Parkinson’s disease caused by Parkin gene mutations is associated with an important and homogeneous loss of dopaminergic neurons of the substantia nigra pars compacta, which is different from those observed during the idiopathic Parkinson’s disease. The corresponding dopaminergic deficit should be associated with an excellent reactivity to levodopa, to a cognitive deficit and to behavioural and/or psychiatric attitudes, in relation with the massive alteration of dopaminergic efferences.