Abstract: In the past few fears, there has been a nascent convergence of scientific understanding of human disease with epigenetic. Identified epigenetic processes involved in human disease include chromatin remodeling, genomic imprinting, X chromosome inactivation, and noncoding RNAs regulation. These processes influence chromatin structure and thereby regulate gene expression on the chromosome level or a cluster of linked genes level. Deregulation of these processes result in lots of disease which are characterized by complex patterns of mutations and associated phenotypes affecting pre- and postnatal growth, development, and neurological function. Epigenetic diseases are illustrated by the array of multi-system disorders and neoplasias and investigations of these diseases have an impact on biomedical research and provide interesting models for functions and mechanisms of epigenetic gene control.