TTN-related hereditary myopathy with early respiratory failure presented with elevated hemoglobin initially: A case report and literature review
Hanyang Liang,
Dong Liu,
Qian Gao,
Zhenguo Zhai
Affiliations
Hanyang Liang
Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, National Center for Respiratory Medicine Institute of Respiratory Medicine, Chinese Academy of Medical Sciences National Clinical Research Center for Respiratory Diseases, Beijing 100029, China; State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
Dong Liu
Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, National Center for Respiratory Medicine Institute of Respiratory Medicine, Chinese Academy of Medical Sciences National Clinical Research Center for Respiratory Diseases, Beijing 100029, China; Peking University China-Japan Friendship School of Clinical Medicine, Beijing 100029, China
Qian Gao
Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, National Center for Respiratory Medicine Institute of Respiratory Medicine, Chinese Academy of Medical Sciences National Clinical Research Center for Respiratory Diseases, Beijing 100029, China; Corresponding author. No 2, East Yinghua Road, Chaoyang District, Beijing 100029, China.
Zhenguo Zhai
Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, National Center for Respiratory Medicine Institute of Respiratory Medicine, Chinese Academy of Medical Sciences National Clinical Research Center for Respiratory Diseases, Beijing 100029, China; Peking University China-Japan Friendship School of Clinical Medicine, Beijing 100029, China
Background: As common abnormal conditions in clinical practice, hypoxemia and respiratory failure are mainly caused by various respiratory diseases. However, other causes are easily overlooked but deserve more attention from doctors. Case presentation: A 44-year-old man presented with dyspnea for 10 years. In the early stage, his dyspnea was mild without hypoxemia, and he was misdiagnosed with polycythemia vera due to elevated hemoglobin level. He later developed to respiratory failure but he did not have weakness in his extremities. The positional difference in pulmonary function tests and arterial blood gas analysis led us to identify the respiratory muscle dysfunction. Fatty infiltration of the thigh muscle found by magnetic resonance imaging and muscle biopsies gave us more clues to the causes of diaphragmatic dysfunction. Finally, in combination with his family history and the results of whole exome sequencing, he was diagnosed with hereditary myopathy with early respiratory failure (HMERF, OMIM 603689) caused by a variant in the titin gene (TTN). Conclusions: We have identified a Chinese family with HMERF due to genetic variants in TTN NM_001256850.1: c.90272C > T, p. Pro30091Leu, located at g.179410829A > G on chromosome 2 (GRCh37), which may be specifically associated with the diagrammatic dysfunction. And hyperhemoglobinemia could serve as a potential sign for the early identification of HMERF.
