Characteristics of polymorphism in promoter region of insulin-like growth factor-1 gene in 561 neonates / 中华围产医学杂志

ABSTRACT

Objective To investigate polymorphism in the promoter region of insulin-like growth factor-1(IGF-1) gene.Methods Five hundred and sixty-one neonates admitted to Peking University Third Hospital from June 1st,2010 to June 30th,2012 were recruited into the study.Gender,gestational age,birth weight and birth length were collected.Heel blood samples were collected on 3-5 days after birth.DNA was extracted to analyze the polymorphism in the promoter region of IGF-1 gene.Chi-square test,independent-sample t-test,analysis of variance and HardyWeinberg equilibrium were performed.Results Among the 561 neonates,413 were full term,and 148 were preterm; 92 were large for gestational age (LGA),433 were appropriate for gestional age (AGA),and 36 were small for gestional age (SGA).Seven different alleles and 23 genotypes in the promoter region of IGF-1 gene were identified in the population.The seven alleles were 188,190,192,194,196,198 and 200 bp respectively.The three most common genotypes were 190-192 bp,192-196 bp and 192-192 bp,whose frequencies were 23.2％ (130/561),15.0％ (84/561) and 12.8％(72/561).There were no significant differences of cytosine-adenosine (CA)19/CA19,CA19/CAno19and CAno19/CAno19 genotypes between full term and preterm infants [11.4％ (47/413) vs 16.9％(25/148),55.9％ (231/413) vs 50.7％ (75/148) and 32.7％ (135/413) vs 32.4％ (48/148)respectively,x2=2.96,1.21 and 0.00,all P＞0.05].There was no difference in the gestional age among infants with CA19/CA19,CA19/CAno19 and CAno19/CAno19 genotypes [(37.1±2.9),(37.6±3.1) and (37.4±3.1) weeks respectively,F=0.54,P=0.58].The frequency of CA19/CA19 in SGA neonates was higher than that in LGA and AGA neonates [25.0％ (9/36) vs 7.6％(7/92) and 12.9％ (56/433),x2 =7.01,P=0.03],but there were no differences in the frequency of CA19/CAno19 and CAno19/CAno19 among LGA,AGA and SGA neonates (CA19/CAno19x2 =1.13,P=0.57; CAno19/CAno19x2 =0.58,P=0.75).Conclusions Polymorphism exists in the promoter region of IGF-1 gene.The gestational age is not associated with the frequency of CA19 allele.