<b>Study and results:</b> The first-in-human in vivo CRISPR/Cas9 trial of TTR Gene editing by NTLA-2001 in patients with Transthyretin Amyloidosis and cardiomyopathy was designed to evaluate the safety, tolerability, efficacy, and pharmacokinetic and pharmacodynamic responses to IV NTLA-2001 administration and its effect on serum transthyretin (TTR) levels in patients with ATTR amyloidosis and cardiomyopathy. Here, TTR is linked to Familial transthyretin-related amyloidosis.