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Frontotemporal dementia (FTD) is the prototypical behavioural disorder arising from frontotemporal cerebral atrophy. Depending on the age range, prevalence has been estimated between 3.6 and 15 per 100,000 persons. The clinical term FTD covers a heterogeneous group of sporadic and familial neurodegenerative diseases with respect to etiology, neuropathology and biochemical features. FTD occurs primarily between the ages of 35 and 75 years. The most common presentation is an early change in personality, social behaviour, and language dysfunction, with relative preservation of memory functions. It might be associated with clinical symptoms of Parkinsonism and the amyotrophic form of motor neuron disease. Degenerative lesions detected by cerebral imaging (MRI, SPECT) mainly involve the frontal and temporal lobes. The current consensus on the pathological classification of FTD is based on the morphology and the histochemical and biochemical characterization of inclusion bodies or their absence. To date 4 subgroups of FTD have been defined: FTD with tau inclusions (Pick`s disease, corticobasal degeneration, progressive supranuclear palsy, familial FTD with Tau gene mutations; FTD lacking distinctive histopathology; FTD with ubiquitin-positive motor neuron disease-type inclusions; and FTD with neurofilament-positive inclusions. Antibodies against tau, ubiquitin and neurofilaments are used for the specification of inclusions. The characterization of familial forms of FTD (25 to 40% of patients) enabled the identification of 3 gene loci with subsequent characterization of the tau gene as one FTD disease gene in 10-30% of familial cases. In spite of the progress in the clinical diagnosis, to date a definite diagnosis and discrimination of the single FTD entities is still only possible by neuropathological examination of the brain. Management is only symptomatic. |