Associations between birth and one year anthropometric measurements and IGF2 and IGF2R genetic variants in African American and Caucasian American infants.

Insulin-like growth factor 2 receptor (IGF2R) and insulin-like growth factor 2 (IGF2) genetic variants have been inconsistently associated with low birth weight and birth length in Caucasian and Asian infants, however few studies have included African Americans (AA). Generalized linear models and logistic regression models were used to examine associations between IGF2R single nucleotide polymorphisms (SNP) rs629849 and rs8191754, and IGF2 SNP rs680 and infant anthropometric measurements, in a racially diverse birth cohort in Durham County, North Carolina. Caucasian American (CA) carriers of the IGF2R SNP rs629849 were heavier (P = 0.02) and longer (P = 0.003) at birth, however body size at age 1 yr was similar to that of AA. Birth length significantly differed between carriers and non-carriers of the IGF2 rs680 variant in both AA (P = 0.04) and CA infants (P = 0.03). Both AA and CA carriers were 1 cm shorter at birth compared to non-carriers. We found no evidence for an association between rs8191754 and infant anthropometric measurements. Associations between SNPs andone year weight gain were only observed for rs680; CA infant carriers of rs680 variants weighed less than non-carriers at year one (P = 0.03); however, no associations were found in AA infants at year one. Larger studies using ancestral markers are required to disentangle these associations.