Cardiac magnetic resonance imaging in Danon disease

Cardiac magnetic resonance of hypertrophic heart phenotype: A review

Hypertrophic heart phenotype is characterized by an abnormal left ventricular (LV) thickening. A hypertrophic phenotype can develop as adaptive response in many different conditions such as aortic stenosis, hypertension, athletic training, infiltrative heart muscle diseases, storage disorders and metabolic disorders. Hypertrophic cardiomyopathy (HCM) is the most frequent primary cardiomyopathy (CMP) and a genetical cause of cardiac hypertrophy. It requires the exclusion of any other cause of LV hypertrophy. Cardiac magnetic resonance (CMR) is a comprehensive imaging technique that allows a detailed evaluation of myocardial diseases. It provides reproducible measurements and myocardial tissue characterization. In clinical practice CMR is increasingly used to confirm the presence of ventricular hypertrophy, to detect the underlying cause of the phenotype and more recently as an efficient prognostic tool. This article aims to provide a detailed overview of the applications of CMR in the setting of hypertrophic heart phenotype and its role in the diagnostic workflow of such condition.

Cardiovascular magnetic resonance findings in Danon disease: a case series of a family

Background

Cardiac involvement constitutes the primary cause of mortality in patients with Danon disease (DD). This study aimed to explore the cardiac magnetic resonance (CMR) features and progressions of DD cardiomyopathies in a family with long-term follow-up.

Methods

Seven patients (five females and two males), belonging to the same family and afflicted with DD, were enrolled in this study between 2017 and 2022. The cardiac structure, function, strain, tissue characteristics on CMR and their evolutions during follow-up were analyzed.

Results

Three young female patients (3/7, 42.86%) exhibited normal cardiac morphology. Four patients (4/7, 57.14%) displayed left ventricle hypertrophy (LVH), and mostly with septal thickening (3/4, 75%). A single male case (1/7, 14.3%) showed decreased LV ejection fraction (LVEF). Nonetheless, the global LV strain of the four adult patients decreased in different degree. The global strain of adolescent male patients was decreased compared to the age-appropriate female patients. Five patients (5/7, 71.43%) exhibited late gadolinium enhancement (LGE), with proportion ranging from 31.6% to 59.7% (median value 42.7%). The most common LGE location was the LV free wall (5/5, 100%), followed by right ventricle insertion points (4/5, 80%) and intraventricular septum (2/5, 40%). Segmental radial strain (rs = -0.586), circumferential strain (r = 0.589), and longitudinal strain (r = 0.514) were all moderately correlated with the LGE proportions of corresponding segments (P < 0.001). T2 hyperintense and perfusion defect foci were identified, overlapping with the LGE areas. During follow-up, both the young male patients exhibited notable deterioration of their cardiac symptoms and CMR. The LVEF and strain decreased, and the extent of LGE increased year by year. One patient underwent T1 mapping examination. The native T1 value was sensitively elevated even in regions without LGE.

Conclusions

Left ventricular hypertrophy, LGE with sparing or relatively less involved IVS, and LV dysfunction are prominent CMR features of Danon cardiomyopathy. Strain and T1 mapping may have advantages in detecting early-stage dysfunction and myocardial abnormalities in DD patients, respectively. Multi-parametric CMR can serve as an optimal instrument for detecting DD cardiomyopathies.

Rare Metabolic and Endocrine Diseases with Cardiovascular Involvement: Insights from Cardiovascular Magnetic Resonance - A Review

The identification of rare diseases with cardiovascular involvement poses significant diagnostic challenges due to the rarity of the diseases, but also due to the lack of knowledge and expertise. Most of them remain underrecognized and undiagnosed, leading to clinical mismanagement and affecting the patients' prognosis, as these diseases are per definition life-threatening or chronic debilitating. This article reviews the cardiovascular involvement of the most well-known rare metabolic and endocrine diseases and their diagnostic approach through the lens of cardiovascular magnetic resonance (CMR) imaging and its prognostic role, highlighting its fundamental value compared to other imaging modalities.

