Insulin Gene Variable Number of Tandem Repeat Genotype, Early Growth and Glucose Metabolism in Adult Life

The predisposition to type 2 diabetes is t programmed early in life and genotypespromoting survival during nutritionaladversity could increase the riskof type 2 diabetes. the insulin gene and variationin the insulin gene variable number of tandemrepeats (vntr) polymorphism has beensuggested to modify birth size and diabetes susceptibility.materials and methods: we assessed the associationbetween the insulin gene vntr genotypes,early growth and glucose and insulin metabolismin adult life in 488 subjects participating inthe helsinki birth cohort study.results: body size at birth did not differ significantlybetween the ins vntr genotypes. oneadditional type iii allele was associated with a13 g decrease (95% ci -55 to 81 g; p=o.7) in birthweight. fasting glucose concentration was highestin the carriers of the iii/ill genotype. thecumulative incidence of type 2 diabetes did notdiffer between the genotypes. interactions betweenbirth size and insulin vntr genotype inrelation to fasting glucose (p for interaction =0.08 for birth weight, p=0.05 for birth length) and2-hour insulin (p for interaction =0.04) were ob-served.conclusions: these interactions between bodysize at birth and genotype reflect interactions betweenthe insulin vntr gene and the intrauterineenvironment. our findings are consistentwith the hypothesis of developmental plasticity,where one genotype can give rise to differentphenotypes dependent on the early environment.