The extent of dopaminergic deficiency in our transgenic animal strains is strongly age-dependent due to the chronic–progressive nature of neurodegeneration; it has already been demonstrated that Leu9′Ser α4* nAChR mice present with a reduction of both nigral dopaminergic cell loss and striatal TH+ dopaminergic nerve terminals of ~30–40% [32]. The gene discussed is CHRNA4; the disease is hyperinsulinemic hypoglycemia, familial, 4.