Cardiac Phenotype Characterization at MRI in Patients with Danon Disease: A Retrospective Multicenter Case Series

Danon disease (DD) is a rare X-chromosome-linked dominant lysosomal glycogen storage disease. Its features have seldom been reported by using cardiac MRI. This case series aimed to evaluate cardiac features of DD on the basis of MRI observations from five centers in China. From January 2010 to May 2019, 16 patients with DD (13 male patients [81%]; median age, 19 years; age range, 14-44 years) underwent MRI. The most frequent DD cardiomyopathy manifestation was symmetric hypertrophy cardiomyopathy (HCM) phenotype (nine of 16; 56%), followed by asymmetric HCM phenotype (six of 16; 38%) and dilated cardiomyopathy phenotype (one of 16; 6%). The characteristic late gadolinium enhancement features included midbasal septum sparing (14 of 16; 88%) and apex involvement (16 of 16; 100%) with a base-to-apex increasing tendency, free wall involvement (15 of 16; 94%), and extensive subendocardium involvement (14 of 16; 88%). Abnormal T2 signal (seven of 16; 44%) and resting perfusion defect (14 of 16; 88%) were not uncommon in patients with DD. Furthermore, the cardiac MRI features of DD cohort in this study were compared with those of DD in previous literature and with genetically confirmed sarcomeric HCM.

Progression of Danon disease with medical imaging: two case reports

Danon disease is a rare X-linked dominant genetic disorder caused by loss-of-function mutations in the lysosome-associated membrane protein 2 gene. Progression of Danon disease is unknown because of its rare incidence in a diverse ethnic population. We report longitudinal data from two patients who were diagnosed with Danon disease by a genetic test. The evaluation protocol included electrocardiographic monitoring, echocardiography, and magnetic resonance imaging. Progression of hypertrophic cardiomyopathy to dilated cardiomyopathy was observed in the first patient. He died from sudden cardiac arrest. The second patient is currently suffering from hypertrophic cardiomyopathy. Development of the hypertrophic phase progressing into the dilated phase in Danon disease may provide useful information for early identification and clinical decisions in patients with this disease.

Drug Development and the Use of Induced Pluripotent Stem Cell-Derived Cardiomyocytes for Disease Modeling and Drug Toxicity Screening

: Over the years, numerous groups have employed human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) as a superb human-compatible model for investigating the function and dysfunction of cardiomyocytes, drug screening and toxicity, disease modeling and for the development of novel drugs for heart diseases. In this review, we discuss the broad use of iPSC-CMs for drug development and disease modeling, in two related themes. In the first theme-drug development, adverse drug reactions, mechanisms of cardiotoxicity and the need for efficient drug screening protocols-we discuss the critical need to screen old and new drugs, the process of drug development, marketing and Adverse Drug reactions (ADRs), drug-induced cardiotoxicity, safety screening during drug development, drug development and patient-specific effect and different mechanisms of ADRs. In the second theme-using iPSC-CMs for disease modeling and developing novel drugs for heart diseases-we discuss the rationale for using iPSC-CMs and modeling acquired and inherited heart diseases with iPSC-CMs.

A case report of delayed diagnosis of danon disease: Caused by a newly recognized mutation in the lysosome-associated membrane protein-2 gene

INTRODUCTION

Danon disease is a rare X-linked dominant genetic disorder caused by defects in the lysosome-associated membrane protein 2 (LAMP2) gene. Unless treated, cardiogenic death is the main cause of mortality. This case report describes a 19-year-old man who was diagnosed with Danon disease and survived for 3 years from symptom onset to death. The mutation in his LAMP2 gene (p.Gly221Ilefs*19) had not been previously reported.

PATIENT CONCERNS

A 19-year-old man patient was hospitalized for intermittent palpitations. He had no family history of cardiomyopathy, arrhythmia, or sudden cardiac death, but his sister had died of cirrhosis at age 12 years, but the exact cause of cirrhosis was unknown.

DIAGNOSIS

Exome sequencing and Sanger sequencing identified a novel missense mutation (p.Gly221Ilefs*19) in the LAMP2 gene of the proband. This mutation was also detected in his mother, confirming the diagnosis of Danon disease.

