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Medicine® Printer-friendly version HMG-CoA lyase deficiency
3-hydroxy-3-methylglutaryl-CoA lyase deficiency  (often
shortened to HMG-CoA lyase deficiency) Reviewed October 2008
What is HMG-CoA lyase deficiency?  3-hydroxy-3-methylglutaryl-
CoA lyase deficiency (also known as HMG-CoA lyase deficiency) is
an uncommon inherited disorder in which the body cannot process
a particular protein building block (amino acid) called leucine.
Additionally, the disorder prevents the body from making
ketones, which are used for energy during periods without food
(fasting).  The signs and symptoms of HMG-CoA lyase deficiency
usually appear within the first year of life. The condition
causes episodes of vomiting, diarrhea, dehydration, extreme
tiredness (lethargy), and weak muscle tone (hypotonia). During
an episode, blood sugar levels can become dangerously low
(hypoglycemia), and a buildup of harmful compounds can cause the
blood to become too acidic (metabolic