Phenotypic Characterisation of Autosomal Recessive PARK6-linked Parkinsonism in Three Unrelated Italian Families

The clinical features of nine patients (three women and six men) affected by PARK6-linked parkinsonism, belonging to three unrelated Italian families, are reported. The occurrence of affected men and women within one generation suggested an autosomal recessive mode of inheritance in all three families. Mean age at disease onset was 36 +/- 4.6 years; all cases except one presented with asymmetrical signs, consisting of tremor and akinesia of one upper limb or unilateral short step gait. Affected individuals had a mean age of 57 +/- 8.5 years, and average disease duration was 21 +/- 7.8 years. Parkinsonian features included benign course, early onset of drug-induced dyskinesias, and a good and persistent response to levodopa. There were no other associated features (i.e., pyramidal or cerebellar signs, dysautonomia, or diurnal fluctuations unrelated to drug treatment). Cognition was unaffected. The clinical picture was remarkably similar in all patients; no relevant family-related differences were found. PARK6 disease is a new form of early-onset parkinsonism without other atypical clinical features.