中文摘要：

在河南南阳收集到一个家系4代23人,其中6人患先天性智力障碍,具有轻度的面部和小母指畸形等特点,先证者伴随有癫痫的发生。采用常规的外周血培养染色体G带分析,发现先证者的核型为：46,XY,der（21）t（9;21）（9p22.2;21q22.3）pat,是部分9p三体。对该家系其他成员的染色体进行分析,发现所有患者均为部分9p三体,异常染色体均来自9号与21号染色体平衡易位携带者染色体相互易位的异常分离,因此这是一个部分9p三体综合征家系。而重复区段发生在9号染色体短臂远端一半区域（9pter→9p21）内,该区是关键区,导致智力障碍和面容轻微畸形。

英文摘要：

In this study, a four-generation Chinese family in Nanyang, Henan Province was identified with partial trisomy 9p syndrome. Of the 23 family members studied, six were characterized with mental retardation and mild facial and little finger anomalies. All affected family members demonstrated significant intrafamilial homogeneous phenotype except concomitance epilepsy in proband. On the basis of G-banding, the proband showed a translocation between chromosomes of 9p and 21q and partial 9p trisomy. The karyotype was 46, XY, der （21） t （9; 21） （9p22.2; 21q22.3） pat. Further karyotyping of other affected members and their paients in this family revealed translocation of chromosomes of 9p and 21q, with partial 9p lrisomy in all affected members. The partial 9p trisomy was the direct result of abnormal segregation of a balanced translocation cell between chromosome 9 and 21 in one of the parents. The extra distal half of the short ann of chromosome, 9pter-Op21, is responsible for the major clinical features such as mental retardation and mild facial anomaly. The cause of epilepsy in proband was discussed.