THURSDAY, Dec. 24 (HealthDay News) -- Scientists who identified gene mutations that influence human brain size say their findings may help explain differences in brain size in healthy people and those with neurological and psychiatric disorders.
The variations occur in genes associated with microcephaly, a neuro-developmental disorder in which brain size is dramatically reduced. These mutations can reduce brain size by about two-thirds.
The microcephaly genes are believed to have played a role in the evolutionary expansion of the human brain, and four of the genes have evolved rapidly and been subjected to strong selective pressure in recent human evolution, said the American and Norwegian scientists.
"It is obvious that such anatomical changes must have a basis in genetic alterations. Until now, little has been known about the molecular processes involved in this evolution and their genetic underpinnings. Now we have a piece of that genetic puzzle," Lars M. Rimol, a research fellow at the University of Oslo, said in a news release.
The study was published in this week's online issue of the Proceedings of the National Academy of Sciences.
Zero to Three has more about brain development.
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