According to these criteria, PA has as its dominant feature, a disorder of expressive language that is present at the onset of the condition and remains throughout the disease course. Other aspects of cognition are intact or relatively well preserved. Core diagnostic features include an insidious onset with gradual progression, and nonfluent spontaneous speech marked by agrammatism, phonemic paraphasias, or anomia. Supportive diagnostic speech and language features include stuttering or oral apraxia, impaired repetition, and alexia with agraphia. Early in the disease, word meanings are preserved.
Mutism occurs as a late feature.
Social skills are preserved early in the course of the disease. Other supportive features include onset before age 65. Clinical features include personality changes, hyperorality, nonfluent aphasia, bradykinesia, rigidity, and impairment of executive functions. The inheritance is autosomal dominant with a pathological locus mapped to a 2 cM interval on 17q21-22. More than 10 exonic and intronic mutations in the tau gene have been identified in patients with familial FTDP-17.