Which are the symptoms of Danon disease?

Symptoms of Danon Disease

Danon disease is a rare genetic disorder that primarily affects the heart, skeletal muscles, and the brain. It is caused by mutations in the LAMP2 gene, which is responsible for producing a protein called lysosome-associated membrane protein 2. This protein plays a crucial role in the functioning of lysosomes, which are responsible for breaking down waste materials within cells.

Cardiac Symptoms:

One of the hallmark features of Danon disease is the presence of severe cardiac abnormalities. These abnormalities can manifest in various ways, including:

• Hypertrophic cardiomyopathy: This is a condition characterized by the thickening of the heart muscle, particularly the left ventricle. It can lead to symptoms such as shortness of breath, chest pain, fatigue, and an irregular heartbeat.


• Heart failure: Due to the progressive deterioration of cardiac function, individuals with Danon disease may develop heart failure. Symptoms of heart failure include fluid retention, swelling in the legs and ankles, fatigue, and difficulty breathing.


• Arrhythmias: Irregular heart rhythms, such as atrial fibrillation or ventricular arrhythmias, can occur in individuals with Danon disease. These abnormal heart rhythms can lead to palpitations, dizziness, fainting, or even sudden cardiac arrest.

Muscular Symptoms:

In addition to cardiac involvement, Danon disease also affects skeletal muscles, leading to various muscular symptoms:

• Muscle weakness: Progressive muscle weakness is a common symptom of Danon disease. It typically starts in the proximal muscles, such as the shoulders and hips, and gradually affects other muscle groups. This weakness can impact mobility and daily activities.


• Difficulty with motor skills: Individuals with Danon disease may experience difficulties with coordination, balance, and fine motor skills. This can manifest as clumsiness, difficulty walking, or trouble with tasks requiring precise movements.


• Muscle cramps: Muscle cramps and spasms are common in Danon disease. These can be painful and occur spontaneously or with physical activity.

Neurological Symptoms:

While the primary manifestations of Danon disease are cardiac and muscular, some individuals may also experience neurological symptoms:

• Cognitive impairment: Danon disease can lead to intellectual disability, learning difficulties, and impaired cognitive function. This can range from mild to severe and may affect memory, attention, and problem-solving abilities.


• Behavioral changes: Some individuals with Danon disease may exhibit behavioral changes, including aggression, impulsivity, and hyperactivity.


• Seizures: Epileptic seizures can occur in individuals with Danon disease, although they are less common compared to other symptoms.

Other Symptoms:

There are several other symptoms that can occur in individuals with Danon disease:

• Growth delay: Children with Danon disease may experience delayed growth and development.


• Visual abnormalities: Some individuals may have vision problems, such as retinal dystrophy or cataracts.


• Liver involvement: In rare cases, Danon disease can affect liver function, leading to hepatomegaly (enlarged liver) or abnormal liver enzymes.

It is important to note that the severity and progression of symptoms can vary widely among individuals with Danon disease. Some individuals may have mild symptoms and a relatively stable disease course, while others may experience rapid deterioration and life-threatening complications.