SERUM CHOLINESTERASE (PSEUDOCHOLINESTERASE) IN DOWN'S SYNDROME: l. PHENOTYPE FREQUENCIES AT THE E1 AND E2 LOCI.

This article determines serum cholinesterase phenotypes in a person with Down's syndrome. Dibucaine, fluoride and RO2-0683 inhibition studies were used to determine the serum cholinesterase phenotypes in a sample of 130 subjects with Down's syndrome and fifty-three mentally retarded control subjects. The means and distribution of the dibucaine, fluoride and RO numbers in both groups were similar to those reported in normal subjects. The presence of the additional G-group chromosome in Down's syndrome has suggested to several investigators the possibility of altered protein metabolism.