Indeed, we identified a DUOX2-positive population in ECO (data not shown); However, the expression of ACE2 was not observed in either PSC or non-PSC ECO derived from the large bile duct, and ACE2 expression appears to be limited to the intrahepatic cholangiocytes. The gene discussed is DUOX2; the disease is endocrine-cerebro-osteodysplasia syndrome.