Question: What is (are) Danon disease ?
Answer: Danon disease is a type of lysosomal storage disorder. Lysosomes are compartments within the cell that use enzymes to break down large molecules into smaller ones that the cell can use. In Danon disease there is a defect in the wall (membrane) of the lysosome. The defect is caused by mutations in the LAMP2 gene. Danon disease is chiefly characterized by cardiomyopathy (heart disease), although other signs and symptoms may occur as well. Danon disease is inherited in an X-linked fashion, as a result males tend to be more severely affected than females. Females who carry the LAMP2 gene mutation may or may not develop signs and symptoms.
Source: GARD

Question: What are the symptoms of Danon disease ?
Answer: What are the signs and symptoms of Danon disease? Danon disease is characterized by cardiomyopathy. Cardiomyopathy causes the heart muscle to enlarge or become thicker and more rigid than normal. This may make the heart less able to pump blood through the body and can cause serious complications, including sudden death. People with danon disease may also manifest with high levels of serum creatine kinase, eye/vision abnormalities, or Wolff-Parkinson-White syndrome. Wolff-Parkinson-White syndrome is a condition characterized by abnormal electrical pathways in the heart that cause a disruption of the heart's normal rhythm (arrhythmia). Men with Danon disease tend to develop cardiomyopathy prior to the age of 20, and sometimes in early childhood. Women with Danon disease tend to develop cardiomyopathy later in adulthood, however cases of cardiomyopathy in young girls have been reported in the medical literature. Some women who carry LAMP2 gene mutation never develop any or only very minor symptoms. The following additional signs and symptoms are variably present in people with Danon disease: Learning and development (primarily reported in males, however there has been at least one report of an affected female) Mild intellectual ability Mental retardation Attention deficit disorder Skeletal muscle Exercise intolerance Muscle weakness Eye and vision Peripheral pigmentary retinopathy Lens changes Nearsightedness Abnormal visual fields Signs and symptoms of Danon disease can be very similar to those of hypertrophic cardiomyopathy, even though the underlying disease process differs. You can find detailed information on hypertrophic cardiomyopathy, which includes a brief description of Danon disease, by visiting the following link to GeneReviews. http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=hyper-card The Human Phenotype Ontology provides the following list of signs and symptoms for Danon disease. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Cognitive impairment 90% Gait disturbance 90% Hypertrophic cardiomyopathy 90% Muscle weakness 90% Sudden cardiac death 90% Intellectual disability 70% Arrhythmia - Cardiomegaly - Dilated cardiomyopathy - Elevated serum creatine phosphokinase - EMG: myopathic abnormalities - Exercise intolerance - Exercise-induced muscle cramps - Generalized amyotrophy - Hypokinesia - Myocardial fibrosis - Myocardial necrosis - Pes cavus - Phenotypic variability - Proximal muscle weakness - Visual impairment - Wolff-Parkinson-White syndrome - X-linked dominant inheritance - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD

Question: What causes Danon disease ?
Answer: What causes Danon disease? Danon disease is caused by mutation in the LAMP2 gene. LAMP2 stands for lysosomal-associated membrane protein 2.
Source: GARD

Question: Is Danon disease inherited ?
Answer: How is Danon disease inherited? Dannon disease is inherited in an X-linked fashion. Click here to visit the Centre for Genetics Education Web site to learn more about X linked inheritance.
Source: GARD

Question: How to diagnose Danon disease ?
Answer: Is genetic testing available for Danon disease? Yes. GeneTests lists laboratories offering clinical genetic testing for Danon disease. Clinical genetic tests are ordered to help diagnose a person or family and to aid in decisions regarding medical care or reproductive issues. Talk to your health care provider or a genetic professional to learn more about your testing options. Click on the link above to view a list of testing laboratories.
Source: GARD

Question: What are the treatments for Danon disease ?
Answer: How might the cardiomyopathy in Danon disease be treated? Because Danon disease can be associated with rapidly progressive cardiomyopathy and sudden death, careful monitoring of heart disease is required. Aggressive interventions may be recommended for people showing signs of progressive heart failure (e.g., early intervention with heart transplantation or implantable cardioverter-defibrillator). However, the severity of cardiomyopathy does vary, particularly in females. Management will depend on the presence and severity of the heart disease, and will be tailored to the needs of the patient.
Source: GARD