INTERVENTIONS

The patient experienced various types of arrhythmia throughout the clinical process, including Wolff-Parkinson-White syndrome, non-sustained atrial tachycardia, atrial flutter, and third-degree atrioventricular block. He was therefore treated with cardiac ablation procedures and cardiac resynchronization therapy.

OUTCOMES

The period from the onset of symptoms to the onset of heart failure was 2 years. The patient died of cardiogenic death during the third year, at age 22 years.

LESSONS

Danon disease is a rare disease that is difficult to recognize because of its hidden early manifestations. Early identification of its clinical symptoms can lead to early diagnosis and treatment.

Cardiovascular Magnetic Resonance for the Differentiation of Left Ventricular Hypertrophy

PURPOSE OF REVIEW

Left ventricular hypertrophy (LVH) is a common presentation encountered in clinical practice with a diverse range of potential aetiologies. Differentiation of pathological from physiological hypertrophy can be challenging but is crucial for further management and prognostication. Cardiovascular magnetic resonance (CMR) with advanced myocardial tissue characterisation is a powerful tool that may help to differentiate these aetiologies in the assessment of LVH.

RECENT FINDINGS

The use of CMR for detailed morphological assessment of LVH is well described. More recently, advanced CMR techniques (late gadolinium enhancement, parametric mapping, diffusion tensor imaging, and myocardial strain) have been used. These techniques are highly promising in helping to differentiate key aetiologies of LVH and provide valuable prognostic information. Recent advancements in CMR tissue characterisation, such as parametric mapping, in combination with detailed morphological assessment and late gadolinium enhancement, provide a powerful resource that may help assess and differentiate important causes of LVH.

An unusual case of severe myocarditis in a genetic cardiomyopathy: a case report

Background

Myocarditis is an inflammatory disease of the myocardium caused by infectious pathogens, immune-mediated conditions, or toxic agents. This report explores a rare case of severe myocarditis occurring in an inherited cardiomyopathy.

Case summary

A 24-year-old female patient presented with progressing dyspnoea and chest discomfort. Echocardiography and cardiac magnetic resonance imaging revealed dilated cardiomyopathy (DCM) with severe biventricular dysfunction [left ventricle ejection fraction (LV-EF) 10%]. Myocardial inflammation was suspected due to extensive subendocardial to transmural late gadolinium enhancement. Endomyocardial biopsy (EMB) showed severe chronic lymphocytic myocarditis. As inflammatory DCM was assumed, immunosuppressive therapy with prednisolone was initiated in addition to standard heart failure therapy. Endomyocardial biopsy after 3 months showed resolving inflammation. However, a marked architectural disarray observed in all biopsies raised the suspicion of an inherited cardiomyopathy. Genetic testing revealed a de novo mutation with effect on splicing of lysosome-associated membrane protein 2, as found in Danon disease. Periodic acid–Schiff (PAS) staining confirmed a glycogen storage disorder. Immunosuppressive therapy was intensified due to reactivation of myocardial inflammation and led to improvement of LV-EF and to significant symptom relief over a 16-month follow-up period.

Discussion

This is the first report of Danon disease initially presenting as a severe myocarditis. It illustrates the clinical value of EMB for diagnosis and immunosuppressive therapy monitoring in chronic myocarditis. Increasing evidence suggests that myocardial inflammation may modify disease progression and prognosis in inherited cardiomyopathies. The causal role of cardiac protein mutations in the pathophysiology of myocarditis remains to be determined.

Clinical features and cardiovascular magnetic resonance characteristics in Danon disease

AIMS

To investigate the clinical spectrum, cardiovascular magnetic resonance imaging (cMRI) characteristics, including T1 and extracellular volume fraction, and outcomes of Danon disease to facilitate further understanding of the phenotype of patients with Danon disease.

MATERIALS AND METHODS

The study comprised six male patients 8-23 years old recruited to the study between 2014-2019. The clinical presentation, laboratory examinations, pathology/genetic analysis, electrocardiography (ECG), echocardiography, and cCMRI characteristics were summarised.

