In August 2024, a baby named KJ Muldoon rewrote the future of medicine. Born in the US with an ultra-rare genetic disorder, KJ suffered from a defect that caused toxic ammonia to accumulate in his blood—a condition usually fatal within the first months of life. Conventional options were bleak: a liver transplant or palliative care. Instead, his doctors attempted something unprecedented—a fully personalised gene-editing therapy designed for a single human being.
At the Children’s Hospital of Philadelphia, paediatrician Dr Rebecca Ahrens‑Nicklas collaborated with Dr Kiran Musunuru of the University of Pennsylvania. Using CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) technology, scientists corrected a single faulty letter in KJ’s DNA that disrupted a vital liver enzyme. From design to delivery, the therapy was developed in just six months. The outcome was remarkable—KJ survived, improved steadily, and was eventually discharged after spending 307 days in the hospital.
This moment marks a fundamental shift in medicine. Earlier, gene-editing therapies were designed for groups of patients with the same disease, such as sickle cell disease or beta thalassemia. KJ’s treatment was different—it was created for one individual. The roots of this revolution can be traced back to 2020, when Dr Jennifer Doudna of the US and Dr Emmanuelle Charpentier of France won the Nobel Prize in Chemistry for developing CRISPR‑Cas9 gene-editing technology. For the first time, humanity gained the ability to precisely cut and edit DNA—the very code of life. With this power came an unsettling ethical question: are we now “playing God”?
This debate intensified in November 2018, when Chinese scientist He Jiankui announced the birth of the world’s first gene-edited babies—Lulu and Nana. He claimed to have altered their DNA to protect them from HIV. The global scientific community responded with outrage, citing grave ethical violations and lack of transparency. His actions became a cautionary tale of how powerful technologies can be misused.
Scientists are using gene editing to engineer immune cells, such as CAR‑T cells, enabling them to better recognise and destroy cancer cells. Clinical trials are underway for certain leukaemias, lymphomas and solid tumours. Neurological conditions, including Huntington’s disease and some forms of inherited childhood blindness, are also targets of experimental gene‑editing approaches.
These therapies differ significantly from KJ Muldoon’s case. Most current treatments are standardised for a disease population and involve editing cells outside the body. KJ’s therapy was delivered directly into his body and uniquely tailored to his DNA, making it complex, expensive and time‑sensitive.
The risks are real. Gene editing can cause unintended “off‑target” changes, potentially leading to cancer or other long‑term complications. Costs are enormous. Ethical concerns include equity, informed consent and the slippery slope toward non‑medical genetic enhancement.
For India, the implications are profound. The country bears a high burden of genetic diseases such as sickle cell disease, thalassemia and rare metabolic disorders. Gene editing offers immense hope but also raises urgent questions about affordability, access, regulation and health care infrastructure. India will need robust ethical frameworks, public‑sector investment and international collaboration to ensure these breakthroughs benefit society as a whole, not just a privileged few. Gene editing is no longer science fiction. The question is not whether we can rewrite life—but how wisely, fairly and humanely we choose to do so.
Shyla Jovitha Abraham is a health and wellness writer, based in Cleveland, and Dr Jame Abraham is chairman, department of hematology/medical oncology and professor of medicine at Cleveland Clinic. The views expressed are his own and do not represent the views of Cleveland Clinic.