Loss of Imprinting of IGF2 Gene in the Chorionic Tissues of Spontaneously Eliminated Human Embryos.

Insulin-like growth factor-2 (IGF-2) is a mitogen, growth and differentiation modulator for many cell types. It is mainly expressed during the prenatal development, and its activity strongly depends on the genomic imprinting. Genomic imprinting in the chorionic tissues of spontaneously eliminated human embryos has been studied on the model of 820-AG (Apa1) of the IGF-2 gene locus. Molecular and genetic analysis was performed on the polymorphic 820-AG IGF2 locus in 107 samples of DNA extracted from the chorionic tissues of spontaneously eliminated human embryos within 5-10 weeks of gestation. Presence of AG genotype Apa1 single nucleotide polymorphisms of the IGF-2 was shown to cause more than a 7-fold increase in the risk of embryo elimination. Thus, the loss of genomic imprinting of the IGF-2 gene may be an important cause of the miscarriages in human.