Four genes associated with the enriched pathway “Protein processing in ER” were chosen for investigation—ERN1, P4HB, SELENOS and SSR3. The upregulated expression by WD of ERN1, SELENOS and SSR3 in the rostral SON, and ERN1 and P4HB in the caudal SON suggests the functional importance of this pathway during WD. This evidence concerns the gene P4HB and Wilson disease.