Proof of concept mRNA therapy in liver inherited metabolic diseases has increased in frequency in recent years (36, 37, 63, 64), supporting data for early phase clinical trials for ornithine transcarbamylase (NCT04442347), propionic acidemia (NCT04899310), methylmalonic acidemia (NCT04159103), and glycogen storage disease type 1A (NTC05095727). The gene discussed is OTC; the disease is propionic acidemia.