Inherited Metabolic Diseases—Overview
DefinitionInherited metabolic diseases are a group of disorders that cause missing or defective enzymes. The enzyme problems can lead to:
- A build up of harmful substances that the enzymes would otherwise breakdown
- An inability to fully breakdown food for use in the cells
CausesThese diseases are caused by a problem with the genes that determine how specific enzymes are made. The genes are passed on from parent(s) to child.
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Risk FactorsInherited metabolic disease is more common in families with Ashkenazi Jewish, Finnish, or Dutch heritage. A family history increases the chance of these diseases as well.
SymptomsSymptoms can be severe and appear shortly after birth. Symptoms can also be mild and detected later in life. Tell your doctor if your child has any of these:
- Skin rash
- Recurrent infections or hernias
- Developmental delays
- Problems with hearing or sight
- Problems including pain with bones
- Problems with heart
DiagnosisThe doctor will ask 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 be done to look for any problems that may have developed. Tests may include:
- Screening tests for vision and hearing
- Eye exams
- Neuropsychological testing—measures mental function
- MRI scan
- Lumbar puncture —fluid is taken from the spine and examined
- Tissue biopsy —a sample of tissues is taken and examined
- Electromyogram (EMG)—measures electrical impulses in the muscles
- Other special tests of the heart, liver, and kidneys
TreatmentTalk with the doctor about the best treatment plan for your child. Treatment will depend on the type of condition your child has. Options may include:
NutritionDietary changes that may be required include avoiding certain foods, avoiding long periods of not eating, or taking vitamins.
Ongoing Symptom ManagementTo manage symptoms and other conditions, your child may need:
- Physical therapy
- 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.
Ongoing MonitoringFor some conditions, regular annual screening tests will be needed, such as:
PreventionThere are no current guidelines to prevent these disorders.
Children Living with Inherited Metabolic Disorders
Society for Inherited Metabolic Disorders
The Canadian Society for Mucopolysaccharide & Related Diseases
Information for Professionals. National Information Center for Metabolic Diseases (CLIMB) website. Available at: http://www.climb.org.uk/imd.html?s=information+for+professionals. Accessed August 12, 2014.
Lipid Storage Disease. National Institute of Neurological Disorders an Stroke website. Available at: http://www.ninds.nih.gov/disorders/lipid%5Fstorage%5Fdiseases/detail%5Flipid%5Fstorage%5Fdiseases.htm. Updated April 16, 2014. Accessed August 12, 2014.
- Reviewer: Michael Woods, MD
- Review Date: 08/2014
- Update Date: 06/03/2013