Developmental delay could stem from nicotinic recepto...( HOUSTON - (Nov. 8 2009) The loss o...)

HOUSTON - (Nov. 8, 2009) The loss of a gene through deletion of genetic material on chromosome 15 is associated with significant abnormalities in learning and behavior, said a consortium of researchers led by Baylor College of Medicine (www.bcm.edu) in a report that appears online today in the journal Nature Genetics.

"This research goes about 95 percent of the way to pinning these problems in a specific group of individuals to this gene," said Dr. Arthur L. Beaudet (http://www.bcm.edu/news/mediacenter/basic_science.cfm#beaudet), chair of molecular and human genetics at BCM. He believes that the deletion will be identified in other people with behavioral problems as well as schizophrenia, developmental delay and epilepsy. The gene's role in schizophrenia has been under study for some time.

Previously, a larger deletion containing more genes had been reported in people with the same constellation of disorders. In this work, Beaudet, Dr. Pawel Stankiewicz (http://www.bcm.edu/genetics/?pmid=11046), assistant professor of molecular and human genetics at BCM, and colleagues found that a smaller deletion of genetic material the whole of the gene in question, CHRNA7, and a part of another was associated with similar problems in 10 members of four families.

"We scanned the genome of about 10,000 people to find this rare but important defect," said Stankiewicz.

"This gene encodes a subunit of a nicotinic receptor," said Beaudet. "It is a gene that mediates the response to nicotine via a receptor whose normal ligand is acetylcholine." The gene encodes a protein called an ion channel, which allows ions to flow in and out of neurons in the brain. Defects in ion channels have previously been associated with forms of epilepsy or seizure disorder.

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