Overview of fatty acid and glycerol metabolism disorders

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Fatty acids are the preferred energy source for the heart and an important energy source for skeletal muscle during prolonged exertion. Also, during fasting, the bulk of the body’s energy needs must be supplied by fat metabolism. Using fat as an energy source requires catabolizing adipose tissue into free fatty acid and glycerol. The free fatty acid is metabolized in the liver and peripheral tissue via beta-oxidation into acetyl CoA; the glycerol is used by the liver for triglyceride synthesis or for gluconeogenesis. Carnitine is required for long-chain fatty acid oxidation. Carnitine deficiencies can be primary or secondary. Secondary carnitine deficiency is a secondary biochemical feature of many organic acidemias and fatty acid oxidation defects.
There are a number of other disorders of fatty acid and glycerol metabolism, including those involving

Fatty acid transport and mitochondrial oxidation
Glycerol
Ketones
Peroxisome biogenesis and very long-chain fatty acids
Other disorders of fat metabolism

Also see Approach to the Patient With a Suspected Inherited Disorder of Metabolism.