Metabolic Disorders

Inherited metabolic disorders, or inborn errors of metabolism, are a group of rare genetic disorders that often result in missing or defective enzymes or transport proteins, causing a block in a metabolic pathway. They are individually rare but collectively common and can present prenatally, very early after birth or at any age from infancy to adulthood. Inherited metabolic disorders can affect multiple organ systems and often cause neurologic, gastrointestinal and other complications that can have serious, sometimes life-threatening, health risks if left untreated. 

Inborn errors of metabolism can lead to impaired energy production or result in the accumulation of a variety of specific “toxic” compounds inside cells in the body, which may damage tissues and organs and cause a wide range of problems. Amino or organic acid metabolism disorders, such as phenylketonuria (PKU), maple syrup urine disease and organic acidemias, can lead to an abnormal buildup of specific amino or organic acids. Urea cycle disorders can lead to ammonia intoxication. Storage diseases often result from genetic defects in the function of peroxisomes or lysosomes (microscopic organelles that break down various molecules using enzymes) and/or a failure to convert certain substances into energy. These include lysosomal, peroxisomal and glycogen storage diseases, which, as a group, can lead to an abnormal buildup of sugars, fats, proteins and various acids inside cells.

Lysosomal storage diseases comprise a subgroup of more than 50 inherited metabolic disorders often caused by a deficient or defective lysosomal enzyme or other protein needed to metabolize lipids, carbohydrates and proteins. Clinical findings vary based on the disease, age of onset and a variety of other factors, and they often involve abnormalities of multiple organ systems, including the central nervous system, brain, liver, skin, skeleton and heart, with neurologic findings that may be progressive and disabling.  

Mitochondrial disorders represent a group of disorders resulting from a deficiency in energy production or utilization due to genetic defects in mitochondria (organelles that regulate the production of cellular energy). They often cause muscular, neurologic and cardiac problems since these organs contain high-energy tissues. Other organ systems can also be affected, leading to impaired vision and hearing, diabetes and stunted growth. Sometimes, muscle disease (myopathy) is the main manifestation of a mitochondrial disorder. 

Receiving a diagnosis of a rare metabolic disorder, or being at risk for or suspected of having one, can feel overwhelming, but learning more about the diagnosis can help you navigate treatment and care. Visit the links below to learn more about some of the different types of rare disorders, their causes, and associated symptoms as well as screening and treatment options. This list includes a selection of rare metabolic disorders. Schedule a consultation with us for diagnosis and treatment options for these or any other rare conditions.