Imprinting

Imprinting and ASD

Less than 1% in the entire mammalian genome is imprinted, but many of these imprinted genes are extremely important physiologically. Most mammalian cells express both maternal and paternal inherited alleles for a particular gene, but certain cell regions only express one of these alleles. Such genes where only one allele is expressed are known as Imprinted genes. Additionally, some genes show biallelic expression in certain cell populations and monoallelic expression in others.¹ UBE3A is one imprinted gene that has been implicated in ASD.²

In imprinting, one of the alleles (either the mother's or the father's) is ALWAYS silenced in a particular cell region. Changes in imprinted genes then could account for the large number of males affected. ¹