Hereditary spastic paraplegia or spinocerebellar ataxia? Not always as easy as it seems.

摘要

Hereditary spastic paraplegia (HSP) and spinocerebel-lar ataxias (SCAs) are both clinically and genetically heterogeneous groups of neurodegenerative disorders. Dysfunction of the corticospinal tract and dorsal columns, which results in spasticity and weakness of the lower extremities, is the clinical hallmark of HSP [1, 2]. The diagnosis of spastic paraparesis is typically quite straightforward in the absence of any additional neurological signs. However, HSP can be associated with other neurological clinical signs such as polyneuropathy, amyotrophy, dementia, mental retardation, ataxia, epileptic seizures, deafness and retinal degeneration, and non-neurological signs, such as cataracts, skin ichthyosis, short stature, joint contrac-tures and gastro-esophageal reflux [1]. Thus, the additional classification into an uncomplicated (or pure) or complicated (or complex) HSP phenotype has been suggested and widely accepted. It was also assumed that complicated HSP may represent a distinct genetic subtype of HSP. However, this phenotypic characterization had been proposed mostly before the dawn of molecular genetics, and the plot has thickened since then.