Seybold_1981_Neurology_31_778

Antibodies to acetylcholine receptors (AChR-ab) were detected in a patient with myasthenia gravis (MG) and at much lower levels in her asymptomatic fraternal twin and one other asymptomatic sibling. These three carried the HLA-B8 allele, as did four other family members. In a previous study, we observed no AChR-ab in 175 non-MG patients. The occurrence of AChR-ab in 3 of 12 siblings suggests that all were affected by an unidentified pathologic factor acting on a favorable genetic background.