Widening of incisor spacing is one of the symptoms of mannosidosis type II. Mannosidosis type II most often develops after 2 years of age with normal physical and psychomotor development, progressive brain growth retardation 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 allogeneic hemorrhage. 1. Primary prevention (1) Premarital examination. (2) Genetic counseling. 2.The general principle in the treatment of genetic diseases is to prohibit what is contraindicated, remove what is left, and supplement what is lacking, regulate the metabolic balance, and prevent the appearance of symptoms. (1) Correction of metabolic disorders: This is currently the most important method for the treatment of hereditary metabolic diseases, and with the deepening understanding of the pathogenesis and intermediate processes of hereditary metabolic diseases, the scope of application of this method has been increasingly expanded. (2) Correction of abnormal enzyme activity.