Inherited Metabolic Disorders
Symptoms of Inherited Metabolic Disorders
The symptoms of genetic metabolic disorders vary widely depending on the metabolism problem present. Some symptoms of inherited metabolic disorders include:
- Poor appetite
- Abdominal pain
- Failure to gain weight or grow
- Developmental delay
- Abnormal odor of urine, breath, sweat, or saliva
The symptoms may come on suddenly or progress slowly. Symptoms may be brought on by foods, medications, dehydration, minor illnesses, or other factors. Symptoms appear within a few weeks after birth in many conditions. Other inherited metabolic disorders may take years for symptoms to develop.
Diagnosis of Inherited Metabolic Disorders
Inherited metabolic disorders are present at birth, and some are detected by routine screening. All 50 states screen newborns for phenylketonuria (PKU). Most states also test newborns for galactosemia. However, no state tests babies for all known inherited metabolic disorders.
Improved testing technology is leading many states to expand newborn screening for genetic metabolic disorders. The National Newborn Screening and Genetics Resources Center provides information on each state's screening practices.
If an inherited metabolic disorder is not detected at birth, it is often not diagnosed until symptoms appear. Once symptoms develop, specific blood or DNA tests are available to diagnose most genetic metabolic disorders. Referral to a specialized center (usually at a university) increases the chances of a correct diagnosis.
Treatment of Inherited Metabolic Disorders
Limited treatments are available for inherited metabolic disorders. The essential genetic defect causing the condition can't be corrected with current technology. Instead, treatments try to work around the problem with metabolism.
Treatments for genetic metabolic disorders follow a few general principles:
- Reduce or eliminate intake of any food or drug that can't be metabolized properly.
- Replace the enzyme or other chemical that is missing or inactive, to restore metabolism to as close to normal as possible.
- Remove toxic products of metabolism that accumulate due to the metabolic disorder.
Treatment may include such measures as:
- Special diets that eliminate certain nutrients
- Taking enzyme replacements, or other supplements that support metabolism
- Treating the blood with chemicals to detoxify dangerous metabolic by-products