Lack of association between acetylcholine receptor ϵ polymorphisms and early-onset myasthenia gravis

A patient with mutations in the acetylcholine receptor (AChR) ϵ subunit, who subsequently developed autoimmune myasthenia gravis (MG), led us to search for ϵ AChR mutations and polymorphisms in 167 patients with early-onset MG. No ϵ-subunit mutations or increased incidence of exonic ϵ-subunit polymorphisms were found. The allelic frequency of the intron polymorphism IVS11+ 20del20 was more prevalent in non–United Kingdom subjects, both patients and healthy individuals, than in United Kingdom subjects (15.8 vs. 6.2%, P = 0.0008) but not between MG patients and healthy individuals. These data provide no evidence that heteroallelic mutations or polymorphisms in the AChR ϵ subunit are involved in the development of autoimmune early-onset MG but raise issues for future studies. Muscle Nerve 29: 436–439, 2004