Danon Disease: A Clinical And Cardiovascular Magnetic Resonance Study

Part I:Clinical Features and Cardiovascular Magnetic Resonance Characteristics in Patients with Danon DiseaseAIMS Danon disease is a rare X-linked dominant genetic disease.Previous studies mainly concentrated on case reports with limited patient numbers,and even fewer articles focusing on the characteristics of cardiac magnetic resonance(CMR).In order to improve the level of diagnosis and treatment of Danon disease,we investigate the clinical spectrum,CMR imaging characteristics,and outcomes of Danon disease accumulated in National Cardiovascular Disease Center,Fuwai Hospital in recent 7 years.MATERIALS AND METHODS This retrospective study searched all patients who were referred for CMR examination at Fuwai Hospital between 2014 to 2020.Those patients with genetic and/or pathology confirmed Danon disease were enrolled in this study.The clinical presentation,laboratory examinations,pathology/genetic analysis,electrocardiography,echocardiography,and CMR characteristics were collected from the electronic medical records and follow-up by telephone before March 2021.RESULTS 8 patients with Danon disease include 7 male patients and 1 female patient were enrolled,and their ages ranged from 8 to 28.7 out of 8 patients suffered from hypertrophic cardiomyopathy phenotype of Danon disease,while 1 patient had dilated cardiomyopathy phenotype.Quantitative strain assessment by feature tracking technique showed decreased strain of left ventricular and left atrial in patients with Danon disease.In some cases,late gadolinium enhancement(LGE)was localized in the apex and right ventricular insertion points,while others showed that LGE was diffusely distributed in left ventricular including subendocardial and transmural patterns,but the interventricular septum is relatively preserved.Also,T1 mapping(total 3 cases)showed an increase in native T1(mean 1313.3 ms)and extracellular volume fraction(ECV;mean 39.17%).CONCLUSIONS Most of myocardial Danon disease showed hypertrophic cardiomyopathy phenotype and a few showed dilated cardiomyopathy phenotype.Comprehensive CMR played a unique role in the diagnosis,evaluation and prognosis of Danon disease.Part ?:Comparison of Cardiovascular Magnetic Resonance Characteristics Between HCM and HCM Phenotype of Danon DiseaseAIMS In most cases,it is difficult to distinguish hypertrophic cardiomyopathy(HCM)phenotype of Danon disease from HCM,and there is still none comparative study between them.To provide optimal non-invasive imaging parameters for differential diagnosis,we compared the cardiovascular magnetic resonance(CMR)characteristics between HCM and HCM phenotype of Danon disease.MATERIALS AND METHODS This retrospective study searched patients who were referred for CMR examination at Fuwai Hospital between 2014 to 2020.HCM patients with twice the number of HCM phenotype of Danon disease cases were included,and they were matched based on gender and with/without left ventricular(LV)outflow tract obstruction.The clinical presentation,laboratory examinations and CMR characteristics were collected from the electronic medical records and follow-up by telephone before March 2021.RESULTS 7 patients with HCM phenotype of Danon disease and 14 patients with HCM were enrolled.Generally,the age of onset of Danon disease is earlier than that of HCM[15(8,23)vs.30(25,37)years old,P=0.001],and the laboratory parameters are 4-6 times higher than the normal high limit.In addition,LGE is more likely to be distributed along the subendocardium in Danon disease(42.9%vs.0.0%,P=0.026),and the LV free wall(100%vs.28.6%,P=0.004)and apical(85.7%vs.14.3%,P=0.003)were more likely to be involved,but the interventricular septum(IVS)is relatively preserved(100%vs.35.7%,P=0.007).However,LGE is more likely to involve midwall in HCM(78.6%vs14.3%,P=0.016).Feature tracking technique showed that the strain of LV and left atrium was damaged in varying degrees in Danon disease,and were more significant than that in HCM.CONCLUSIONS Characteristic LGE is the optimal non-invasive imaging parameters for differential diagnosis of HCM phenotypic Danon disease and HCM.Danon disease should be considered in "HCM patients" with higher LGE mass mismatched with age,LGE distributed in subendocardial,apical and LV free wall,and IVS preservation tendency.