Reduced Monoamine Oxidase Activity in Platelets: A Possible Genetic Marker for Vulnerability to Schizophrenia

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Science  02 Mar 1973:
Vol. 179, Issue 4076, pp. 916-918
DOI: 10.1126/science.179.4076.916


Monoamine oxidase activity in blood platelets was measured, with [14C]tryptamine as substrate, in 13 monozygotic twin pairs discordant for schizophrenia and in 23 normal volunteers. The monoamine oxidase activity of both schizophrenic and nonschizophrenic co-twins was significantly lower than it was for the normals, and it was highly correlated between twins. In addition, there was a significant inverse correlation between a measure of the degree of the schizophrenic disorder and the monoamine oxidase activity. These data suggest, but do not prove, that reduced platelet monoamine oxidase activity may provide a genetic marker for vulnerability to schizophrenia.