Hypothalamic-pituitary-adrenal axis functioning in Huntington's disease mutation carriers compared with mutation-negative first-degree controls

Neurodegeneration in Huntington's disease (HD) occurs in various brain regions including the hypothalamus. In this cross-sectional study, hypothalamic-pituitary-adrenal (HPA) axis functioning was studied in 26 presymptomatic and 58 symptomatic HD mutation carriers, and 28 controls. HPA axis functioning was measured through salivary cortisol in the day curve, the cortisol awakening response (CAR), the area under the curve (AUC), the morning rise, and the dexamethasone suppression test (DST). Only the CAR was statistically different between the three groups, being explained by higher cortisol concentrations at 45 and 60 min post-awakening for presymptomatic mutation carriers compared to both symptomatic mutation carriers and controls. No differences were found for the AUC, evening and post-DST cortisol concentrations. Our study indicates a mild disturbance in morning cortisol secretion in HD mutation carriers that precedes the onset of motor symptoms.