Overlapping genes: Several chromosomal changes can lead to either autism or schizophrenia, including, potentially, the newly identified 7q36.3 region.

A neurotransmitter called VIPR2, or vasoactive intestinal peptide receptor, is a candidate gene for schizophrenia and, potentially autism, according to a study published in February in Nature.

Several large copy number variations, or CNVs — duplications or deletions of DNA regions — are associated with both schizophrenia and autism, and are believed to contribute to a small, but significant, percentage of people with the disorders.

The new study added small overlapping duplications in the 7q36.3 chromosomal region to the list of those implicated in schizophrenia. It also identified small duplications within 7q36.3 in 3 of 1,110 individuals who have autism. Those results are not statistically significant, but suggest the region should be studied further.

Researchers identified 114 potential CNVs in 802 people with schizophrenia that are absent in 742 controls. They linked four of these, including 7q36.3, to schizophrenia in another 7,488 individuals who have the disorder. Of those four, three regions — deletions in 15q13.3, duplications in 16p11.2 and deletions in 22q11.2 — have well-described associations with schizophrenia.

Each of 29 duplications identified in 7q36.3 in people with autism overlaps with, or near, VIPR2, and four individuals have a triple duplication within this gene, the study found. These four people also show higher levels of VIPR2 in their blood, and metabolic changes — higher signaling of the chemical messenger cyclic adenosine monophosphate — related to VIPR2 function.

Drugs targeting VIPR2 could be promising treatments for schizophrenia, the researchers suggest.