Bruno FerrariFema - Machado de Assis Educational Foundation, Brazil
Title: Danon's disease: A rare case report
Introduction: Danon's disease is a dominant mutation linked to the X chromosome that is characterized by the deficiency of a protein that exist in the lysosomal membrane, Lysosome-Associated Membrane Protein 2 (LAMP2). LAMP2 plays an essential role in carrying out autophagy and degradation of lysosomal products, mainly glycogen, resulting in its accumulation. Its involvement is predominantly of cardiac, skeletal and retinal muscles, sometimes cognitive and behavioral changes and, more rarely, liver involvement. Clinically, it is common to manifest in men at the end of adolescence and occasionally in women in their fourth decade of life. Given its rarity, the actual prevalence in the general population is unknown.
Case Description: Female patient, 40 years old, white, born in the countryside, with a history of two bicaval orthopic heart transplants due to cardiomyopathy, in an outpatient consultation complaining of tachycardia on minor exertion associated with a feeling of pre-syncope and sweating. In association, he complained of dyspnea - functional class II. Absence of symptoms of right cavities. He also complained of frequent memory lapses, reduced motor strength, and cognitive impairment. Electrocardiogram (ECG) with ventricular pre-excitation pattern – short PR, delta wave, widened QRS and ventricular repolarization alteration, signs of left atrial and ventricular overload. Endomyocardial biopsy demonstrating hypertrophy of cardiomyocytes with fine vacuolation and positive intracytoplasmic corpuscles with glycogen deposition associated with interstitial fibrosis – aspect compatible with cardiomyopathy due to glycogen accumulation. Due to the high suspicion, a genetic test for Danon's disease was performed with a positive result. At the same time, the patient (G. J Male, 16 years old, brother, seeks cardiology service with similar symptoms. ECG performed with the same pattern and referred for Cardiac Magnetic Resonance; quickly diagnosed with the same condition and submitted to transplantation.
Conclusions: It is a rare condition that is difficult to diagnose and is therefore underdiagnosed. Treatment should be directed at the symptoms and a large number of patients may require a heart transplant. Given the variability of genetic transmission, genetic counseling and cardiac surveillance must be planned on a case-by-case basis, depending on the family in question. Performing the differential diagnosis in ventricular pre-excitation diseases is a critical point, especially when associated with the classic clinical triad of cardiomyopathy, skeletal muscle myopathy and intellectual impairment.
To be updated