Objective: Altered methylation patterns of insulin-like growth factor (IGF)-axis genes in small for gestational age (SGA) have been reported in different populations. In the present study, we analyzed the methylation status of IGF-axis genes in the placenta of appropriate for gestational age (AGA) and SGA neonates of South Indian women.
Methods: Placental samples were collected from AGA (n = 40) and SAG (n = 40) neonates. The methylation of IGF-axis genes promoter was analyzed using MS-PCR.
Results: IGF2, H19, IGF1, and IGFR1 genes promoter methylation was 2.5, 1.5, 5, and 7.5% lower in SGA compared to AGA, respectively. Co-methylation of IGF-axis genes promoter was 40% and 20% in AGA and SGA, respectively. IGF-axis gene promoter methylation significantly (p < 0.05) influenced the levels of IGFBP3 protein, birth weight, mitotic index, gestational weeks, and IGFR1 and IGFR2 gene expression.
Conclusion: IGF-axis genes methylation was lower in SGA than in AGA, and the methylation significantly influenced the IGF-axis components.
Keywords: IGF-axis; appropriate for gestational age; methylation of genes; placental tissue; small for gestational age.