Genomic imprinting is an epigenetic form of regulation of gene expression. 
Imprinted genes are transcribed from one allele of specific parental origin. 
Such genes are normally involved in embryonic growth and behavioral development. 
Deregulation of imprinted genes has been observed in a number of human diseases 
as gestation trophoblastic disease, Prader-Willi, Angelmann and 
Beckwith-Wiedemann syndromes and plays significant role in the carcinogenesis. 
Review of recent knowledge on mechanism and regulation of imprinting is 
presented in this paper.