Corresponding Author:
Dr. Sreethish Sasi,
Medical Resident, Department of Internal Medicine
Hamad Medical Corporation
Al Rayyan Road, Doha, Qatar. PO Box: 3050
Ph: +974- 50290089
E-mail: - Ssasi7@hamad.qa Alternate Email: - sreethishsasi@gmail.com
Abstract: 1.7% of myeloproliferative neoplasms are associated
with autoimmune conditions. Association of myasthenia gravis (MG) with
chronic myeloid leukemia is reported, but its association with
polycythemia vera (PV) has never been reported. We report two
patients who had MG and PV with JAK2V617F mutation. Both had
splenomegaly but no thymoma.
Key Clinical Message: Screening for MG in patients with PV
positive for JAK2V617F mutation can help in early diagnosis and
treatment, resulting in a significant reduction in morbidity and
mortality.
Keywords: Myasthenia Gravis, Polycythemia Vera,
Interferon-alpha, Paraneoplastic syndromes
Background: Myasthenia gravis (MG) is an autoimmune disease
characterized by antibodies to acetylcholine receptors at the
neuromuscular junction (NMJ). The prevalence of MG in the US is 0.02%
[1]. Prevalence in Arab countries is slightly higher (0.05% –
0.08%) [2]. It involves the extraocular muscles initially,
characterized by fluctuating muscle weakness worsening with exercise and
improving with rest. MG has an established association with autoimmune
thyroiditis, Grave’s disease, rheumatoid arthritis, systemic lupus
erythematosus (SLE), and type 1 diabetes mellitus [1].
Myeloproliferative Neoplasms (MPNs) are a group of rare blood cancers
due to stem-cell hyperplasia characterized by an increased peripheral
blood cell count, overactive bone marrow, and proliferation of mature
hematopoietic cells [3]. Chronic myeloid leukemia (CML), essential
thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis are
designated as MPNs, with CML being positive for BCR-ABL1 gene fusion
(Philadelphia chromosome) [4] and the latter three negative [5].
The majority of BCR -ABL1 negative MPNS are sporadic; however, there are
reports of familial cases from different parts of the world [6].
Paraneoplastic syndromes are clinical syndromes involving non-metastatic
systemic effects that accompany a malignant disease. Neurologic
paraneoplastic syndromes are estimated to occur in fewer than 1% of
patients with cancer [7 -9]. There have been rare documentations of
association of MG with CML [8, 9]. However, the association of MG
and PV has never been reported in the literature up to our knowledge.