HRH2 and hereditary elliptocytosis: We did not detect in mouse or man brain tissue samples changes in the expression of the histamine degrading enzyme HNMT, whose level correlates with the histaminergic activity in the brain.46 We found no changes in histamine receptor expression except for the down‐regulation of cAMP‐stimulating H2R in Australian HE patients and in the mouse striatum (with “2−Ct” method).