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目的:探讨Huntington病(Huntington disease,HD)的临床和遗传特征。方法:对收集的2个中国汉族HD家系患者的临床资料进行综合分析,应用聚合酶链式反应及基因扫描方法对其中9例家系成员的IT15基因的三核苷酸重复序列进行分析。结果:在两个家系中确诊了6例患者(男女均有发病),患者IT15基因的基因型均为杂合子,致病CAG重复拷贝数介于40~78次。两个家系中子代较父代发病年龄提前,家系2中可见发病年龄与CAG重复拷贝数呈负相关。6例患者中有1例为少年型HD,其临床表现明显不同于成人型,以肌张力障碍为主要表现。结论:HD是一种由CAG重复序列异常扩增所致的神经变性病,存在遗传早现现象;少年型HD的临床表现不同于成人型,CAG重复拷贝数与发病年龄及疾病严重程度有关。
Objective: To investigate the clinical and genetic characteristics of Huntington disease (HD). Methods: The clinical data of two Chinese Han pedigrees were collected and analyzed. The trinucleotide repeats of IT15 gene in 9 pedigrees were analyzed by polymerase chain reaction and gene scanning. RESULTS: Six patients (both men and women) were diagnosed in both pedigrees. The genotypes of IT15 were heterozygous and the number of repeat CAGs was between 40 and 78 times. The age of onset of neonate in the two families was earlier than that of the father, and the age of onset in the family 2 was negatively correlated with the number of replicates of CAG. One of the 6 patients had juvenile-onset HD, whose clinical manifestations differed significantly from that of adults, with dystonia as the main manifestation. CONCLUSIONS: HD is a neurodegenerative disease caused by abnormal amplification of CAG repeats. It has a premature inheritance phenomenon. The clinical manifestations of juvenile HD are different from those of adult type. CAG repeat copy number is related to age of onset and disease severity.