目的研究智力低下患者的遗传学原因和预防方法。方法采用人类外周血淋巴细胞培养及染色体标本制备方法,从细胞遗传方面对563例智力低下患者的遗传学原因进行分析。结果检出异常核型188例,检出率33.39%。其中2例为世界首报核型。结论染色体异常是导致智力低下的重要原因,产前诊断是防止出生染色体异常引起的智力低下患儿的最有效的方法。 Objective To study the genetics and prevention of mental retardation in patients. Methods Human peripheral blood lymphocyte culture and chromosome preparation methods were used to analyze the genetic causes of 563 cases of mental retardation in cytogenetics. Results 188 cases of abnormal karyotype detected, the detection rate was 33.39%. Two of them were the world’s first karyotype. Conclusions Chromosomal abnormalities are the major causes of mental retardation. Prenatal diagnosis is the most effective method to prevent mental retardation in children with birth defects.