IT15基因中 (CAG)n三核苷酸重复序列的异常扩增是导致Huntington舞蹈病 ,(HD)的主要原因 ,我们应用巢式PCR、琼脂糖凝胶电泳等方法 ,通过在分子水平上检测 (CAG)n的扩增片段的长度 ,对一家族性HD家系中自愿作症前诊断的11个高危风险者进行了基因诊断。发现正常人的扩增片段约 12 0bp ,HD基因携带者除有 1条未正常扩增片段外 ,还有 1条异常的长约 2 0 0bp的扩增片段。除HD先证者外 ,共检出 2个HD基因携带者。为临床上进行HD高风险者的检出及随后的产前诊断 ,避免患儿的出生提供了一种简便、易行的检测方法。 Abnormal amplification of trinucleotide repeats in the IT15 gene (CAG) n is the major cause of Huntington’s disease, (HD). We used nested PCR and agarose gel electrophoresis to detect (CAG) n was used to genotype the 11 high-risk individuals who were diagnosed pre-eclampsia in a familial HD family. The amplified fragment was found to be about 120 bp in normal individuals. In addition to an unamplified fragment, there was an abnormally amplified fragment of about 200 bp in the HD gene carrier. In addition to the HD proband, a total of 2 HD gene carriers were detected. It is a simple and easy method to detect the high risk of HD in the clinic and the subsequent prenatal diagnosis to avoid the birth of children.