HINT2 and Parkinson disease: Based on their functional properties we chose to pursue DAN (differential screening-selected gene aberrant in neuroblastoma), a secreted Bmp antagonist that has previously been shown to play a role in semicircular canal formation [23]; VAMP2, a synaptosomal protein involved in exocytosis [24-26]; and the mitochondrial proteins HINT2, SLC25A25 (SCAMC2), and PINK1, a mitochondrial kinase which has been found to be mutated in inherited forms of Parkinson's disease [27].