Danon Disease
This is a rare genetic disease, inherited in an X-linked dominant pattern, affecting both sexes. It is caused by mutations in the gene located on the X chromosome expressing the LAMP2 protein, which can be either inherited or sporadic, creating new cases in a family.
Symptoms do not manifest at birth, unless it is ascertained early in the laboratory due to family history.
Symptoms
Males: There is a cardiomyopathy that can develop into hypertrophic cardiomyopathy and more rarely diastolic, causing obvious fatigue and respiratory problems. It may evolve so that heart transplantation is needed or even death in the second or third decade of life. In addition, skeletal myopathy is present, mainly in back, shoulder, neck and upper leg muscles, causing difficulty in walking or stair climbing, difficulty in raising hands above head or in seat effort. There may be mental difficulties ranging from learning difficulties to mental retardation. But usually people succeed in reading, working, relationship development and independent living. In addition, there is a vision problem (retinopathy).
Females: Mild symptoms, which occur after adulthood. In severe cases, there are heart problems (hypertrophic or diastolic cardiomyopathy), which may even require heart transplantation, muscle weakness and vision problems. Intellectual competence is normal, although there is not enough relevant information in literature.
Generally, there may be arrhythmias, and less frequently there may be problems with the liver and lungs, as well as some psychiatric disorders such as psychosis, depression, which is not clear if they are directly related to the disease itself.
Diagnosis
- Family history.
- Muscle biopsy.
- Genetic tests.
- Blood tests for CK enzyme determination.
- Electrocardiogram – ultrasound – heart MRI.
Management
There is no cure for Danon’s disease but its treatment is symptomatic and requires coordinated care from many medical specialists and not only, cardiologist, neurologist, ophthalmologist, geneticist, genetic counselor, physiotherapist, special education teacher.
This requires specific medication for heart problems, possibly using pacemaker and heart transplantation, monitoring of neurological and ocular function, appropriate exercises and the ability to educate, which contributes to the cognitive problems.
To follow-up clinical trials on the disease visit: https://clinicaltrials.gov/ct2/home
References
- NORD (National Organization for Rare Disorders), rare diseases, Danon disease, https://rarediseases.org/rare-diseases/danon-disease/
- T. J. Rowland, M. E. Sweet, L. Mestroni, M. R. G. Taylor, Danon disease – dysregulation of autophagy in a multisystem disorder with cardiomyopathy, 2016, 129, p. 2135-2143.
- R. S. D’souza, C. Levandowski, D. Slavov, S. L. Graw, L. A. Allen, E. Adler, L. Mestroni, M. R.G. Taylor, Danon Disease: Clinical Features, Evaluation, and Management, Circ Heart Fail. 2014, 7, (5), p. 843–849.