Definition

Lysosomal storage disease is a group of disorders that affect specific enzymes in a specific location. 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 over 40 different types of lysosomal diseases. The diseases are characterized by the specific enzymes involved. Examples include:

• Fabry Morquio 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
• Maroteaux-Larny disease—affects the skin, bones, liver, and spleen
• 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.

Risk Factors

Lysosomal storage disease is more common in families with Ashkenazi Jewish, Finnish, or Dutch heritage. A family history increases the chance of the disease as well.

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:

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

These symptoms may be caused by other conditions. If your child has any of these symptoms, talk to the doctor right away.

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. Specific treatment depends on the enzyme defect that your child has but 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.

National MPS Society http://www.mpssociety.org

Health Canada http://www.hc-sc.gc.ca

Lipid storage disease fact sheet. National Institute of Neurological Disorders an Stroke website. Available at:
http://www.ninds.nih.gov/disorders/lipid_storage_diseases/detail_lipid_storage_diseases.htm
Updated January 13, 2015. Accessed August 11, 2015.

Lysosomal storage disorders. National Organization of Rare Disorders website. Available at: https://www.rarediseases.org/rare-disease-information/rare-diseases/byID/1132/viewFullReport. Updated March 14, 2008. Accessed August 11, 2015.

Marsden D, Levy H. Newborn screening of lysosomal storage disorders. Clin Chem. 2010;56(7):1079.

Wynn RF, Wraith JE, Mercer J, et al. Improved metabolic correction in patients with lysosomal storage disease treated with hematopoietic stem cell transplant compared with enzyme replacement therapy. J Pediatr. 2009;154(4):609.