[Impaired epigenetic gene activity regulation and human diseases].

The epigenetic (i.e. heritable states that are mediated by changes in DNA other than nucleotide sequence) mechanisms of regulation of gene expression have been recently the focus of intensive studies. Genomic imprinting refers to the epigenetic gene marking that results in monoallelic expression. The epigenetic mechanism of imprinting is based on the gamete-specific methylation of some mammalian genes, which restricts their expression on one of the parental chromosomes. The imprinted genes control fetal and placental development, cell proliferation and adult behavior. Changes in the normal imprinting patterns give rise to numerous genetic diseases, including cancer. Examining the molecular processes that mediate these methylation genome changes will give use a great insight into the mechanisms of regulation of gene activity and into the etiology of some human genetic diseases.