Myasthenia gravis in one monozygotic twin

Abstract

The case of a 6-year-old Negro boy with myasthenia gravis is described. He had a normal monozygotic twin in whom latent myasthenia could not be demonstrated by the curare provocation test. The implications of this example of discordance for heredity as an etiologic factor in myasthenia gravis are mentioned. Examples are cited of myasthenia in familial aggregates, where heredity might have played a part, but information in these reports is too incomplete to permit generalization about genetic mechanisms. No environmental factor was uncovered to explain the development of myasthenia in only one of the twins.