The largest variety of genetic diseases are monogenic diseases, which are genetic diseases controlled by a pair of alleles. The disease occurs due to mutations in the genes in the patient’s body and abnormalities in the structure and number of chromosomes, and is entirely influenced by genetic factors. The more common ones are red-green color blindness, albinism, anti-vitamin D rickets and so on. 1. Red-green color blindness: red-green color blindness is part of color blindness, divided into red blindness and green blindness. Patients can not distinguish between red and green, seen as two shades: long-wave (red, orange, yellow, green) part of the yellow, short-wave (blue, blue, purple) part of the blue. Red-green color blindness is an X-chromosome recessive disorder, with more male patients developing the disease, while female patients are gene carriers and do not develop the disease. 2. Albinism: Albinism is a kind of hereditary leukoplakia caused by melanin deficiency or synthesis disorder of the skin and accessory organs due to tyrosinase deficiency or hypoplasia. Both parents of the patient carry the albino gene and do not develop the disease themselves. If the couple carries the disease-causing gene to their children at the same time, the children will get sick. 3. Anti-vitamin D rickets: Anti-vitamin D rickets is a disease that affects the bones of the whole body mainly because of the lack of vitamin D, which leads to the inability of normal absorption of calcium salts. It is hereditary and is inherited through genes, usually from one generation to the next. Genetic disease is a disease caused by changes in the genetic material or controlled by the causative gene, refers to diseases that are completely or partially determined by genetic factors, often congenital, but also can be acquired, we recommend that patients go to the hospital for examination and treatment.