In 1959, Ford et al. demonstrated that the disease was due to monosomy of sex chromosome X. The patient has a disorder of gonadal development and the ovaries are replaced by striated fibrous tissue. The phenotype of Turner syndrome is female in about 0.4 per 1,000 live births, and its low incidence is due to the fact that embryos with monosomy X are less likely to survive and miscarriage occurs in about 99% of cases. The disease is also the only survivable monosomy syndrome in humans. Symptoms and signs 1. Short stature is the most constant feature of the disease. 2. Mental retardation. 3. Patients with this disease are usually childish, docile and easy to get along with. 4. The external genitalia are juvenile, the gonads are not developed, the uterus and fallopian tubes are small, the ovaries are striped, the oocytes and cystic follicles are often absent, primary amenorrhea, sterility, scant pubic hair, thin vaginal mucosa, and no secretions. 5. There may be droopy eyes, inner canthus, low posterior hairline, large low ears, high palatal arch, neck webbing, black pigmented nevus, etc. Often there are also bone deformities. Serum estradiol levels are low, and follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are significantly elevated. Sex chromosomal examination is negative. The following types of karyotypes are necessary to confirm the diagnosis: ① Monosomy: 45, X0, is the most common type with typical symptoms. If 46,XX cells are predominant, most of the symptoms are mild, and about 20% of them can have puberty and menstruation, and some of them can be fertile, but the spontaneous abortion rate and stillbirth rate are high, and the risk of chromosomal aberrations in the offspring is also high. (iii) X chromosome structural aberrations: one X chromosome is missing in both long and short arms, such as 46, Xdel (Xq) or 46, Xdel (Xp), and X isochromosomes, such as 46, Xi (Xq) or 46, Xi (Xp). The 4th metacarpal bone becomes shorter. A tangent line along the 4th and 5th metacarpal bones will intersect with the 3rd metacarpal bone (not normally)