A baby who is the first patient in the world to be successfully treated with customized CRISPR gene editing therapy is finally returning home from the hospital.

Nine-month-old KJ Muldoon of Clifton Heights, Pennsylvania, spent over 300 days at the Children’s Hospital of Philadelphia after receiving the cutting-edge treatment. His parents, Kyle and Nicole Muldoon, opened up about their son's health journey in an exclusive interview with TODAY aired Thursday, June 4 .

Baby KJ was born last August with a rare genetic disorder called carbamoyl phosphate synthetase I (CPSI) deficiency, which caused him to spend the first year of his life in the hospital.

KJ Muldoon is the first patient customized gene-editing therapy. TODAY

People with CPSI deficiency lack an enzyme that breaks down amm

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