Evidence for mutation being the source of the abnormal gene for plasma cholinesterase.

Results of cholinesterase, dibucaine and fluoride numbers, and scoline hydrolysis rates are presented in a family found to have normal, silent and abnormal genes for plasma cholinesterase. Five sibs, confirmed by red cell grouping and tissue typing, have been shown to possess a cholinesterase pattern which cannot be explained on the basis of accepted theories of inheritance. In view of this it is suggested that, in this family, a mutation has occurred from a normal or silent gene to an abnormal gene.