Metabolic Disorders

Metabolic disorders are rare genetic disorders that result from a missing or defective enzyme in the body and include organic acidemias, urea cycle defects, fatty acid oxidation defects, glycogen storage disorders, lysosomal storage disorders, and mitochondrial diseases. Symptoms of metabolic disorders vary widely and can range from mild to life-threatening.

There are hundreds of metabolic disorders. Some include:

• Familial hypercholesterolemia
• Batten disease
• Gaucher disease
• Hunter syndrome
• Krabbe disease
• Leukodystrophies
• Mitochondrial encephalopathy, lactic acidosis, stroke-like episodes (MELAS)
• Niemann-Pick
• Pelizaeus-Merzbacher
• Phenylketonuria (PKU)
• Porphyria
• Tay-Sachs disease

Symptoms

Metabolic disorders are caused by a genetic defect, sometimes inherited from the parents, that interferes with the body’s metabolism. Metabolism is the complex set of chemical reactions that your body uses to maintain life. Special enzymes break down food or certain chemicals, so your body can use or store them. When these chemical processes don't work properly due to a hormone or enzyme deficiency, a metabolic disorder occurs.

Symptoms of metabolic disorders may include:

• Abnormal odor of breath, sweat, and urine
• Somnolence (excessive sleepiness)
• Developmental delay
• Failure to thrive (in infants)
• Jaundice
• Lethargy
• Poor appetite
• Seizures
• Vomiting

Diagnosis

Sometimes, metabolic disorders are diagnosed by routine screening tests done at birth. Others are identified after a child shows symptoms of a disorder.

Treatment

Most treatable metabolic conditions require special diets. Other metabolic conditions do not have treatments yet. Care options may include genetic counseling, nutritional counseling, and supportive therapies and medication.