PTEN and Macrocephaly: The frequency of PTEN mutations in our patient series is as high as 20.5%, one of the highest figures but still consistent with respect to data reported in the literature [19]: in fact, a great variability in the frequency of PTEN PVs in patients with ASD and macrocephaly has been reported, ranging from 1 to 22% [5], which most likely reflects the selection criteria of patients.