Background: Many genes/loci associated with Parkinsonian disorders have been identified. However, the genetic causes for a number of familial forms of Parkinsonian disorders remain to be elucidated.
Objective: It was the aim of this paper to review the familial progressive supranuclear palsy (PSP) cases without any known gene mutations published in the English literature.
Methods: We searched the PubMed database for reports of familial PSP cases without known mutations.
Results: We found 19 PSP families. The mean age at onset was approximately 60 years, and the mean disease duration was about 8 years. Parkinsonism and ophthalmoplegia were most frequently reported, and a vast majority of patients manifested with these two symptoms. Other symptoms such as falls, postural instability and pyramidal signs were also common. A small subset of patients transiently responded to L-dopa therapy.
Conclusion: There is an increasing number of reported familial PSP. A recently performed genome-wide association study indicated genetic factors for this condition. Furthermore, clinical, pathological and genetic investigations will open new avenues to the discovery of causative genes and new therapeutics for PSP.