Gly(247)-->Asp proenkephalin A mutation is rare in schizophrenia populations

Schizophrenia is a complex and severe disorder of unknown cause and pathophysiology. In previous work examining an opioid hypothesis for schizophrenia, we identified a missense mutation (Gly(247)-->Asp) in the proenkephalin A gene of one African-American patient. In the current study involving an extended set of African-American and other patients, we sought to identify additional mutant alleles and to determine the distribution of these alleles among several racial groups. However, the Gly(247)-->Asp allele was not detected in any of 116 African-American (67 cases, 49 controls), 659 Caucasian, 1 Hispanic, 4 Asian, and 7 Native American individuals. Therefore, it appears that this mutation is a rare event of unknown clinical significance.