21-三体综合征是先天出生缺陷中最常见的疾病之一,在我国其发生率约占活产新生儿的1/800~1/1000。18-三体综合征和13-三体综合征是仅次于21-三体综合征的常见染色体三体综合征,均表现为严重智力低下,特殊面容,常合并各种先天畸形。染色体异常是导致出生缺陷、智力障碍的重要原因,目前尚无有效的治疗方法。故只能通过产前早发现、早诊断、早终止妊娠控 21-trisomy syndrome is one of the most common birth defects in congenital birth defects, its incidence in China accounts for about 1/800 ~ 1 / 1000.18-trisomy and new trisomy 13 Levy is second only to 21-trisomy syndrome, a common trisomy syndrome, are manifested as severe mental retardation, special face, often combined with a variety of congenital malformations. Chromosomal abnormalities are the major causes of birth defects and mental retardation. There is no effective treatment. It can only be detected early through prenatal, early diagnosis, early termination of pregnancy control