As there are currently no treatments available that target the molecular and genetic etiologies of these three disorders, they should continue to be considered distinct
Knowledge about the clinical, pathological and genetic bases for neurodegenerative disorders is rapidly expanding. As modern molecular and genetic techniques are exploited, distinctions between disorders once considered separate diseases are beginning to blur. Recent genetic and pathological findings suggest that there are common molecular mechanisms for corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP), two atypical parkinsonian syndromes that were initially considered unrelated. Also, it is now apparent that some patients who meet the clinical criteria for frontotemporal lobar degeneration (FTLD) show CBD or PSP at autopsy. Growing awareness of the similarities between CBD, FTLD and PSP has led their classification as distinct disorders to be challenged.1,2 In particular, some authors argue that FTLD with tau mutations, CBD and PSP should all be considered as subtypes of Pick's disease.1,3 Fundamental differences between these three syndromes still exist, however, and these differences justify their continued separation.
