There have been no large epidemiological studies on the incidence and prevalence of the PPA variants. Though it most likely has been underestimated, onset of PPA has been found to occur in the sixth or seventh decade. There are no known environmental risk factors for the progressive aphasias. However, one observational, retrospective study suggested that vasectomy could be a risk factor for PPA in men. These results have yet to be replicated or demonstrated by prospective studies. PPA is not considered a hereditary<unk> . However, relatives of a person with any form of frontotemporal lobar degeneration, including PPA, are at slightly greater risk of developing PPA or another form of the condition. In a quarter of patients diagnosed with PPA, there is a family history of PPA or one of the other disorders in the FTLD spectrum of disorders. It has been found that genetic predisposition varies among the different PPA variants, with PNFA being more commonly familial in nature than LPA or SD. The most convincing genetic basis of PPA has been found to be a mutation in the GRN gene. Most patients with observed GRN mutations present clinical features of PNFA, but the phenotype can be atypical.
symptom of Alzheimer's disease
medical cause of Dementia
symptom of Lesch–Nyhan syndrome
symptom of Amyotrophic lateral sclerosis
symptom of Multiple sclerosis
symptom of Brain tumor
symptom of Myotonic dystrophy
symptom of Narcolepsy