Plasma testosterone in male patients with Huntington's disease: Relations to severity of illness and dementia

Huntington's disease (HD) is a neurodegenerative disorder characterized by motor, cognitive, and psychiatric symptoms and by a progressive loss among other, of dopaminergic receptors in striatum, cortex, and hypothalamus. Central dopaminergic activity has been implicated in the regulation of sex hormones. Several features of testosterone deficiency, such as reduced muscle mass, depressive mood, and cognitive impairment, are often present in HD patients, but data on their testosterone levels are lacking. We assessed plasma levels of testosterone, LH, and FSH in 42 male patients with HD, confirmed by molecular genetic analysis, and searched for differences from age‐matched healthy male subjects and for relations to CAG repeat number, age, age range, 26 to 76 (mean, 50.7 ± 12.3) years; duration of illness range, 1 to 23 (mean, 6.7 ± 6.3) years; and CAG repeat numbers from 40 to 65 (45.1 ± 3.8). Disease symptomatology was assessed using the Unified Huntington's Disease Rating Scale. Testosterone and LH levels of the patients were significantly lower compared to the levels of 44 age‐matched (mean age, 48.9 ± 13.0, range, 26–76 years) healthy men. Severity of illness was negatively related to plasma testosterone levels. Further, low testosterone levels were associated with dementia but not with depression or psychotic features. Clinical studies with selected HD patients are needed to evaluate possible beneficial effects of androgen substitution therapy on cognitive functions, depression, muscle mass and strength, general well‐being, and, eventually, neuroprotective effects. Ann Neurol 2005;57:520–525