现已发现的人类染色体数目和结构畸变3000余种,染色体病综合征100余种,除携带者和少数性染色体异常外,智力低下和生长发育迟缓几乎是所有染色体异常者的共同特征。因此,染色体异常的孩子无论对家庭还是对社会都是沉重的负担。染色体结构异常包括易位和倒位,染色体重复相对较少 It has been found that the number of human chromosomes and structural aberrations of more than 3,000 species, more than 100 kinds of chromosome disease syndrome, in addition to carriers and a few chromosomal abnormalities, mental retardation and growth retardation is almost common to all chromosomal abnormalities. Therefore, children with chromosomal abnormalities are a heavy burden on both families and society. Chromosome structural abnormalities include translocation and inversion, chromosomal duplication is relatively small