Paulson G W
Res Publ Assoc Res Nerv Ment Dis. 1976;55:317-29.
HD is a dominantly inherited disorder that affects mental and motor systems and includes a rigid form as well as the better known choreic form. Many articles have been devoted to predicting the future onset of the disease in patients who are at risk, but none of the suggested predictors is currently considered completely reliable. Members from individual families do tend to show a similar age of onset, and similar intellectual and motor abnormalities do develop within a single family; but the presence or absence of this dominant gene of high penetrance is not usually certain until the obvious physical signs appear. Predictive tests are of importance not only to decide which person may develop the disorder, but they may also offer a clue to associated or causal features of the disease. This chapter is a review of reported predictive tests in HD, emphasizing the rationale for their use. Psychological testing has often been abnormal early in the course of the disease of some patients, particularly when motor dexterity or apraxia is tested. Family members often insist that various psychological traits enable them to predict which members are affected by the gene. These opinions are summarized. Neurophysiologic tests are briefly reviewed, including new data on increased liklihood of H-reflexes in HD. Electroencephalography was once touted as a possible predictive test but, although there is frequently an association of a low voltage EEG activity with HD, this change is too variable for certainty in prediction. Pneumoencephalography with specific measurements of caudate atrophy is of clinical interest, but a pneumoencephalogram is rarely needed for diagnosis and caudate atrophy may not actually be an early sign. Metabolic changes in HD include the biochemical effects of hypothalamic dysfunction, changes in growth hormone, and reported change in GABA levels in the CSF or brain. Provocative tests have utilized numerous drugs in an attempt to predict the onset of the disease, including particularly physostigmine and L-DOPA. All of the tests elucidate peculiarities of the disease, and all are of ethical as well as neurological interest. Many of the provocative tests utilize quantification of known neurologic features of the disease, such as reduction in saccadic movements of the eye, increased reflexes, or patterns of movement. The ethical problems in predictive tests, especially tests intended to provoke features of the disease, have been a matter of quiet controversy. Should a nontreatable disease be overtly diagnosed? And if so, will it benefit the patient? Can any of the tests tend to accelerate the patient's decline, either by physical or by psychological trauma? This chapter reviews the various predictive tests and their rationale and concludes that none of the tests are totally reliable. Many offer interesting insights into the effects of HD and do broaden the overall significance of this fascinating disorder of basal ganglion function.
亨廷顿舞蹈症（HD）是一种显性遗传疾病，会影响精神和运动系统，包括一种较为严重的形式以及更为人熟知的舞蹈症形式。许多文章致力于预测有患病风险患者疾病的未来发病情况，但目前所提出的预测指标中没有一个被认为是完全可靠的。来自各个家庭的成员确实倾向于表现出相似的发病年龄，并且在单个家庭中确实会出现相似的智力和运动异常；但在明显的体征出现之前，这种高外显率显性基因的存在与否通常并不确定。预测性检测不仅对于确定哪些人可能会患上这种疾病很重要，而且还可能为该疾病的相关特征或病因提供线索。本章回顾了已报道的HD预测性检测，重点强调了其使用的基本原理。在一些患者疾病过程的早期，心理测试往往就会出现异常，尤其是在测试运动灵活性或失用症时。家庭成员常常坚称各种心理特征使他们能够预测哪些成员受到了该基因的影响。这些观点在此进行总结。简要回顾了神经生理学检测，包括关于HD中H反射增加可能性的新数据。脑电图曾被吹捧为一种可能的预测性检测方法，但是，尽管低电压脑电图活动与HD之间经常存在关联，但这种变化过于多变，无法用于确定性的预测。对尾状核萎缩进行特定测量的气脑造影具有临床意义，但诊断很少需要气脑造影，而且尾状核萎缩实际上可能并不是早期体征。HD中的代谢变化包括下丘脑功能障碍的生化影响、生长激素的变化以及脑脊液或大脑中γ-氨基丁酸（GABA）水平的报道变化。激发试验使用了多种药物来试图预测疾病的发作，尤其包括毒扁豆碱和左旋多巴。所有这些检测都阐明了该疾病的特性，并且在伦理以及神经学方面都具有研究价值。许多激发试验利用了对该疾病已知神经学特征的量化，例如眼球扫视运动减少、反射增强或运动模式。预测性检测中的伦理问题，尤其是旨在引发疾病特征的检测，一直是一个存在着悄然争议的问题。是否应该公开诊断一种无法治疗的疾病？如果是这样做会对患者有益吗？任何一种检测是否会通过身体或心理创伤加速患者的病情恶化？本章回顾了各种预测性检测及其基本原理，并得出结论，没有一种检测是完全可靠的。许多检测为HD的影响提供了有趣的见解，并且确实拓宽了这种迷人的基底神经节功能障碍疾病的整体意义。
