A family with an MYH9-related disorder with different phenotypes masquerading as immune thrombocytopaenia: an underrepor
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CASE REPORT
A family with an MYH9‑related disorder with different phenotypes masquerading as immune thrombocytopaenia: an underreported disorder in Taiwan Ying‑Chih Huang1 · Yu‑Hung Shih2 · Ching‑Yeh Lin2 · Ping‑Fang Chiu2 · Su‑Feng Kuo3 · Jen‑Shiou Lin3 · Ming‑Ching Shen2,4 Received: 8 April 2020 / Revised: 3 July 2020 / Accepted: 14 July 2020 © Japanese Society of Hematology 2020
Abstract A 66-year-old woman had experienced abnormal bleeding since the age of 7. Thrombocytopenia was not detected until she was 48, and immune thrombocytopenia was diagnosed at age 66. She also reported experiencing hearing disturbance since the age of 30 and acute renal failure since the age of 61 but reported no visual disturbance. Her younger son, who was 40 years old, also experienced abnormal bleeding since the age of 6, but immune thrombocytopenia was diagnosed as late as age 35. He had no other associated disorders. Laboratory examinations of both mother and son revealed a low platelet count (8000 and 29,000 µL, respectively), giant platelets and Döhle body-like granulocyte inclusion bodies. The mother had a high creatinine level (15.4 mg/dL) and normal liver enzyme levels. MYH9 genetic analysis identified a heterozygous mutation, c.101T>A, p.Val34Glu at exon 2 in both patients. These clinical and laboratory findings were consistent with a diagnosis of an MYH9-related disorder with different phenotypes observed in the same family. MYH9-related disorders were recognised in 2003, but were often misdiagnosed as immune thrombocytopenia, and hence, they have rarely been reported in Taiwan. Keywords Immune thrombocytopenia · May–Hegglin anomaly · MYH9 · MYH9 mutation · MYH9-related disorder
Introduction Myosin heavy chain 9 (MYH9)-related disorders (MYH9RDs) represent a group of autosomal dominant disorders characterised by macrothrombocytopaenia and Döhle bodylike cytoplasmic granulocyte inclusion bodies in all patients [1]. Over time, most patients with such hereditary disorders develop noncongenital extrahaematological manifestations, Ying-Chih Huang and Yu-Hung Shih contributed equally to this manuscript. * Ming‑Ching Shen [email protected] 1
Department of Research, Changhua Christian Hospital, No. 135, Nanxiao Street, Changhua City, Taiwan
2
Department of Internal Medicine, Changhua Christian Hospital, Changhua City, Taiwan
3
Department of Laboratory Medicine, Changhua Christian Hospital, Changhua City, Taiwan
4
Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
such as sensorineural hearing loss, presenile cataracts, and nephropathy, which often evolve into end-stage renal disease and chronic elevation in liver enzymes [2, 3]. MYH9-RDs are caused by mutations in MYH9, which is located on chromosome 22q12.3–13.1 and consists of 41 coding exons that encode the nonmuscle myosin heavy chain IIA (NMMHCIIA) [4–6], a cytoskeletal contractile protein involved in cytokinesis, phagocytosis, cell mobility and cell shape maintenance [2, 7–9]. Mutations in the MYH9 can affect other o
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