IGF1 Promoter Polymorphism and Cranial Growth in Individuals Born Very Preterm

Background: Major defects in the IGF1 gene are associated with severely reduced cranial and linear growth. The association between IGF1 promoter polymorphisms and growth is uncertain. Aims: To test the effect of the IGF1 192-bp allele on cranial and linear growth and body mass index (BMI) from birth until age 5 years, and on IQ and serum IGF-1 at age 19 years. Methods: In a birth cohort, including 285 individuals born at a gestational age <32 weeks from the Project On Preterm and Small-for-gestational age infants (POPS), cohort anthropometric measurements were analyzed. At age 19 years IGF1 genotype, serum IGF-1 level and IQ were determined. Regression analyses were performed with mixed models. Results: Homozygotes for the 192-bp allele had a slower cranial growth from birth until age 5 years, and a tendency towards less brain sparing and a slower linear growth compared to the other 2 genotype groups. IGF1 genotype was not associated with IQ or BMI development. Head circumference SDS at age 5 years was positively associated with IQ at age 19 years. Conclusion: Homozygosity for the IGF1 192-bp allele is associated with a slower cranial growth from birth until age 5 years in individuals born very preterm. Copyright (C) 2011 S. Karger AG, Basel