PARK2 mutations and clinical features in a Chinese population with early-onset Parkinson's disease.

Our aim was to characterise PARK2 mutations and clinical features in Hong Kong Chinese with early-onset Parkinson's disease. Subjects were recruited from two major hospitals. Detailed data included demographics, age of onset, duration of disease, neurological manifestations, complications and disease severity. Genetic analysis for PARK2 mutations was performed. Thirty-four patients were recruited (mean age of onset = 39 years; mean duration of disease = 10 years). Seven patients reported a family history. The salient clinical manifestations were resting tremor (33/34), bradykinesia (33/34), rigidity (30/34), postural instability (20/34), good response to L-dopa (33/34), asymmetry at onset (31/34) and sleep benefit (12/34). Motor complications were reported in a significant number of patients, and depression was the most common nonmotor complication. Five patients were identified to have PARK2 mutations. Two sisters were compound heterozygotes for an insertion and a deletion, a novel and rare 1 bp insertion/nonsense mutation c1378_1379insG (exon 12) and the entire deletion of exon 7. Another patient was homozygous for the entire deletion of exon 6. Two carriers were identified, one with a T1321C (Cys441Arg) missense mutation in exon 12 and another with a snp within intron 4. Our study reviewed a higher prevalence of PARK2 mutations in Chinese than that previously documented. A compound heterozygous mutation within two sisters with significant differences in age of onset and phenotypic manifestations suggest that modifier affects may be present in this family.