Di-nucleotide repeat polymorphisms of the insulin-like growth factor-1 gene and their association with IGF-1, insulin-like growth factor-binding protein-1 and birth size in a Sri-Lankan cohort.

Insulin-like growth factor (IGF)-I is implicated in fetal growth. Ethnic variations of IGF-1 have also been suggested. Di-nucleotide repeat polymorphisms of the IGF-1 gene or their association with IGF-1 levels and birth size have not been studied in Sri Lankans. To describe IGF-1 di-nucleotide repeat polymorphisms and their association with IGF-1 and IGF-binding protein (IGFBP)-1 levels and birth size in a cohort of Sri Lankans. A cross-sectional study on 200 mother-newborn pairs was carried out. Maternal and cord blood levels of IGF-1 and IGFBP-1 were measured by enzyme-linked immunosorbent assay. Three di-nucleotide repeat polymorphisms of the IGF-1 gene [cytosine-adenine (CA) repeats in the promoter and 3' regions and intron 2 cytosine-thymine (CT) repeat] were studied using PCR amplification and fragment analysis. Cord blood IGFBP-1 levels correlated negatively with birth weight (p < 0.01) and crown-heel length (p < 0.05). Wild-type alleles of the CA repeat polymorphisms differed from those reported in other populations. Newborn and maternal intron 2 CT repeat polymorphism showed a significant effect on birth weight (p < 0.01 and p < 0.001, respectively), crown-heel length (p < 0.01) and head circumference (p < 0.01 and p < 0.05, respectively). Promoter region CA repeat polymorphism and intron 2 CT repeat polymorphism in the newborns were significantly (p < 0.05) associated with cord blood IGF-1 levels. Almost all these effects were limited to primiparous pregnancies. In Sri Lankans intron 2 CT repeat polymorphism of the IGF-1 gene appears to be a significant contributor to IGF-1 levels and birth size in primiparous pregnancies.

Jayanthiny P ，Tennekoon KH ，Karunanayake EH ，Kumarasiri JM ，Wijesundera AP ... -  《-》

The relationship in Japanese infants between a genetic polymorphism in the promoter region of the insulin-like growth factor I gene and the plasma level.

Kinoshita Y ，Kizaki Z ，Ishihara Y ，Nakajima H ，Adachi S ，Kosaka K ，Kinugasa A ，Sugimoto T ... -  《-》

Inverse changes in fetal insulin-like growth factor (IGF)-1 and IGF binding protein-1 in association with higher birth weight in maternal diabetes.

Lindsay RS ，Westgate JA ，Beattie J ，Pattison NS ，Gamble G ，Mildenhall LF ，Breier BH ，Johnstone FD ... -  《CLINICAL ENDOCRINOLOGY》

Influence of polymorphisms in genes encoding for insulin-like growth factor (IGF)-I, insulin, and IGF-binding protein (IGFBP)-3 on IGF-I, IGF-II, and IGFBP-3 levels in umbilical cord plasma.

In postnatal life, polymorphisms in the promoter region of IGFBP3 were associated with insulin-like growth factor binding protein (IGFBP)-3 plasma levels. Whether these associations exist in utero has not been studied yet. Polymorphisms in the IGF1 promoter (polymorphic CA-repeat) and the insulin gene variable number tandem repeats locus (INS VNTR) are further polymorphisms of interest, because associations with birth weight have been reported. We aimed to investigate associations between polymorphisms in the promoter regions of IGF1 (wild type 192 bp), IGFBP3 (rs2854744; rs13241830), and INS VNTR (rs689) with cord plasma levels of IGF-I, IGF-II, and IGFBP-3. We measured IGF-I, IGF-II, and IGFBP-3 concentrations in cord blood from 677 neonates and genotyped the selected polymorphisms. Carriers of the minor allele of both polymorphisms in the IGFBP3 gene had, on average, 4-5% lower IGFBP-3 levels per copy of the respective minor allele (p = 0.002 and p = 0.028) when compared to wild type carriers. The IGF1 promoter and the INS VNTR polymorphisms were not associated with IGF-I, IGF-II, or IGFBP-3 levels. Our data show associations of cord plasma IGFBP-3 levels and the IGFBP3 gene variants but not of IGF1 promoter and INS VNTR polymorphisms with IGF-I, IGF-II, or IGFBP-3 levels in utero.

Landmann E ，Kollerits B ，Kreuder JG ，Blum WF ，Kronenberg F ，Rudloff S ... -  《-》

Association of CA repeat polymorphism at intron 1 of insulin-like growth factor (IGF-I) gene with circulating IGF-I concentration, growth, and fatness in swine.

Estany J ，Tor M ，Villalba D ，Bosch L ，Gallardo D ，Jiménez N ，Altet L ，Noguera JL ，Reixach J ，Amills M ，Sánchez A ... -  《-》