title: Twin study of Parkinson disease.
abstract: Zero concordance for Parkinson disease was found in the first 12 monozygotic twin pairs examined in an ongoing twin study. One co-twin (subject without Parkinson disease) had essential tremor, another had cerebral vascular disease, and a third was an alcoholic. Cigarette smoking appeared to be less frequent in the probands than in the co-twins (11.9 versus 16.1 pack-years). There was also evidence of premorbid personality differences between probands and co-twins dating back to late adolescence or early adult years. These preliminary findings suggest that genetic factors do not play a major role in the etiology of Parkinson disease and point to a prodromal onset of the disease as early as late adolescence or early adult life.
mesh_terms: D000368:Aged; D000437:Alcoholism / Q000150:complications; D004200:Diseases in Twins; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000235:genetics* / Q000523:psychology; D010551:Personality; D011247:Pregnancy; D012907:Smoking; D014430:Twins, Monozygotic