Lysosomal Storage Disease
(Glycoprotein Storage Diseases; Mucopolysaccharidoses; MPS)
Definition
Lysosomes are structures in the cells of the body. These structures carry important enzymes (proteins) that break down and eliminate cell waste. Lysosomal storage disease refers to a group of disorders that affect this process. It occurs when a specific enzyme in the body is missing or defective. The missing or defective enzyme is not able to help eliminate unwanted substances in the cells. These substances build up in the body. They impair organ function.
There are over 40 different types of lysosomal diseases characterized by the specific enzyme deficiency, such as:
- Fabry Morquio’s disease—affects the kidney, heart, and skin
-
Gaucher disease
—affects the spleen and bones, and causes anemia
- Hurler’s 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
These disorders are caused by problems in the genetic code that create the enzyme defect.
Risk Factors
Risk factors include:
- Family history
- Certain ethnic backgrounds (Ashkenazi Jewish, Finnish, Dutch)
Symptoms
Symptoms can be severe and appear shortly after birth. Symptoms can also be mild and detected later in life. Tell the doctor if your child has any of these:
- Distorted facial features
- Enlarged tongue
- Cloudy eyes
- Purple-blue skin rash
- Swollen abdomen
- Skeletal deformities
- Short stature
- Lack of muscle control
- Decreased motor skills
These symptoms may be caused by other conditions. If your child has any of these symptoms, talk to the doctor right away.
Diagnosis
The doctor will:
- Ask about your child’s symptoms and medical history
- Do a physical exam
- Work with specialists to diagnose the condition
-
Order tests, such as:
- Enzyme testing (skin, blood, urine)
- MRI scan
—a test that uses magnetic waves to make pictures of structures inside the brain
-
Tissue
biopsy
—sample is taken from the body and tested
Before your baby is born, prenatal tests can check for diseases.
Treatment
Talk with the doctor about the best treatment plan for you. Treatment depends on the enzyme defect that your child has. Treatment options may include:
Ongoing Symptom Management
To manage symptoms of lysosomal storage diseases, your child may need:
-
Dialysis
- Physical therapy
- Surgery
- Medicines
Substrate Synthesis Inhibition Therapy (SSI)
This is a medicine given to help the body make less cell waste.
Enzyme Replacement Therapy (ERT)
Working enzymes are delivered through an IV (needle in the vein). These new enzymes will do the job of the defective enzymes.
Stem Cell Transplant
Healthy
stem cells
are transplanted into your child. This may help his body make the missing enzyme.
Prevention
There is no way to prevent these kinds of disorders. Prenatal testing and newborn screening may help with early detection.
RESOURCES
Lysosomal Disease Network
http://www.lysosomaldiseasenetwork.org/
National MPS Society
http://www.mpssociety.org/
CANADIAN RESOURCES
Canadian Society for Mucopolysaccharide & Related Diseases
http://www.mpssociety.ca/
Health Canada
http://www.hc-sc.gc.ca/index%5Fe.html/
References
Badash M. Glycogen storage diseases. EBSCO Patient Education Reference Center website. Available at:
http://www.ebscohost.com/thisTopic.php?marketID=16&topicID=1034
. Updated May 28, 2010. Accessed August 6, 2010.
Cedars Sinai. Lysosomal storage disease program. Cedars Sinai website. Available at:
http://www.cedars-sinai.edu/Patients/Programs-and-Services/Lysosomal-Storage-Disease-Program/
. Accessed August 6, 2010.
Lysosomal Disease Network website. Available at:
http://www.lysosomaldiseasenetwork.org/
. Accessed August 6, 2010.
Lysosomal Learning. Genzyme. Lysosomal Learning website. Available at:
http://www.lysosomallearning.com/patient/about/lsd%5Fpt%5Fabt%5Fliving.asp
. Accessed August 9, 2010.
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.
Wynn RF, Wraith JE, Mercer J, et al. What is known. International Advocate for Glycoprotein Storage Diseases (New Zealand) website. Available at:
http://www.ismrd.org/the%5Fdiseases/what%5Fis%5Fknown
. Accessed August 6, 2010.