Seronegative Myasthenia Gravis and a Biermer’s Anemia: A Rare Association

We report a rare association of seronegative myasthenia gravis and a Biermer’s anemia (or pernicious anemia). A Senegalese patient of 31 years has been followed for a vitamin B12 deficiency anemia, 12 months before his hospitalization in our department. She has been admitted for an intense and invalidating fatigability in spite of the correction of anemia, associated to a right ptosis. This clinical picture has electively been improved to the prostigmine test. The electromyography had revealed a compatible decrement with a diagnosis of myasthenia. The positivity of the antibodies anti gastric parietal cells and the twice negativity of the antibody against acetylcholine receptor (AChR) and muscle-specific kinase (MuSK) had permitted to deduct a diagnosis of seronegative myasthenia and Biermer’s anemia. The evolution was favorable under substitutive B12 vitamin therapy associated to corticotherapy and azathioprine. We insist on the research and the early treatment of a myasthenia, in a context of Biermer’s anemia, before suggestive clinical signs in spite of the negativity of the anti-Rach antibodies and anti-Musk.