Myosin myopathies consist of a set of inherited diseases caused by mutations in myosin heavy chain (MyHC) genes. Among them, MYH2 mutations have been reported to lead myopathy with ophthalmoplegia, mild to moderate muscle weakness characterized by lack of type 2A muscle fibers. To date, there is still no specific treatment for MYH2 mutated patients.

A 35-month-old girl was admitted for her motor developmental disorder associated with intellectual disability. A physical examination revealed the decreased muscle strength and muscle tone of her lower limbs and facial muscles combined with poor function of sitting and standing balance. Based on the primary assessment, a general rehabilitation therapy plan for the girl was set-up, which involved balance training, muscle strength training in low extremity, walking training, gross and fine motor function training, as well as family education. However, after the first phase of training, her motor skills were only improved mildly as well as her balance function. In the meantime, whole-exome sequencing was performed, and a novel heterozygous mutation was discovered in her MYH2 gene. These two mutations were predicted to be pathogenic, which can lead to proximal myopathy and extraocular muscle paralysis, mainly involved in type 2A muscle fibers. After her accurate diagnosis, active exercise and endurance exercise were added in addition to original rehabilitation training program and aim to shift the expression of myosin heavy chain isoform from fast to slow.

Twelve weeks after the optimized rehabilitation training, the function of her gross and fine motor was improved notably. In addition, her ability of standing, walking and jumping was enhanced significantly as well.

In this study, we described for the first time the clinical remission of myopathy with MYH2 missense mutations after effective rehabilitation. Precision medicine is incredibly helpful for patients with unexplained myopathies to develop a suitable rehabilitation program.