CTPS1 and pachyonychia congenita: Meanwhile, mucin 1 (MUC1), a polymorphic mucin-like protein that is overexpressed in PC, can stabilize HIF-1α and promote HIF-1α recruitment to glycolytic gene promoters (transketolase (TKT) and CTP synthase 1 (CTPS1)) in a hypoxia-dependent manner 315.