 Studies using chromosomal microarray for diagnosis indicate that at least 0.5% of cases of ASD can be explained by mutations or deletions in the "SHANK3" gene.In addition, when ASD is associated with ID, "SHANK3" mutations or deletions have been found in up to 2% of individuals.The first case of PMS was described in 1985 by Watt et al., who described a 14-year-old boy with severe intellectual disability, mild dysmorphic features and absent speech, which was associated with terminal loss of the distal arm of chromosome 22.