A female patient in her 30s who was a DMD carrier developed an asymptomatic decline in left ventricular ejection fraction during HER2-targeted therapy for breast cancer.
Case Report (n=1)
This case highlights the potential need for increased cardiac surveillance, cardioprotective medications, and genetic screening in patients with baseline abnormal echocardiograms prior to receiving cardiotoxic cancer therapies.
Introduction: Carriers of Duchenne muscular dystrophy (DMD) and other inherited myopathies are at risk of cardiomyopathy, and HER2-targeted therapies for breast cancer are also associated with cardiotoxicity. The coexistence of these conditions presents a novel clinical challenge. Standard baseline cardiac evaluations prior to HER2-targeted therapy do not routinely detect inherited cardiomyopathies, and genetic risk is not currently incorporated into pre-treatment assessment. Case Report: We report the case of a woman in her 30s with HER2-positive breast cancer with baseline borderline low global longitudinal strain (GLS) who was incidentally identified as a carrier of a DMD gene mutation after her son was diagnosed with DMD and developed an asymptomatic decline in left ventricular ejection fraction during treatment. Conclusion: This case highlights the potential role of increased cardiac surveillance and consideration of cardioprotective medications and genetic screening in patients with baseline abnormal echocardiograms prior to receiving cardiotoxic cancer therapies.
Desai et al. (2026) conducted a case report in HER2-positive breast cancer and Duchenne muscular dystrophy carrier (n=1). HER2-targeted therapy was evaluated on Decline in left ventricular ejection fraction. A female patient in her 30s who was a DMD carrier developed an asymptomatic decline in left ventricular ejection fraction during HER2-targeted therapy for breast cancer.