Dopamine gene ups schizophrenia risk.The chances of developing schizophrenia rise substantially for the small number of children who possess only one copy of a gene variant that regulates a crucial chemical messenger in the brain, according to a new finding of a long-term investigation. A team led by psychiatrist Allan L. Reiss of Stanford University School of Medicine Stanford University School of Medicine is affiliated with Stanford University and is located at Stanford University Medical Center in Stanford, California, adjacent to Palo Alto and Menlo Park. studied 24 children missing a small piece of DNA DNA: see nucleic acid. DNA or deoxyribonucleic acid One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. on chromosome 22. About 30 percent of youngsters with this deletion, which occurs in 1 in 4,000 births, eventually develop the severe mental disorder schizophrenia or related psychotic conditions. These children are also prone to other problems, including heart defects, cleft palate, and learning disorders. Prior studies showed that people with this deletion lack one copy of the usual two copies of the COMT COMT Catechol-O-Methyltransferase COMT Certified Ophthalmic Medical Technologist gene, which triggers production of a protein that breaks down the neurotransmitter dopamine dopamine (dōp`əmēn), one of the intermediate substances in the biosynthesis of epinephrine and norepinephrine. See catecholamine. dopamine One of the catecholamines, widely distributed in the central nervous system. . The protein comes mainly in two variants with contrasting dopamine-busting power, one weak and the other strong. By young adulthood, seven of the study participants with the deletion had developed schizophrenia or another psychotic disorder, Reiss and his coworkers report in the November Nature Neuroscience. Of that number, the four individuals with the weak COMT variant--who presumably pre·sum·a·ble adj. That can be presumed or taken for granted; reasonable as a supposition: presumable causes of the disaster. grew up with excessive amounts of dopamine in their brains--displayed larger drops in verbal intelligence and language skills, and harsher psychotic symptoms, than their three peers with the strong variant did. Also, the prefrontal prefrontal /pre·fron·tal/ (-fron´t'l) situated in the anterior part of the frontal lobe or region. pre·fron·tal adj. 1. brain area of the four participants with the weak variant shrank more than did that area in three participants with the strong variant. This brain region is linked to schizophrenia. COMT-associated dopamine drenching drenching farmer's term for the administration of medicines as solutions or suspensions in water by mouth with a drench bottle, gun or funnel. drenching bit to be included in a bridle as a bit. of children's growing brains creates a strong susceptibility to schizophrenia, Reiss proposes. He also hypothesizes that a dopamine drought in children who inherit a single copy of the strong COMT variant can also foster psychotic symptoms.--B.B. A selection of new and notable books of scientific interest |
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