SILENT CHOLINESTERASE GENE IN AN ASIAN INDIAN FAMILY IN TRINIDAD

Cholinesterase activity was estimated in the serum of a Trinidadian fe male of Asian Indian descent. Her serum cholinesterase was pathologica lly low (0.17 U/ml) compared to the average reported for the populatio n (10.59 +/- 2.77 U/ml), and her dibucaine number could not be estimat ed. In a pedigree study her sister displayed similar enzyme activity a nd cholinesterase was 0.09 U/ml. Cholinesterase could not be detected in the sera of both sisters using electrophoresis. Among three generat ions of the family studied, the silent variant of the cholinesterase g ene could be segregated in offspring of the maternal uncle (normal cho linesterase phenotype) whose spouse's serum displayed an intermediate dibucaine number. The possible inheritance of the silent gene in the p edigree is discussed.