Capillary dilation ataxia syndrome is a rare, complex and poorly prognosed neurocutaneous syndrome, also known as capillary dilation ataxia syndrome, ataxia capillaris, dyskinesia capillaris, and Lovis-Bar syndrome group. The disease is an autosomal recessive disorder and the majority of cases are disseminated. Clinical features include cerebellar ataxia with infantile onset, conjunctival capillaries, recurrent paranasal sinus and pulmonary infections, predisposition to malignancy, and mixed immunodeficiency. The pathogenesis of capillary dilation ataxia syndrome is unclear. It is an autosomal recessive disorder in which the parents do not develop the disease, but the same generation develops the disease and both sexes have equal chances of being affected. The disease may be associated with autoimmunity, abnormal tissue differentiation, and defects in DNA synthesis and repair. The neurological symptoms of the disease are mainly cerebellar ataxia, which appears in infancy and mainly affects the trunk and head. The child learns to walk with a wobbly gait and wide separation of the legs, followed by intentional tremor of the upper limbs and a positive closed-eye difficult-to-stand sign; the walking age of the child is delayed, the tendon reflex is weakened or disappears, the plantar reflex is flexion, and most children can be accompanied by choreiform movements or hand and foot In some children, there is pseudokinetic nerve palsy and compensatory movements such as head tilting and neck turning and eye blinking when looking at the target. In adults, distal limb muscle atrophy, weakness and muscle bundle tremors may appear. The first site is the exposed part of the conjunctiva of the eye similar to conjunctivitis, which gradually disappears near the cornea, and later appears in the eyelids, nose, cheeks, outer ears, neck, elbow fossa and N fossa, which are often exposed or easily stimulated. In addition, chronic seborrheic blepharitis and seborrheic dermatitis are also common. 3. Other manifestations Patients often have low humoral and cellular immune function, especially lack of secretory IgA, and are prone to recurrent respiratory infections, such as paranasal sinusitis, bronchitis and pneumonia, and also otitis media. Repeated pulmonary infections can cause extensive fibrosis of the lungs, pestle fingers (toes) and pulmonary insufficiency. Almost all children have sexual dysfunction and do not develop secondary sexual characteristics. Posterior scoliosis may occur in the late stages of the disease due to restricted movement. Patients are prone to malignant tumors, mainly malignant lymphoma and lymphocytic leukemia. Loss of appetite may occur as a result of liver involvement. Complications A variety of signs and symptoms may occur. Progressive cerebellar ataxia may be complicated by gaze nystagmus, strabismus, oculomotor difficulties, pseudomask appearance, slurred speech, and mental retardation; patients with recurrent respiratory infections are prone to B-cell lymphoma, leukemia, breast cancer, and endocrine diseases, and often die from chronic infections and tumors. Treatment For respiratory infections, effective antibiotics are given to control the infection. Immunoglobulin therapy can prevent infection and is beneficial for enhancing the immune function of the body, and drugs such as thymosin transfer factor can be used with uncertain effect. Levamisole can improve the lymphocyte conversion rate of patients with this disease. Bone marrow transplantation and thymus transplantation are still in the experimental stage. Diazepam (Valium) can reduce involuntary movements, phenothiazines can relieve chorea-like movements, and vitamin E treatment can be given to patients with intermediate to advanced disease.