Poor esophageal motility, dilatation and barium retention in the pyriform fossa are digestive symptoms of dermatomyositis and polymyositis, which are currently considered to be autoimmune diseases. What are the causes of poor peristaltic dilatation and barium retention in the pyriform fossa? Genetic: Although familial onset of DM/PM has been reported, it is more often non-familial. HLA-B7 is elevated in myositis of Japanese ethnicity, HLA-A24 and HLA-B52 are significantly lower in PM than in DM, while CW3 is significantly higher than in DM; the HLA-DRB1*08 allele is significantly elevated in all myositis patients, especially in PM and DM, while HLA-DQA1*0501 and HLA-1DQB1*0301 are significantly lower. In Caucasians, HLA-B8 was more frequent in adult PM and JDM; HLA-DR3 was strongly correlated with anti-Jo-1 antibodies and interstitial pneumonia. HLA-DQA1*0501 has also been reported as a risk gene for JDM. C4 null gene is highly associated with JDM. New reports on genetics continue to be made, but no satisfactory results have been obtained. Metabolism: Abnormalities in collagen metabolism are associated with the development of DM/PM. For example, the carboxyterminal propeptide of type Ⅰ procollagen (PICP) was found to be significantly elevated in DM serum, and the level of PICP was positively correlated with the level of creatine (CK), while the aminoterminal propeptide of type Ⅰ procollagen (aminoterminal The level of metalloproteinases-1 (TIMP-1) was also significantly elevated; the changes in serum PICP and TIMP levels may help to evaluate the activity and severity of DM disease. Changes in mitochondrial biochemical function of skeletal muscle cells may also be related to the occurrence of DM/PM. For example, in a paired study between normal and DM patients of the same age and sex, it was observed that the levels of skeletal muscle cytochrome C oxidase-negative fibers and succinate dehydrogenase hyperreactive fibers were significantly elevated in DM; whereas the oxidation rates of different enzymatic actors and the activities of electron transport chains and ATPases did not differ between DM and normal subjects. A small number of patients had high titers of anti-mitochondrial antibodies in the serum, and mitochondrial damage was found in biopsied muscle tissue. Pediatric Wegener’s granulomatosis: It is a systemic disease characterized by necrotizing, granulomatous vasculitis of the upper and lower respiratory tract, glomerulonephritis and vasculitis of other organs. The lesions involve small arteries, veins and capillaries. Clinical manifestations often include nasal and sinusitis, pulmonary lesions, and progressive renal failure. It was once thought to be a variant of polyarteritis nodosa. Discoid lupus erythematosus: a chronic relapsing disease that primarily affects the skin and is characterized by well-defined red plaques (erythema), follicular embolism, scaling, capillary dilation, and skin atrophy. The etiology is unclear. It is more common in women, with the highest incidence around 30 years of age. The disease can be divided into two types: (1) limited skin lesions limited to the skin above the neck, and (2) disseminated lesions involving a wide range of skin areas throughout the body. Some authors believe that the disseminated form is susceptible to transformation into SLE.