The Val/Val variants might boost schizophrenia risk.
Those who performed poorly on visual memory recall tests were found to have two characteristics: less brain activity in the region known to regulate long-term memory, and the presence of a particular form of the BDNF gene.
The gene comes in two forms (known as "met" and "val"), and the research found that people with one or two copies of "met" had less memory recall.
The COMT gene comes in two common forms or alleles, Val and Met. As with any gene, people inherit one allele from each parent. Participants with the Val/Val version of the COMT gene performed worse on the card-sorting test than those with Val/Met or Met/Met variations. The researchers also examined transmission of the gene from 126 "heterozygous" parents (who had the Val/Met version) to their schizophrenic children. They found that 75 schizophrenics inherited the Val allele, compared to 51 who inherited the Met allele, suggesting that the Val allele increases risk slightly.
The researchers think the Val allele may compromise dopamine function in the prefrontal cortex, impairing working memory. The authors write, "Thus the COMT Val allele … might add to or interact with other causes of prefrontal malfunction in those at risk for schizophrenia and thereby increase their susceptibility."
It is possible that either Val/Val or Val/Met offer advantages in other areas. Likely that is the case or else the Val variant would have been selected out of existence.
|Share |||Randall Parker, 2002 November 09 05:41 PM Brain Genetics|