CAG 重复序列延长导致亨廷顿蛋白上生成一种细长的多聚谷氨酰胺尾巴,导致该异常蛋白裂解和生成毒性片段。[10]Wanker E, Dröge A. Structural biology of Huntington's disease. In: Bates G, Harper P, Jones L, eds. Huntington's disease. New York: Oxford University Press; 2002:327-47. 毒性片段的多聚谷氨酰胺构成容易使其交联,形成抗降解和干扰各种正常细胞功能(尤其是线粒体能量代谢)的聚集体。[11]Marchut AJ, Hall CK. Effects of chain length on the aggregation of model polyglutamine peptides: molecular dynamics simulations. Proteins. 2007 Jan 1;66(1):96-109.http://www.ncbi.nlm.nih.gov/pubmed/17068817?tool=bestpractice.com[12]Oliveira JM, Jekabsons MB, Chen S, et al. Mitochondrial dysfunction in Huntington's disease: the bioenergetics of isolated and in situ mitochondria from transgenic mice. J Neurochem. 2007 Apr;101(1):241-9.http://www.ncbi.nlm.nih.gov/pubmed/17394466?tool=bestpractice.com 然而,这些聚集体也会干扰转录、轴突和囊泡运输、细胞凋亡、蛋白酶体功能和细胞间相互作用的调节。[1]Walker FO. Huntington's disease. Lancet. 2007 Jan 20;369(9557):218-28.http://www.ncbi.nlm.nih.gov/pubmed/17240289?tool=bestpractice.com 单倍剂量不足,野生型亨廷顿蛋白水平的降低不会导致疾病。[1]Walker FO. Huntington's disease. Lancet. 2007 Jan 20;369(9557):218-28.http://www.ncbi.nlm.nih.gov/pubmed/17240289?tool=bestpractice.com 然而,它可能会导致聚集体的不良反应。正在积极研究旨在改善线粒体功能、阻断在产生毒性片段位点的亨廷顿裂解、防止突变亨廷顿基因的表达、改善细胞间相关作用、增强突变蛋白的自噬消耗和延缓细胞凋亡的治疗干预措施。[13]Stack EC, Smith KM, Ryu H, et al. Combination therapy using minocycline and coenzyme Q10 in R6/2 transgenic Huntington's disease mice. Biochim Biophys Acta. 2006 Mar;1762(3):373-80.http://www.ncbi.nlm.nih.gov/pubmed/16364609?tool=bestpractice.com[14]Graham RK, Deng Y, Slow EJ, et al. Cleavage at the caspase-6 site is required for neuronal dysfunction and degeneration due to mutant huntingtin. Cell. 2006 Jun 16;125(6):1179-91.http://www.ncbi.nlm.nih.gov/pubmed/16777606?tool=bestpractice.com[15]Peng Q, Masuda N, Jiang M, et al. The antidepressant sertraline improves the phenotype, promotes neurogenesis and increases BDNF levels in the R6/2 Huntington's disease mouse model. Exp Neurol. 2008 Mar;210(1):154-63.http://www.ncbi.nlm.nih.gov/pubmed/18096160?tool=bestpractice.com
亨廷顿病主要累及纹状体,且大多数临床特征可直接归因于这一区域的损害,包括认知障碍、行为改变和协调性缺失。[4]Hayden MR. Huntington's chorea. New York, NY: Springer; 1981.[16]Stober T, Wussow W, Schimrigk K. Bicaudate diameter: the most specific and simple CT parameter in the diagnosis of Huntington's disease. Neuroradiology. 1984;26(1):25-8.http://www.ncbi.nlm.nih.gov/pubmed/6234475?tool=bestpractice.com 然而,病理性改变也发生于多处皮层和皮层下结构。[17]Gutekunst C, Norflus F, Hersch S. The neuropathology of Huntington's disease. In: Bates G, Harper P, Jones L, eds. Huntington's disease. New York: Oxford University Press; 2002:251-75.
舞蹈症是亨廷顿病的最显著特征,由纹状体功能障碍导致。[18]Cepeda C, Wu N, André VM, et al. The corticostriatal pathway in Huntington's disease. Prog Neurobiol. 2007 Apr;81(5-6):253-71.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1913635/http://www.ncbi.nlm.nih.gov/pubmed/17169479?tool=bestpractice.com