Familial autoimmune myasthenia gravis.

We describe a family with parental consanguinity and five of 10 siblings affected by late-onset autoimmune myasthenia gravis. We propose a genetic mechanism as a predisposing factor in this family. Our analysis excludes the major histocompatibility complex, the beta subunit of the acetylcholine receptor, and the T-cell receptor alpha and beta subunits as candidate genes for the disorder in this family.