Family genetic history includes single gene disease, polygenic inheritance and chromosomal abnormalities, such as albinism and hemophilia.
1. Single gene disease: often manifested as functional changes, can not make a certain protein, metabolic dysfunction, the formation of metabolic genetic diseases, single gene disease is divided into three kinds, dominant inheritance, recessive inheritance, sex-linked inheritance.
Dominant inheritance, such as polydactylism, primary glaucoma; recessive inheritance, such as congenital deafness, high myopia, albinism, etc.; sex-linked inheritance, related to gender, such as hemophilia, red-green color blindness.
2. Polygenic inheritance: caused by multiple genetic changes, a relationship between genes and traits, such as cleft lip, cleft palate, asthma and to schizophrenia.
3. Chromosomal abnormality: due to abnormalities in the number of chromosomes, or abnormalities in their arrangement and position, the most common is congenital stupidity.