Although the peptide-histidine transporters PhT1 and PhT2 (SLC15A3) are present in the brain, their functional importance is unknown, and the expression of PhT1 transcripts was reported to be significantly upregulated in inflamed areas of the colon of patients with Crohn’s disease and ulcerative colitis [44]. The gene discussed is SLC15A4; the disease is Crohn disease.