HTRA2 variations in Taiwanese Parkinson's disease

Mutations in HTRA2 have been reported to associate with Parkinson's disease (PD). This study investigates if the genetic variants in HTRA2 contribute to Taiwanese PD. HTRA2 cDNA fragments from 80 patients with early-onset PD (onset ≤50 years) were sequenced. The identified variants were further examined for a cohort of PD and ethnically matched controls. A novel heterozygous R36W was identified in one early-onset and two late-onset PD patients, which was absent in 606 normal controls. The clinical features and 99mTc-TRODAT-1 SPECT image of the early-onset patient carrying R36W were similar to that of idiopathic PD. The R36W mutation of the patient was inherited from his mother whose SPECT revealed asymmetric reduction of 99mTc-TRODAT-1 uptake in the left striatum, suggesting that the defect of the nigrostriatal pathway may be attributable to the R36W in this family. Protein subcellular fractionation further revealed that R36W affected the processing of the proprotein after transport into mitochondria. Although the functional assays are promising, a larger cohort of both cases and controls should be screened to clarify the role of R36W in Taiwanese PD pathogenicity.