These PoPH LSEC, Macrophage, and Cholangiocyte peri-central clusters also differentially expressed genes involved in the arginine biosynthesis pathway itself (ASL, GPT2, ARG1, GOT1, ASS1, CPS1) relative to non-PoPH cirrhosis (Fig. 2b), a pattern of gene expression absent from PoPH LSEC, Macrophage, and Cholangiocyte clusters in the intermediate or peri-portal zones (Fig. 2c, d). The gene discussed is ASS1; the disease is Cirrhosis.