HMBS and metabolic disease: Acute intermittent porphyriais a metabolic disease that is causedby the malfunction of porphobilinogen deaminase (PBGD), a key enzymein the heme biosynthesis pathway.70 Fontanella’sgroup developed the LNP delivery system to deliver human PBGD (hPBGD)mRNA to hepatocytes, to reconstruct the expression of PBGD and keepit at a normal level.71 The results revealedthat hPBGD could be expressed by mouse hepatocytes after the LNP wasintravenously injected, which normalizes the excretion of porphyrinprecursor by urine.