Atherosclerosis–inflammatory disease

Huntington disease (HD) is a progressive neurodegenera-tive disorder with an established genetic origin and symp-toms that are referable to specific regions of brain disease. Cellular and molecular techniques are rapidly elucidating the pathogenesis of the disorder and are leading to ap-proaches designed to develop rational treatments. Thus, HD serves as a model for the future study of those psychiat-ric disorders in which abnormal brain function is thought to arise from predominantly genetic factors. CLINICAL FEATURES HD can be described as a triad of motor, cognitive, and emotional disturbances (1,2). Symptoms usually begin be-tween the ages of 35 and 50 years, although the onset may occur at any time from childhood to old age. Death occurs an average of 15 to 20 years after symptoms first appear, with some patients dying earlier from falls or suicide and others surviving for 30 to 40 years (Fig. 125.1). Movement Disorders The movement disorder of HD consists of two components: involuntary movements and abnormal voluntary move-ments. Chorea, or choreoathetosis, is the movement abnor-mality most frequently associated with HD. It consists of continuous and irregular jerky or writhing motions. Distur-bances of voluntary movement, however, are more highly correlated with functional disability and disease severity, as measured by the degree of brain disease. The disordered voluntary movements observed in HD include the follow-ing: abnormal eye movements, such as slow, hypometric saccades and catchy pursuit; uncoordinated, arrhythmic, and slow fine motor movements; dysphagia and dysarthria; dysdiadochokinesis; rigidity; and gait disturbances