Abstract 18811: Heart Failure in a Carrier of Danon Disease

Abstract

Background: Danon Disease is a rare X-linked dominant genetic condition characterized by hypertrophic cardiomyopathy, skeletal muscle myopathy, and intellectual disability, among other serious complications. The disease is a lysosomal storage disorder in which a mutation in the LAMP-2 gene causes a defect in the lysosome membrane and an accumulation of glycogen in vital tissue including cardiac muscle cells. It occurs more commonly in males, who are also more severely affected than females with this condition. There are no specific treatments available, although studies involving gene therapy have been ongoing. Patients with Danon Disease often require heart transplantation as treatment for end-stage heart failure. Description of Case: A 37-year-old female with a known family history of Danon Disease was discovered to be a carrier of the LAMP-2 mutation after presenting to the hospital with dizziness and palpitations. An echocardiogram obtained at the time of diagnosis revealed left ventricular hypertrophy and left ventricular apical thrombus with normal ejection fraction. She was started on anticoagulation and began following closely with a heart failure clinic. Since diagnosis, she has had multiple echocardiograms which have shown a steady decline in her ejection fraction to 25% and biventricular failure. An ICD was placed, with no shocks ever administered. She has had multiple hospital admissions for exacerbations of heart failure since diagnosis. Telemetry monitoring during these admissions revealed frequent premature ventricular contractions attributed to the patient’s severe cardiomyopathy. Despite continuation of guideline-directed medical treatment, this patient’s systolic heart failure is anticipated to continue worsening. She will likely require heart transplant, for which evaluation has already been initiated. Discussion: Danon Disease is a rare lysosomal storage disorder that often involves progressively worsening cardiomyopathy. Individuals with a known family history of this condition should be referred early for genetic testing. If found to have the condition or be a carrier, they should begin following with a heart failure specialist and consideration for advanced therapies, like transplant, should be initiated.