Danon disease in children: view of a pediatric cardiologist

Abstract

Danon disease is a rare hereditary disease with predominant damage to the heart and skeletal muscles. Danon disease is referred to lysosomal storage disorders with severe, progressive course and it often leads to an early mortality. The main cause of Danon disease is the mutations in the LAMP2 gene in the Xq24–q25 chromosome region. Danon disease has X-linked dominant nature of inheritance; women have a milder phenotype with older heart damage. For the first time the disease was described in boys with cardiomyopathy, severe skeletal myopathy and intellectual deficiency. The article presents up-to-date review on Danon disease and case reports of the cardiology department of the National Medical Research Center for Children’s Health, where 5 male patients were observed from 2014 to 2020, and the average age at diagnosis – 13,2 years. During the lab examination three patients demonstrated a significant increase of the heart failure marker (NT-proBNP) – more than 5 thousand pg/ml, the intracellular enzymes was more than 2,5 norms in 4 patients. The Wolff–Parkinson–White phenomenon is recorded in all patients on the ECG. Echocardiography in one patient showed a rare combination of myocardial hypertrophy and non-compact left ventricular myocardium. 2 patients had a combination of hypertrophic and dilated phenotypes with a reduced ejection fraction on Echo and severe myocardial fibrosis on MRI of the heart, which clinically manifested with chronic heart failure refractory to drug therapy, which required heart transplantation.