[Autoimmune familial myasthenia in 2 sisters with a follow-up of more than 30 years].

The clinical course of two sisters with myasthenia initially published in La Revue Neurologique in 1960 has been followed. Both had secondary severe respiratory impairment requiring a tracheotomy and mechanical ventilation. Thymectomy was performed in both and revealed residual thymic tissue. Complete remission was observed long after thymectomy even with the persistence of antiacetylcholine receptor antibodies which are still present in the older sister despite intercurrent autoimmune thyroiditis and in the younger sister despite the development of mediastinal lymphosarcoma leading to death 32 years after the onset of myasthenia.