Definition

Lysosomal storage disease is a group of disorders that affect specific enzymes in a specific location in the cell. These enzymes normally break down items for reuse in the cells. If the enzymes are missing or don't work properly, then the items can build up and become toxic. This happens in an area of the cell called lysosomes. The build up eventually leads to damage of cells and organs in the body.

There are about 50 types of lysosomal diseases. The diseases are characterized by the specific enzymes involved. Examples include:

• Fabry disease—affects the kidney, heart, and skin
• Gaucher disease —affects the spleen and bones, and causes anemia
• Hurler syndrome—affects the spleen, liver, joints, and eyes; causes intellectual disability and deafness
• Batten disease—affects the brain and eyes
• Niemann-Pick disease —affects the spleen, liver, and lungs
• Pompe disease—affects the liver, heart, and muscle tissue
• Tay-Sachs disease —affects the brain

Causes

Lysosomal storage disease is caused by a genetic problem. The genes that plan the production of the enzymes is faulty. Both parents must pass the gene on to the child in order for the disease to develop.

Genetic Material

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Risk Factors

Lysosomal storage disease is more common in families with:

• Ashkenazi Jewish, Finnish, Asian, or Dutch heritage
• A family history of the disease
• Parents that are related to each other

Symptoms

Symptoms can be severe and appear shortly after birth or mild and detected later in life. Symptoms will depend on the specific type of disease. Some common symptoms include:

• Unusual facial appearance
• Developmental delays
• Problems with the heart, liver, or kidney
• Muscle problems, usually weakness
• Seizures
• Neurologic problems, including problems with hearing or sight
• Recurrent infections or hernias
• Problems including nerve and bone pain

Diagnosis

You will be asked about your child's symptoms and medical history. A physical exam will be done. Skin and blood testing may be done to look for the specific enzyme that is causing the problem.

Other tests may include:

• MRI scan of the brain
• Tissue biopsy

Prenatal testing and newborn screening may help with early detection of some diseases.

Treatment

Treatment is focused on managing the symptoms caused by the missing enzymes. Treatment options may include:

• Dialysis —to remove substances from the blood
• Physical therapy
• Surgery
• Medication

Other treatments may include:

• Substrate synthesis inhibition therapy (SSI)—Medication that decreases the item that build up in the cells due to missing enzymes
• Enzyme replacement therapy (ERT)—Working enzymes are delivered through an IV to do the job of the defective enzymes
• Stem cell transplant— Stem cells are transplanted through IV to encourage the body to make the missing enzyme

Prevention

There are no current guidelines to prevent these disorders.