近年染色体研究愈加深入 ,发现问题也愈多。染色体为基因载体 ,如若发生核型、结构异常均可引起人体表现型和智力发生障碍 ,多见形态异常或称多发畸形。现报告 1例形态正常 ,表现智力低下 ,原因为染色体结构异常所致。病例　戴某 ,女 ,汉族 ,以智力低下、抽搐 4年为主诉就诊 9 In recent years, more and more in-depth study of chromosomes and found that more problems. Chromosomes as a gene carrier, if the occurrence of karyotype, structural abnormalities can cause the human body manifestations and mental disorders, more common abnormalities or multiple deformities. Now report a normal form, the performance of mental retardation, due to chromosomal abnormalities caused. Case Dai, female, Han nationality, with mental retardation, twitch 4 years as the main complaint treatment 9