Cortical inhibitory deficits in Huntington's disease are not influenced by gender

Huntington's disease (HD) affects GABA-mediated inhibitory circuitry in the cortex. As there is evidence that sex hormones affect GABAergic function, we investigated whether gender modulates GABA-related pathophysiological changes in HD. Fifteen premanifest HD, 11 symptomatic HD and 16 healthy control participants were assessed with paired-pulse transcranial magnetic stimulation applied to the primary motor cortex. Cortical inhibition was significantly reduced in symptomatic HD, compared with premanifest HD and controls. There was reduced inhibition in females overall, but no Group-by-Sex interaction. These findings suggest that sex hormones do not exert a direct influence on the mechanisms underpinning cortical inhibitory deficits in HD.