Hereditary spastic paraparesis and spinocerebellar ataxia

At a glance

• Both are inherited, slowly progressive neurodegenerative disorders that present in adult clinics as an unexplained gait disorder with a family history. Neither has a disease-modifying treatment, so the physician's job is to exclude treatable mimics, choose the right genetic test, organise symptomatic and disability support, and arrange counselling for relatives.
• HSP is a length-dependent degeneration of the corticospinal tracts: spastic legs, preserved arms.
• SCAs are mostly autosomal dominant repeat expansion disorders of the cerebellum and its connections. The general approach to ataxia and the other genetic ataxias (Friedreich, CANVAS, FXTAS) is in cerebellar disorders.