The plasma cholinesterase variants in mentally ill patients.

The distribution of the plasma cholinesterase variants found in 1,374 mentally ill patients differs from that of a random control sample. The patients are more likely to have a rare phenotype than an individual from the normal population. None of the diagnostic groups have been shown to differ in the distribution of the E1a gene, but there is strong statistical evidence that Group IV (psychosis) patients have a higher frequency of the E1f gene than the other groups. The overall frequency of the electrophoretic variant C5 + did not differ significantly from that observed in a Caucasian population, with the exception of the increase observed in Group IV c2. Twenty-eight unrelated patients with Huntington's chorea were found to have a significantly altered incidence of the C5 + variant and six patients from this group were found to have the rare E1f gene. Our results indicate that the plasma cholinesterase variants may provide some insight into the inheritance of Huntington's chorea.