RELEVANCE OF GENOMIC IMPRINTING IN INTRAUTERINE HUMAN GROWTH

Expression of imprinted genes IGF2, PHLDA2, CDKN1C and KCNQ1 in fetal growth restriction. Purpose: Relation of imprinted genes (IGF2, CDKN1C, PHLDA2 and KCNQ1) with human fetal growth. Methods: RNA was extracted from fetuses with growth restriction and from the control group without growth restriction. cDNA synthesis was performed to evaluate the gene expressions patterns of IGF2, CDKN1C, PHLDA2, H19 and KCNQ1 genes using RT-PCR. The housekeeping gene GAPDH was used as control. DNA extraction and MS-MLPA were also performed to assess the IC1 and IC2 DNA methylation status on chromosome 11p15.5. Results: The expression levels of IGF2 in the growth restriction group were statistically down-regulated (p < 0.0001). Sixty five percent of the cases with IUGR were hypomethylated in IC1. Conclusions: The genomic imprinting is a phenomenon that plays a very important role in the fetal and placental development. Several imprinting genes may regulate this process and despite the several studies performed before additional research is still required. This study allows us to stress the importance of IGF2 gene during the pregnancy. Hypomethylation of the IC1 on chromosome 15p15.5 and down-regulation of the IGF2 gene seems to be associated with intrauterine growth restriction