Scientists suspect that a mutated Pten gene is one of the contributing factors to autism and have shown its association with macrocephaly, the abnormal development of an enlarged brain and head.

For instance, duplications within the chromosomal region 1q21 are associated with autism and macrocephaly, while deletions are linked to schizophrenia and microcephaly.

Augmentation of the volume of the head is called macrocephaly, and there are a number of curious examples related.