利用聚合酶链反应（ＰＣＲ）和限制性内切酶ＭｓｅⅠ酶解分析，发现我国人群凝血因子ＩＸ（ＦｌＸ）基因５’侧翼－６９８位核苷酸存在ＭｓｅＩ多态性，该多态性由８３ｂｐ／５８ｂｐ＋２５ｂｐ组成。在受检的１１８个ＦＩＸ基因中，二者基因频率分别为０．６３５和０．３６５，多态性信息量为０．４６３。此系我国人群中发现的第二种限制性片段长度多态（ＲＦＬＰ），有助于血友病乙携带者的检测及产前基因诊断。 Using polymerase chain reaction (PCR) and restriction endonuclease Mse I digestion analysis, it was found that there was MseI polymorphism in the 5’-flanking -698 nucleotides of human coagulation factor IX (FlX) gene. The polymorphism consisted of 83 bp / 58bp + 25bp composition. Among the 118 FIX genes examined, the frequencies of the two genes were 0.635 and 0.365 respectively, and the amount of polymorphic information was 0.463. This is the second restriction fragment length polymorphism (RFLP) found in our population, contributing to the detection and prenatal genetic diagnosis of hemophilia B carriers.