目的　明确 Smith- Fineman- Myers综合征 (Smith- Fineman- Myers syndrome,SFMS)与 X连锁核蛋白 (X- linked nuclear protein,XNP)基因之间的连锁关系。方法　采用聚合酶链反应结合变性聚丙烯酰胺凝胶电泳方法 ,分析 SFMS家系中各成员 XNP基因内多态位点基因型。结果　两个多态位点中 ,XNPSTR1有多态 ,家系分析结果表明 XNP基因与 SFMS致病基因之间存在重组。结论　 XNP基因不是导致中国山东 SFMS家系的致病基因 ,SFMS存在位点异质性 Objective To determine the linkage between Smith-Fineman-Myers syndrome (SFMS) and X-linked nuclear protein (XNP) gene. Methods Polymerase chain reaction (PCR) combined with denaturing polyacrylamide gel electrophoresis was used to analyze the genotypes of polymorphic loci in XNP gene of members of SFMS family. Results There were polymorphisms in XNPSTR1 among the two polymorphic loci. The results of pedigree analysis showed that recombination existed between XNP gene and SFMS causative gene. Conclusion XNP gene is not the causative gene of SFMS pedigrees in Shandong, China, but SFMS is heterogeneous