Parkin-deficient mouse models of PD do not display loss of DA neurons (Goldberg et al., 2003) but do exhibit elevated extracellular dopamine levels (Goldberg et al., 2003), enhanced dopamine metabolism (Itier et al., 2003) and indications of an impaired respiratory capacity of striatal mitochondria (Palacino et al., 2004). The gene discussed is PRKN; the disease is Parkinson disease.