Which neurodegenerative disorder is autosomal dominant and characterized by early behavioral changes, motor symptoms, psychomotor slowing, executive dysfunction, and subcortical striatal involvement?

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Huntington disease is defined by an autosomal dominant inheritance and a characteristic combination of early behavioral changes, motor symptoms, psychomotor slowing, and executive dysfunction with subcortical striatal involvement. The genetic cause is a CAG repeat expansion in the HTT gene, leading to degeneration of the caudate and putamen. This subcortical damage produces slowed thinking and movement (psychomotor slowing) and impaired executive function, while the behavioral changes (apathy, irritability, mood disturbances) often appear early. The pattern is classic for a subcortical dementia linked to striatal degeneration, which explains the prominent motor and cognitive symptoms together.

The other conditions don’t fit this combination as neatly. Corticobasal degeneration features cortical signs like apraxia and asymmetric movement and is not characteristically autosomal dominant. Multiple system atrophy involves parkinsonism, cerebellar signs, and autonomic failure and is typically sporadic. HIV-associated neurocognitive disorder arises from HIV infection and does not follow an autosomal-dominant inheritance pattern.