However, mutated forms of PINK1 and Parkin are unable to mediate this process, thus by impairing this process, PD-causing mutations of PINK1 and Parkin may impede mitophagy, cause the accumulation of defective mitochondria, potentially initiate apoptotic events, and, ultimately, lead to neurodegeneration in PD [94]. This evidence concerns the gene PINK1 and Parkinson disease.