染色体病（The chromosome disease）.doc

染色体病（The chromosome disease） Chapter xii chromosomal diseases The number of chromosomes or abnormalities in the structure is called chromosomal disorder. Chromosomal diseases are divided into three types: autochromosomal disease, sexual chromosomal disease and chromosome abnormality. Chromosomal diseases have the following characteristics in clinic and heredity: Patients with chromosomal diseases have congenital malformations (including special faces), growth, intellectual or sexual development, and special skin lines. (2) the vast majority of patients with sporadic chromosomes, namely parents normal chromosome, distortion of chromosomes from parent germ cells or fertilized egg early cleavage new chromosome aberration, these patients often have no family history (3) a minority of patients with chromosome structure distortion by genetic and phenotypic normal parents, one of its parents for balancing the structure of chromosome rearrangement is carried, the aberration of chromosome is passed on to their offspring, cause chromosome imbalances of the offspring and cause disease, these patients often accompanied by family history. Autosomal disease is a disease caused by an abnormal number of chromosomes or abnormal structures. Autosomal diseases account for about two thirds of chromosomal diseases. Patients generally have severe or obvious congenital malformations, intellectual and growth retardation, often accompanied by special skin striations, known as triad. Down syndrome The incidence of Down syndrome The incidence of DS in newborns is about 1/1000 ~ 2/1000 Clinical manifestations: General birth height, low weight, low muscle tone; Stunted growth, low intelligence; Special features: head small, round, flat, flat nose root, small palpebral fissure and outward tilt, too wide apart, epicanthus, tongue often overhang, often salivate, small ears, ear low, auricle deformity; The cartilage is stunted, the limbs are short, and the hand is wide and fattened, with the passin