FROM A MISDIAGNOSIS TO DIAGNOSIS OF MYOSIN HEAVY CHAIN 9 RELATED PLATELET DISORDER

S BEK1,  N EREN1
1Kocaeli University Hospital, Kocaeli, Turkey

Background: Myosin Heavy Chain 9 (MYH9) missense mutations have been characterized by large platelets, leukocyte Döhle bodies, in variable extent sensorineural deafness, cataracts, and glomerulopathy. We report the clinical manifestations and treatment of a case with heterozygous MYH9 R702 mutation.
Case Report: A 25-year old female with triad of thrombocytopenia, sensorineural hearing loss and end stage renal disease (ESRD) presented with uremic symptoms with a history of chronic thrombocytopenia with recurrent epistaxis, gum bleeding and anemia  since childhood. She was misdiagnosed with ITP, Bernard -Soulier and Alport’s syndrome chronologically. First misdiagnosis of idiopathic thrombocytopenia was treated oral methylprednisolone, then pulses of  intravenous immunoglobulin (IVIG) and azathioprine 300 mg/day were tried  respectively with no response. The diagnosis was re-evaluated; bone marrow biopsy was done relieving increased number of megakaryocytes with moderately decreased platelet budding and increased reticulin build-up. Large platelets and Döhle bodies on peripheral blood smear were noted.  The audiogram done at the age of 22 revealed a profound  high-frequency sensorineural hearing deficit bilaterally and the renal biopsy was done with 3 gr/day proteinuria. Renal biopsy revealed features consistent with chronic glomerulosclerosis. Genetic analysis was performed at the age of 23  revealing MYH9 gen: NM_002473.5 p.R702C (c.2104C>T) heterozygous mutation. She has no findings of cataract on examination. She has been diagnosed with MHY9 Related Disease (MHY9RD) and treated with eltrombopag 75 mg/day. After a successful increase to 17 000/mm3 in platelet count, the peritoneal catheter was  implanted successfully without complications.
Conclusions: MHY9RD is a rare syndrome that can end with ESRD and severe hearing loss. This rare diagnosis should be kept in mind and treatment modalities like renal biopsy should be done with eltrombopag.


Biography:
I am an assistant professor in Kocaeli University Hospital and will be working for one-year in Sydney University, Nephrology Department as an ISN-fellow between 1st June- 2018/ 2019.

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