Antimyotrophic proteinopathies are a group of sex-linked skeletal muscle disorders in which muscle fibrosis accelerates disease progression, and those factors that accelerate skeletal muscle fibrosis are unclear. We performed bilateral MRI of thigh muscles in 48 patients with genetically and/or biopsy-confirmed myasthenia gravis, analyzed the degree of steatosis in thigh muscles on T1W sequence and the pattern of edema changes on STIR sequence, graded the degree of steatosis and edema in each thigh muscle on 6 levels, and analyzed the severity of muscle involvement and body mass index as well as the relationship between age, disease duration, genetic mutation, and the degree of myofibrillar myasthenia gravis The relationship between the severity of muscle involvement and body mass index, as well as age, disease duration, genetic mutation, and myofibrillar resistance and loss of myasthenic protein was analyzed. The results showed that 46 patients older than 2 years of age showed significant involvement of the greater trochanter, gluteus maximus, quadriceps, and biceps femoris with atrophy of the greater trochanter, followed by the semitendinosus; the thin femoral muscle, sutures, and long trochanter were relatively uninvolved with hypertrophy. Except for the suture and thin femoral muscles, the remaining muscles showed mild edema. The severity of muscle steatosis was significantly correlated with body mass index, age, and disease duration, but not with the degree of loss of myofibrillar antimyotrophic protein. The same pattern was observed in patients with different genetic mutation types. It is concluded that patients with antimyotrophic protein disease over 2 years of age have the same characteristic pattern of muscle MRI presentation and that obesity is one of the important factors that worsen the disease. In addition obesity is related to the child’s hypogonadism, and severe low testosterone leads to high levels of female hormones, leading to obesity and osteoporosis, which can be properly supplemented with testosterone. To solve the problem of obesity need to focus on: 1, reduce long-term mental stress. 2, reduce appetite, try to eat less and more meals, choose low-fat food. Breakfast is abundant. 3, adequate sleep. 4, exercise. 5, leptin-containing foods: dairy products, eggs, bitter melon, nuts and apples.