Molecular Epidemiology Study On IGF Ⅰ, IGF Ⅱ, IGFBP 3 Gene Polymorphism And Gestational Age Children In Chinese Population

In recent years, birth weight of newborn is increasing with the improvement of living standards and enhanced awareness of nutrition. Studies from foreign coutries also have shown that it becomes a long-term trend for growth that the rise of the birth weight. High birth weight can lead to not only complications during delivering such as brachial plexus palsy, intracranial hemorrhage, fetal distress, neonatal asphyxia, maternal injury and so on, but also diabetes mellitus, obesity, coronary heart disease which occur at adulthood.Fetal growth and the birth weight of neonatal are related to biological factors,as well as life style during pregnancy, intake of nutritional and other environmental factors. Gene is the most important factor that affects fetal growth firstly.Insulin-like growth factor system (IGF) is highly homologous with insulin.In this system, the IGFⅠ, IGFⅡand IGFBP 3 are the important symboles of embryonic growth and development. Their expressions also indicate the stage of human growth and development,and are closely associated with birth weight.So,it is suggested that the genotype of three genes can lead to the raise of newborns birth weight. In this study,we researched the the relationship between IGFⅠ, IGFⅡ,IGFBP 3 gene polymorphisms and the large for gestaional age infant(LGA),based on the case-control study in Nanjing, Jiangsu.This research is helpful for clarifying the mechanism and discovering the related genotype of LGA in Chinese people.Through this study,it is meaningful that we can give reasonable intervention programs and recommendations to the populations carrying different genotypes.[Objective] To investigate whether the gene polymorphism of IGF I rs6214 and rs35767, IGF II rs2585 and rs3110697, IGFBP 3 rs3110697 are associated with large for gestational age infants (LGA).[Methods] In this case-control study,368 neonates (180 large for gestational age infants and 188 appropriate for gestational age infants) were selected in Nanjing of Jiangsu Province.All the neonates were genotyped for 5 genetic polymorphism sites by a polymerase chain reaction-restriction fragment length polymorphism assay(PCR-RFLP).Linear regression models were used to estimate the association of the genetic polymorphisms with LGA.Analysis of variance was used to compute the diffrence of anthropometrics variables .[Results] Between the LGA and AGA,the difference of distributions of the IGFⅠrs35767 genotype was significant(χ~2=9.554,P=0.008). Compared with CC genotype, CT heterozygous of IGFⅠrs35767 was associated with significantly increased risk of LGA(adjusted OR=2.136,95%CI=1.3 38-3.409), CT/TTgenotype was also associated with significantly increased risk of LGA(adjusted OR=1.936,95%CI =1.232-3.0 41). The average birth weights among the IGFⅠrs35767 genotypes were significantly different (P=0.028), besides, comparing with CC and TT carriers, the mean birth weight of CT carriers was higher (P=0.033,0.037).We did not find the releationship between the other 4 sites and risk of LGA. Among the female newborns, the mothers who did not suffer from gestational diabetes, and mothers with educational background beyond college, IGFⅠrs35767 CT/TT genotype could increase the risk of LGA significantly(adjusted OR=2.196, 1.793,2.186,95%CI = 1.019-4.737,1.108-2.903,1.296-3.685).[Conclusion] Our findings suggest that IGFⅠrs35767 polymorphism may modulate the risk of LGA.The polymorphisms of IGFⅠrs6214, IGFⅡrs2585, IGFⅡrs3802971 and IGFBP 3 rs3110697 are not contribute to LGA.