DRD1 protein expression in MD/CUS rats was significantly lower than that in MD/control rats (post hoc, p<0.05), non-MD/CUS rats (post hoc, p<0.05), or non-MD/control rats (post hoc, p<0.05), but no significant group differences on DRD1 protein expression were found among the other three groups(post hoc, ps>0.05) (Table 3). The gene discussed is DRD1; the disease is Menkes disease.