Widening of incisor spacing is one of the symptoms of mannosidosis type II. Mannosidosis type II mostly develops after 2 years of age with normal physical and psychomotor development, progressive brain development delay starting after 2 years of age, frequent respiratory infections, ugly face, thick eyebrows, widened incisor spacing, convex jaw, low anterior hairline, and mild bilateral deafness (mostly sensory). Some patients may have allodynia. The diagnosis is made on the basis of clinical symptoms, X-ray manifestations, recurrent infections, mental retardation, motor retardation, biopsy of liver and other tissues showing acidic alpha-mannosidase deficiency and absence of excessive mucopolysaccharide excretion in urine. Biochemical analysis The peripheral blood picture shows vacuolated liver tissue in neutrophils, lymphocytes and bone marrow cells, and biopsies of other tissues show increased mannosides and acidic alpha-mannosidase deficiency; the urine contains oligosaccharides of mannose. 2.X-ray examination X-ray shows mild multiple osteogenesis imperfecta, lumbar vertebral hypoplasia with bird’s beak shape; mild iliac wing exostosis, hip exostosis deformity, rib widening, epiphyseal stem of long bones, thickened metacarpals and phalanges; sclerosis of skull vault and skull base, some cases may show severe scoliosis and hunchback. 3, oral endoscopy The advent of oral endoscopy has brought a new paradigm for examination and treatment in the oral cavity. When the patient’s lesion scene is displayed in front of the patient, no more description or expertise is needed. Patients can also understand the urgency of treatment. The physician can further detect the patient’s oral lesions with the aid of clear visual images and various treatment measures taken in a timely manner.