Also of interest is a 2.5 Mb rare de novo duplication on chromosome 22q11.2 which corresponds to the recurrent heterozygous deletion that results in velocardiofacial syndrome (Table 2, Figure 3C). Details regarding the clinical features of this individual were described in an earlier case report (75). There is convincing evidence for an increased rate of psychosis and ID in individuals carrying the 22q11.2 deletion (76-78). Moreover, data from multiple recent studies of de novo CNVs in this region in individuals with ASD has shown an association, but only when duplications and deletions are considered together (38). Overall, there is not sufficient data to determine whether this is justifiable, as it is not clear whether 22.q11.2 duplications are independently associated with a developmental phenotype (79-81) or represent an incidental finding. However, recent evidence with regard to the contribution of deletions and duplications at 16p11.2 to ASD and a range of other conditions suggests that duplications of the 22q11.2 locus certainly warrant further evaluation with regard to their role in the risk for a variety of developmental outcomes, including TS (38).
