ppa is not considered a hereditary disease. 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.