCL/P compared with C1C1genotype (OR C1C2+C2C2vs C1C1:1.84;95%CI:1.10,3.10, P=0.020).3.2The results suggested that TGFa gene BamHI polymorphism could be used as a genetic susceptibility marker for NSCL/P. Infants carrying the rarer Al allele showed a two-fold increase in risk for NSCL/P (OR:2.00;95%CI:1.30,3.06, P=0.002). A1A2or A1A1genotype was significantly associated with increased risk of NSCL/P compared with A2A2genotype (OR A1A1+A2A2vs A2A2:2.19;95%CI:1.37,3.50, P=0.001).3.3The results suggested that TGFa gene RsaI polymorphism could be used as a genetic susceptibility marker for NSCL/P. No association was found between the rarer Al allele and risk for NSCL/P in our data (OR:1.38;95%CI:0.89,2.14, P=0.149). Nevertheless, under a recessive genetic model, B1B1genotype was significantly associated with increased risk of NSCL/P compared with B1B2+B2B2genotype (OR B1B1vs B1B2+B2B2:3.42,95%CI:1.29,9.06, P=0.014).3.4The results suggested that Wnt3gene rs142167polymorphism could be used as a genetic susceptibility marker for NSCL/P. Infants carrying the rarer G allele showed a1.65-fold increase in risk for NSCL/P (OR:1.65;95%CI:1.15,2.34, P=0.006). Under a recessive genetic model, GG genotype was significantly associated with increased risk of NSCL/P compared with AG or AA genotype (OR GG vs AG+AA:2.64;95%CI:1.03,6.76, P=0.043).3.5No significant association was detected when cases and controls were compared with the genotype for Wnt3gene rs3809857polymorphism in risk of NSCL/P.4. Gene-environment interaction between TGFa, Wnt3gene polymorphisms and environmental factors4.1The positive additive interactions were found between TGFa gene TaqI polymorphism and passive smoking and alcohol use before six months to the early stages of pregnancy, threatened abortion, family history of birth defects and father’s occupational exposure to physical adverse factors. Similarly, a positive additive interaction was found between TGFa gene BamHI polymorphism and keeping pets and no folic acid supplement before six months to the early stages of pregnancy and father’s occupational exposure to physical adverse factors. Aslo, a positive additive interaction was found between TGFa gene RsaI polymorphism and alcohol use before six months to the early stages of pregnancy, threatened abortion and father’s occupational exposure to physical adverse factors.4.2The positive additive interactions were found between Wnt3gene rs142167polymorphism and no folic acid supplement before six months to the early stages of pregnancy, alcohol use before six months to the early stages of pregnancy, threatened abortion, family history of birth defects of mother and father’s occupational exposure to physical adverse factors. Similarly, the positive additive interactions were found between Wnt3gene rs3809857polymorphism and keeping pets, no folic acid supplement, passive smoking before six months to the early stages of pregnancy, threatened abortion and father’s occupational exposure to physical adverse factors.Conclusions:1. Our findings demonstrated that living in rural area, keeping pets before six months to the early stages of pregnancy, passive smoking before six months to the early stages of pregnancy, threatened abortion, chronic disease history of mother, family history of birth defects and father’s occupational exposure to physical adverse factors of father were risk environment factors of NSCL/P. However, supplement folic acid before six months to the early stages of pregnancy and the higher educational level of father were protective factors of NSCL/P.2. Our findings support the contribution of TGFα gene TaqI, BamHI, RsaI polymorphism and Wnt3gene rs142167polymorphism in the etiology of NSCL/P in the population of Liuzhou City, Guangxi. And no association was found between the Wnt3gene rs3809857polymorphism and the risk of NSCL/P in our data. But these results warrant further investigation.3. There are obvious interactions between TGFα gene TaqI, BamHI and Rsal polymorphisms and environmental factors such as passive smoking, alcohol use and keeping pets before six months to the early stages of pregnancy, family history of birth defects and father’s occupational exposure to physical adverse factors.4. There are obvious interactions between Wnt3gene rs142167and rs3809857 polymorphisms and environmental factors such as no folic acid supplement, passive smoking, alcohol use, and keeping pets before six months to the early stages of pregnancy, threatened abortion, family history of birth defects and father’s occupational exposure to physical adverse factors.5. NSCL/P is caused by the interactions between many minor genes and environmental risk factors. It is very important to study their correlation to classify the risk factors and pathogenesis of NSCL/P. |
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