Succinylcholine sensitivity in a Nova Scotia family.

Succinylcholine apnoea is usually the result of a delay in hydrolysis of the injected muscle relaxant due to the presence of an inherited defect in the enzyme cholinesterase. This report presents a Nova Scotia family in whom several members had "difficulty in breathing" following anaesthesia. Subsequent investigations revealed the presence of several phenotypes of the enzyme cholinesterase including individuals who were homozygous for the atypical cholinesterase genes. The frequency of occurrence and significance of the various phenotypes are discussed, together with their management and recommendations for family screening.