A form of Parkinson disease with age of onset between 21 and 45 years, rigidity, painful cramps followed by tremor, bradykinesia, dystonia, gait complaints, falls and other non-motor symptoms. A slow disease progression and a more pronounced response to dopaminergic therapy are also observed in most forms. The exact etiology is still unknown. Gene mutations have been implicated in some cases, most cases are sporadic however familial cases have been reported in which an autosomal recessive mode of inheritance has been suggested. [from
SNOMEDCT_US]