T‐Cell Acute Lymphoblastic Leukemia in a Young Patient With Andersen–Tawil Syndrome Successfully and Safely Treated With Intensive Chemotherapy Including Potential Precipitating Drugs: A Case Report After 3.5 Years of Follow‐up

ABSTRACT Andersen–Tawil syndrome (ATS) is a rare, hereditary channelopathy characterized by periodic paralysis, cardiac arrhythmias, and sometimes developmental anomalies. No association with hematologic malignancies has previously been reported. We describe the case of a 27‐year‐old man with genetically confirmed Type 1 ATS who developed T‐cell acute lymphoblastic leukemia. He was treated according to the GRAALL‐2014 protocol and achieved sustained complete molecular remission without allogeneic transplantation after 3.5 years of follow‐up. Management required careful adaptation to mitigate ATS‐related risks. Specifically, QT‐prolonging and neurotoxic agents were avoided or substituted, glucose infusions were minimized, and acetazolamide was introduced early. Despite exposure to high‐dose corticosteroids and anthracyclines, only moderate, self‐limited paralytic episodes occurred during intensive phases. During maintenance, ventricular ectopy and QT prolongation prompted chemotherapy dose adjustments and beta‐blocker therapy, leading to rapid normalization. This case highlights the feasibility of delivering intensive chemotherapy in ATS with tailored supportive care. Although likely coincidental, this unprecedented association raises questions about potential links between ion channel dysfunction and leukemogenesis.