Chapter 36 - Imprinting Disorders in Humans

Abstract

This chapter discusses the imprinting disorders in humans. The most prominent imprinting disorders (IDs) are Prader–Willi and Angelman syndromes (PWS, AS). Human genes are believed to be imprinted by epigenetic mechanisms that allow expression from only one of the two paternal alleles. These parental imprints undergo a cycle during the life of an organism that allows their reprogramming at each generation. The imprinted marks are inherited from the parental gametes and are then maintained and realized in the somatic cells of an individual. The balanced expression of imprinted genes is needed for the regular development of an individual, and it is therefore not surprising that many imprinted genes are involved in human growth. There are a growing number of conditions where genomic imprinting effects are recognized to be associated with clinical disorders. Based on the observation that growth disturbance and behavior abnormalities are common features of IDs, genomic imprinting should be suspected in any disorder of unknown etiology characterized by the clinical signs. Disorders with an unusual pattern of inheritance should be studied for the possibility that genomically-imprinted genes are involved.