We previously showed that overexpression of α- and β-chains in iMN9D cells altered the expression of genes involved in mitochondrial activity.12 Since then, Hb has been found accumulated in the mitochondria of human SN neurons and frontal CTX cells from post mortem PD brains.38, 39 Here we have demonstrated that Hb overexpression increases susceptibility to cell death in differentiated iMN9D cells exposed to MPP+ and rotenone. The gene discussed is GSTM1; the disease is Parkinson disease.