Danon disease (clinical case)

Background: In 1981 Morris Danon described 2 patients with severe hypertrophic cardiomyopathy as a glycogen storage disease of the heart.  Danon disease is a rare X-linked dominant genetic disorder that manifests with the clinical triad of cardiomyopathy, skeletal myopathy, and intellectual disability. It is caused by genetic mutations in the lysosome-associated membrane 2 (LAMP2) gene, with most mutations leading to an absence of LAMP2 protein.

Material: The young man at 22 years old with asthenic body type and low intellectual level; his main complaints were general weakness, heart palpitations. Family history -his mother had a pacemaker implanted at the age of 34 due to sick sinus syndrome. Father is healthy.  

Methods: EKG, EKG monitoring by Holter, doppler-echocardiography, cardiac magnetic resonance, laboratory tests, genetics test,.

Results: Biochemical tests showed that elevated level of ALT was 5,8 times higher than normal; AST - 4,8 times; The level of CFK was also increased with mostly elevation of MB fraction and the level of troponin was normal. 

EKG revealed high ECG voltage with repolarization abnormalities, Wolff-Parkinson-White (WPW) syndrome (pre-excitation syndrome). In EKG monitoring by Holter were found 160 episodes of supraventricular tachycardia, 1119 extrasystoles, maximum heart rate -122 bit/min. Echocardiogram and cardiac magnetic resonance imaging showed severe left ventricular hypertrophy: LV myocardial mass index -246g/m2, wall thickness parameter-0,61; EFLV-60%, GLSmean= -16,4. Retinal examination showed changes in retinal pigment.

Genetic test – a mutation c.928G>A was detected in exon 7 of the LAMP2 gene: x-linked dominant inheritance pattern. The mother was a carrier of the mutant gene, which she passed on to her son.

?onclusions: An x-linked dominant inheritance pattern in conjunction with hypertrophic cardiomyopathy in young male, skeletal myopathy, retinopathy, intellectual disability and immunohistochemistry with LAMP2 protein deficiency strongly suggests Danon disease.

PhD, professor Saule Urazalina is a cardiologist specializing in functional methods of diagnostics as EKG, Echocardiography, EKG monitoring by Holter. She graduated from the 1-st Moscow medical university named after I.M. Sechenov. She engaged in scientific work at the Russian cardiology research and production complex and defended doctoral dissertation on the topic of subclinical atherosclerosis. Dr. Saule Urazalina completed the clinical-theoretical program in the modern methods of echocardiography in Tel-Aviv Sourasky medical center affiliated to Tel-Aviv university. She is currently the professor of cardiological department in Kazakh National Medical University named after S.D Asfendiarov.