Genetic deafness is divided into two major categories: nonsyndromic genetic deafness and syndromic genetic deafness. Based on the mode of inheritance, non-syndromic hereditary deafness can be classified into four types: autosomal dominant, autosomal recessive, sex-linked (X-linked recessive, Y-linked), and mitochondrial mutation matrilineal inheritance. Each mode of inheritance has its own characteristics: 1, autosomal dominant inheritance: genealogical characteristics: one of the parents is a patient; 1/2 of the patient’s siblings have the disease, equal chances of male and female; 1/2 of the patient’s children have the disease, each birth has 50% risk for the affected child; when the parents do not have the disease, the children generally do not have the disease, only the occasional new mutation. 2, autosomal recessive inheritance: only the pure gene for the disease will develop, the genealogy is characterized by: the patient’s parents are carriers; 1/4 of the patient’s siblings have the disease and the chances of both sexes are equal; the patient’s children are generally carriers; the risk of the disease is increased in children of consanguineous marriage. (1) Genealogical characteristics of X-linked recessive inheritance: more male patients than female patients; sons can develop the disease when their parents are disease-free, and the causative gene comes from the carrier mother; brothers and uncles of the patient have 1/2 risk of developing the disease. (2) Genealogical characteristics of X-linked dominant inheritance: more females than males, females often have milder disease than males; one parent must have the disease; all daughters of male patients have the disease, sons are normal, and 1/2 of each child of female patients has the disease; continuous transmission. (3) Y-linked inheritance, father to son, son to grandson, female does not develop the disease. (4) Genealogical characteristics of maternal inheritance: the disease is transmitted to the next generation only through the female in the family, and the male cannot transmit the disease to the next generation. For example, mitochondrial diseases.