UNASSIGNED: 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).
UNASSIGNED: 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.
■一名44岁男子出现呼吸困难10年。在早期阶段,他的呼吸困难轻微,没有低氧血症,由于血红蛋白水平升高,他被误诊为真性红细胞增多症。他后来发展为呼吸衰竭,但四肢没有虚弱。肺功能检查和动脉血气分析的位置差异使我们确定了呼吸肌功能障碍。通过磁共振成像和肌肉活检发现大腿肌肉的脂肪浸润为我们提供了更多有关膈肌功能障碍原因的线索。最后,结合他的家族史和整个外显子组测序的结果,他被诊断为遗传性肌病伴早期呼吸衰竭(HMERF,OMIM603689)是由肌动蛋白基因(TTN)的变体引起的。
■我们已经确定了一个由于TTNNM_001256850.1:c.90272C>T中的遗传变异而患有HMERF的中国家庭,p.Pro30091Leu,位于2号染色体上的g.179410829A>G(GRCh37),这可能与图解功能障碍特别相关。高血红蛋白血症可以作为早期识别HMERF的潜在标志。