A 20-year-old woman from a consanguineous Moroccan marriage, with progressive muscle weakness noted from 2 years of age and evaluated at the University of Bonn, Germany, was found to have congenital myasthenic syndrome (CMS) due to homozygosity of the 1293insG e-acetylcholine receptor subunit mutation. Compared to the original case report of a CMS with end-plate acetylcholine receptor deficiency, heteroallelic for two e-AChR subunit mutations, and affected with mild muscle weakness, in this homozygous case, the weakness was profound and was associated with muscle wasting. 
COMMENT. Differences in the acetylcholine receptor mutation haplotype can markedly influence the severity of congenital myasthenic syndrome. This profoundly affected patient is wheel-chair bound, and has almost complete external ophthalmoplegia and progressive kyphoscoliosis. Therapy with 60 to 120 mg of pyridostigmine daily was of limited benefit.