3-hydroxy-3-methylglutaryl-CoA lyase deficiency (also referred to as HMG-CoA lyase deficiency) is an uncommon inherited disorder in which the body cannot properly process a particular amino acid (a building block of proteins). Additionally, the disorder prevents the body from making ketones, which are used for energy during fasting (periods without food). This disorder usually appears within the first year of life. The signs and symptoms of HMG-CoA lyase deficiency include vomiting, dehydration, extreme tiredness (lethargy), convulsions, and coma. When episodes occur in an infant or child, blood sugar becomes extremely low (hypoglycemia), and harmful compounds can build up and cause the blood to become too acidic (metabolic acidosis). These episodes are often triggered by an infection, fasting, strenuous exercise, or sometimes other types of stress.