RESULTS

Five out of six patients suffered from hypertrophic cardiomyopathy (HCM) phenotype of Danon disease, while one patient had dilated cardiomyopathy (DCM) phenotype. Left ventricular (LV) and left atrial (LA) function were impaired at strain measurement. Diffuse and focal late gadolinium enhancement (LGE) were observed separately in the LV walls of three patients and right ventricular (RV) insertion points of the remaining three patients. Furthermore, values for the native T1 (mean 1313.3 ms) and extracellular volume fraction (ECV; mean 39.17%) of three patients were increased.

CONCLUSIONS

Both dilated and hypertrophic cardiomyopathy may be the phenotypes of Danon disease. Comprehensive cCMRI played a unique role in the diagnosis and grading severity and risk factors of Danon disease in vivo, especially by using robust quantitative strain analysis, T1 mapping, and further ECV calculation.

Storage diseases with hypertrophic cardiomyopathy phenotype

Never judge a book by its cover, nor assume hypertrophic cardiomyopathy (HCM) as sarcomeric, as appearances can deceive. HCM phenocopies account for a 5–10% of the cases, mainly represented by storage diseases, flagged by the increasing prevalence of senile cardiac amyloid in developing countries. Multisystemic and heterogeneous presentation of these entities is a challenge for clinicians, and time delay in diagnosis is a major concern. Promising drugs and gene-specific tailored therapies are under development, therefore, more than ever, appropriate understanding of these conditions is mandatory for adequate early treatment and counselling.

In this review, storage disorders will be classified as extracellular and intracellular deposit storage diseases, focusing our attention on the most prevalent conditions from the cardiologist’s perspective.

Multimodality Imaging in Restrictive Cardiomyopathies: An EACVI expert consensus document In collaboration with the "Working Group on myocardial and pericardial diseases" of the European Society of Cardiology Endorsed by The Indian Academy of Echocardiography

Restrictive cardiomyopathies (RCMs) are a diverse group of myocardial diseases with a wide range of aetiologies, including familial, genetic and acquired diseases and ranging from very rare to relatively frequent cardiac disorders. In all these diseases, imaging techniques play a central role. Advanced imaging techniques provide important novel data on the diagnostic and prognostic assessment of RCMs. This EACVI consensus document provides comprehensive information for the appropriateness of all non-invasive imaging techniques for the diagnosis, prognostic evaluation, and management of patients with RCM.

Left ventricular hypertrophy and cognitive function: a systematic review

Cognitive impairment is common in patients with hypertension. Left ventricular hypertrophy (LVH) is recognised as a marker of hypertension-related organ damage and is a strong predictor of coronary artery disease, heart failure and stroke. There is evidence that LVH is independently associated with cognitive impairment, even after adjustment for the presence of hypertension. We conducted a systematic review that examined cognitive impairment in adults with LVH. Independent searches were performed in Ovid MEDLINE, Ovid psycInfo and PubMed with the terms left ventricular hypertrophy and cognition. Seventy-three studies were identified when both searches were combined. After limiting the search to studies that were: (1) reported in English; (2) conducted in humans; (3) in adults aged 50 years and older; and (4) investigated the relationship between LVH and cognitive performance, nine papers were included in this systematic review. The majority of studies found an association between LVH and cognitive performance. Inspection of results indicated that individuals with LVH exhibited a lower performance in cognitive tests, when compared to individuals without LVH. Memory and executive functions were the cognitive domains that showed a specific vulnerability to the presence of LVH. A possible mechanism for the relationship between LVH and cognition is the presence of cerebral white matter damage. White matter lesions occur frequently in patients with LVH and may contribute to cognitive dysfunction. Together, the results of this review suggest that memory impairment and executive dysfunction are the cognitive domains that showed a particular association with the presence of LVH.

