TTR and hereditary angioedema: Phase I clinical trial data indicate that a single dose of NTLA‐2001 reduces serum TTR levels by 87%, and the maximum reduction in TTR on the 28th day was 96%, with no observable side effects.[190] Encouraged by these positive results, Cas9 mRNA and sgRNA are delivered by the same delivery platform on clinical trials to treat hereditary angioedema by knocking out the KLKB1 gene in hepatocytes.