Birth size, postnatal growth and growth during growth hormone treatment in small-for-gestational-age children: associations with IGF1 gene polymorphisms and haplotypes?

BACKGROUND

Short small-for-gestational-age (SGA) children experience pre- and postnatal growth restriction, which might be influenced by polymorphisms in the IGF1 gene. The well-known -841(CA)(n)/192 bp polymorphism has been associated with birth size and cardiovascular disease.

AIMS

To determine whether birth size, postnatal growth and growth during growth hormone (GH) treatment, were associated with IGF1 gene polymorphisms and haplotypes.

METHODS

201 short SGA children were investigated for four IGF1 gene polymorphisms in the promoter (-G1245A, -841(CA)(n)), intron 2 (+3703(CT)(n)) and 3UTR (+A1830G). Spontaneous growth and growth during GH treatment were studied.

RESULTS

The -1245 A allele was identified as a marker-allele for the well-known -841(CA)(n)/non-192 bp allele, both part of haplotype 2. The -1245 A allele was not associated with head circumference at birth, but was associated with a postnatal 0.3 SDS smaller head circumference at age 1-3. The -1245 A allele was also associated with a 1-week shorter gestational age which explained the association with a smaller absolute birth size. No associations were found with gestational age-adjusted birth size, height and weight SDS during postnatal life and with growth during GH treatment.

CONCLUSIONS

The -G1245A SNP appeared to be a marker for the well-known -841(CA)(n)/192 bp polymorphism. Haplotype 2, of which the -1245 A allele was the marker, was associated with a smaller head circumference SDS during spontaneous postnatal growth, but not during GH treatment.