Genetic data from parents are required to identify whether variants are inherited or have arisen de novo. So far, although CNVs have been found to be both inherited and de novo in origin, much interest has focused on de novo mutations. Such mutations are associated with risk of ASD, ID, and schizophrenia but would not contribute to the familial transmission of these disorders. Increased paternal age has been found to be associated with some types of mutations, as well as with risks of both ASD and schizophrenia. Rare de novo CNVs do not, however, necessarily explain all the observed paternal age effect.
