Western blot analysis of tissue protein extracts from PD and AD brains separated by 2-D gel electrophoresis revealed increased levels of DJ-1, while mass spectrometric analysis showed that DJ-1 was irreversibly oxidized by carbonylation and methionine oxidation, suggesting the possible association of oxidative damage to DJ-1 with sporadic PD and AD [131]. Here, PARK7 is linked to Alzheimer disease.