PRKN and Parkinson disease: In the same manner, given that mutations in the parkin gene are common in early-onset and familial PD and that parkin expression has an inverse relation with N-myc levels in the developing mouse and human brains and in human neuroblastoma cell lines [417] and considering that N-myc is increased in reactive astrocytes of the substantia nigra of PD patients [415], N-myc is interestingly also associated with the neurotoxic process induced by meth that also increases COX1, which is linked to meth-induced DA neuronal injury expression in the ventral midbrain [418].