Imaging of Left Ventricular Hypertrophy: a Practical Utility for Differential Diagnosis and Assessment of Disease Severity

PURPOSE OF REVIEW

Left ventricular hypertrophy (LVH) is often encountered in clinical practice, and it is a risk factor for cardiac mortality and morbidity. Determination of the etiology and disease severity is important for the management of patients with LVH. The aim of this review is to show the remarkable progress in cardiac imaging and its importance in clinical practice.

RECENT FINDINGS

This review focuses on clinical features and characteristic cardiac imaging in LVH caused by various diseases including hypertension, aortic valve stenosis, hypertrophic cardiomyopathy, and secondary cardiomyopathies. The usefulness of echocardiography as a tool of general versatility including hemodynamic evaluation and the usefulness of cardiac magnetic resonance imaging for assessment of cardiac morphology and myocardial tissue characteristics of relevance for LVH are described. Imaging modalities now have central roles in the differentiation and prognostic assessment of LVH.

Infiltrative Cardiomyopathies

Infiltrative cardiomyopathies can result from a wide spectrum of both inherited and acquired conditions with varying systemic manifestations. They portend an adverse prognosis, with only a few exceptions (ie, glycogen storage disease), where early diagnosis can result in potentially curative treatment. The extent of cardiac abnormalities varies based on the degree of infiltration and results in increased ventricular wall thickness, chamber dilatation, and disruption of the conduction system. These changes often lead to the development of heart failure, atrioventricular (AV) block, and ventricular arrhythmia. Because these diseases are relatively rare, a high degree of clinical suspicion is important for diagnosis. Electrocardiography and echocardiography are helpful, but advanced techniques including cardiac magnetic resonance (CMR) and nuclear imaging are increasingly preferred. Treatment is dependent on the etiology and extent of the disease and involves medications, device therapy, and, in some cases, organ transplantation. Cardiac amyloid is the archetype of the infiltrative cardiomyopathies and is discussed in great detail in this review.

Clinical neurogenetics: neuropathic lysosomal storage disorders

The lysosomal storage disorders are a clinically heterogeneous group of inborn errors of metabolism, associated with the accumulation of incompletely degraded macromolecules within several cellular sites. Affected individuals present with a broad range of clinical problems, including hepatosplenomegaly and skeletal dysplasia. Onset of symptoms may range from birth to adulthood. Most are associated with neurologic features. Later-onset forms are often misdiagnosed as symptoms, which might include psychiatric manifestations, are slowly progressive, and may precede other neurologic or systemic features. Symptomatic care, which remains the mainstay for most subtypes, can lead to significant improvement in quality of life.

Mosaic tissue distribution of the tandem duplication of LAMP2 exons 4 and 5 demonstrates the limits of Danon disease cellular and molecular diagnostics

Alu-mediated tandem duplication of exons 4 and 5 (g.15815_22218dup6404) is a novel mutation that has been detected in the LAMP2 gene (Xq24). This exon copy number variation was found in two brothers with the typical phenotype of Danon disease, including characteristic myocardial changes on magnetic resonance imaging. The 6.4 kb duplication was identified in both boys by a combination of exon dosage qPCR analyses and duplication breakpoint/junction mapping. The rearrangement results in a plethora of abnormal LAMP2 splicing variants and also in use of likely cryptic splice sites in the 3' terminus of LAMP2 gene. Although we found minute amounts of normal LAMP2B and LAMP2A mRNAs, no protein was detectable in peripheral blood leukocytes by flow cytometry in both brothers. Uniquely, the fraction of LAMP2-deficient granulocytes (0.06%) assessed by flow cytometry in the patients' asymptomatic mother substantially differed from the random distribution of X-chromosome inactivation in her leukocytes. This discrepancy was later explained by molecular genetic methods as a consequence of mosaic distribution of the mutation in her somatic tissues. Altogether, we report a novel and mosaically distributed exon copy number rearrangement in the LAMP2 gene and comment on obstacles this genetic setup presents to the overall cellular and molecular diagnostic algorithm of Danon disease. Our observations of the mosaicism in the asymptomatic mother suggest that similarly affected females could be a potentially under-diagnosed Danon disease carrier group and that LAMP2 flow cytometry, because of its supreme sensitivity, can be an efficient method for pedigree screening.