Tzagournissakis M, Fesdjian C O, Shashidharan P, Plaitakis A
Department of Neurology, University of Crete, School of Health Sciences, Greece.
Hum Mol Genet. 1995 Dec;4(12):2239-43. doi: 10.1093/hmg/4.12.2239.
Huntington disease (HD) is an autosomal-dominant disorder of mid-life onset characterized by chorea, dementia, and oculomotor disturbances. Anticipation is commonly seen in HD families, particularly when the disease is inherited through the father. The disorder is associated with an expanded (CAG)n repeat in the IT15 gene that is unstable and tends to increase in size during meiotic transmissions, particularly of paternal origin. We have detected an unusual form of HD on the island of Crete which has distinctly different characteristics. Data from eight families encompassing 48 HD patients, showed a median age at onset 15-20 years later than that for HD occurring worldwide. There is no juvenile cases and no anticipation. DNA analysis in 12 HD patients showed expansion of the (CAG)n repeat the size of which was identical among members of each family or varied by only one unit. The elongated DNA segment was passed stably or contracted during both paternal and maternal transmissions thus indicating that unique molecular mechanisms may be operational in this form of HD.
亨廷顿舞蹈症（HD）是一种常染色体显性的中年发病疾病，其特征为舞蹈症、痴呆和眼球运动障碍。遗传早现现象在HD家族中很常见，尤其是当疾病通过父亲遗传时。该疾病与IT15基因中（CAG）n重复序列的扩增有关，该重复序列不稳定，在减数分裂传递过程中，尤其是父系来源的传递过程中，其长度往往会增加。我们在克里特岛上发现了一种不寻常的HD形式，其具有明显不同的特征。来自八个家族的48名HD患者的数据显示，发病年龄中位数比全球范围内的HD患者晚15至20年。没有青少年病例，也没有遗传早现现象。对12名HD患者的DNA分析显示，（CAG）n重复序列发生了扩增，每个家族成员的扩增大小相同，或仅相差一个单位。在父系和母系传递过程中，延长的DNA片段稳定传递或收缩，这表明这种形式的HD可能存在独特的分子机制。
