Why CMR helps in late-onset Danon cardiomyopathy. (QF_FR_103)

A 63-year-old woman with unremarkable past medical history presented with recent-onset exertional dyspnoea.  The EKG reported sinus rhythm with premature atrial complexes and echocardiogram reported concentric hypertrophy of the left ventricle. The patient was referred to cardiac MR (CMR) for suspected sarcomeric hypertrophic cardiomyopathy (HCM). Upon reinterrogation, lower limb weakness was documented. No cognitive impairment or liver enzyme alterations were found. Genetic testing confirmed Danon Cardiomyopathy. 

Pharmacologic treatment with beta-blocker and angiotensin converting enzyme inhibitors was started.  

Control CMR two years later revealed development of right ventricle hypertrophy (Figure 1 E,F). At last follow-up the patient referred adequate symptom control and genetic testing of first-degree relatives is underway. 

Diagnostic Techniques and Their Most Important Findings:

CMR showed extensive late gadolinium enhancement (LGE) with midwall and subepicardial distribution involving the septal and lateral wall , as well as basal septum sparring (Figure 1 A, B). T1 mapping (Figure 1 C) and Extracellular Volume were normal (nT1: 1034, ECV 23%). T2 mapping revealed increased values involving the lateral wall of the left ventricle at mid-basal sections (Figure 1 D). CMR findings were suggestive of non-sarcomeric HCM

 

Learning Points from this Case:

Danon disease is an x-linked inherited disease with mutations in the genes encoding the LAMP-2 protein with phenotypic profiles that differ between male and females. Due to its rare presentation, diagnosis is usually delayed and challenging, especially in women who present lower rates of cognitive impairment and muscle weakness. However, between 61-100% of women present cardiomyopathy at diagnosis with dilated or hypertrophic cardiomyopathy . Our case highlights the pivotal role of CMR in identifying Danon disease by documenting image findings that differ from those reported in sarcomeric HCM. Sarcomeric-HCM typically exhibits LGE in the hypertrophic areas including the midbasal septum which differs from the enhancement pattern in Dannon cardiomyopathy where the late enhancement pattern usually involves the lateral wall and apex with sparing to the basal septum.