WITHIN DAYS after KJ was born in Philadelphia in August 2024 it was clear that one thing was unsuitable. He was not consuming and slept an excessive amount of. Blood assessments revealed sky-high ranges of ammonia, a poisonous substance the physique normally expels. Genome sequencing confirmed that he had a uncommon genetic illness referred to as carbamoyl-phosphate synthetase 1 (CPS1) deficiency, which frequently kills in infancy, and for which no good neonatal therapy exists. Then certainly one of his medical doctors steered one thing radical: a gene-editing drug designed particularly for him.