[A 14-year management of an early-onset female Danon disease carrier: analysis of family clinical phenotype and transplant efficacy].

Objective: To investigate the clinical characteristics, disease progression pattern, genetic variant features, and therapeutic effect of heart transplantation in a family with Danon disease. Methods: This study is a single-center retrospective case analysis. A proband with Danon disease who was diagnosed and treated at Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College between January 2009 and July 2024 and underwent heart transplantation was selected. Retrospective data were collected, including medical history, imaging findings (echocardiography, cardiac magnetic resonance), electrocardiogram, laboratory indicators, pathological examination results, and genetic testing results of the proband and her family members. Regular follow-up was conducted to evaluate the patient's disease progression and post-transplant recovery. Results: The proband was a 23-year-old female with an onset age of 7 years. Initially, the patient presented with non-obstructive hypertrophic cardiomyopathy (maximum left ventricular wall thickness: 29 mm) accompanied by reduced diastolic function. At 19 years old, the disease progressed to dilated cardiomyopathy (left ventricular end-diastolic diameter: 61 mm; left ventricular ejection fraction: 35%). At 22 years old, she was diagnosed with end-stage heart failure (cardiac index: 2.4 L·min-1·m-2). Genetic testing revealed that the patient carried a pathogenic heterozygous variant of the LAMP2 gene c.459C>A (p.Cys153Ter). She underwent orthotopic heart transplantation at 22 years old, and during 3 years of post-transplant follow-up, her cardiac function remained normal (left ventricular ejection fraction >60%). The patient's mother carried the same genetic variant and underwent heart transplantation at 29 years old. Conclusion: Despite being female, the Danon disease patient in this case exhibited clinical features of rapidly progressive cardiomyopathy. Heart transplantation is an effective treatment for patients with end-stage Danon disease, with significant long-term therapeutic effects confirmed by post-transplant follow-up. Clinicians should be alert to the possibility of Danon disease in young patients with hypertrophic cardiomyopathy. Early genetic testing helps confirm the diagnosis and provides a basis for clinical intervention.