Genetic disorders of fetus include thalassemia, fetal and neonatal hemolytic diseases, Duchenne muscular dystrophy, trisomy 21 and other diseases, which can be divided into the following four categories: 1. chromosomal genetic disorders, mainly diseases caused by abnormalities in chromosomes, such as Down syndrome, Turner syndrome, etc. 2. monogenic genetic disorders, commonly albinism, hemophilia, etc.; 3. polygenic genetic disorders, including anencephaly, spina bifida, cleft lip and palate, etc.; 4, mitochondrial genetic disorders.