3-Hydroxy-3-Methylglutaric Aciduria (HMG)



3-hydroxy-3-methylglutaric aciduria (HMG) is a condition in which the body is unable to break down certain proteins. People with the condition are also unable to produce ketone bodies, substances that help the body store energy. HMG can lead to a harmful amount of organic acids and toxins in the body. Early detection and treatment can often prevent the serious outcomes of this condition. Each baby with HMG has a slightly different experience. Most affected babies start to show signs of HMG between 3 months and 2 years of age. In a few cases, babies start to show signs of the condition just a few days after birth. Signs of HMG include poor appetite, sleeping longer or more often, tiredness, irritability, muscle weakness (hypotonia), vomiting, fever, diarrhea, low blood sugar (hypoglycemia), and behavior changes.  Many of these signs may occur when a baby eats foods the body cannot break down. Symptoms can be triggered by long periods of time without eating, illnesses, and infections. 

Condition Type:

Core Conditions


3-hydroxy-3-methylglutaric aciduria (HMG) is rare. There are estimated to be fewer than 100 people with HMG worldwide.

More Information for Parents:
Also known as:
  • HMG
  • HMG-CoA lyase deficiency
  • Deficiency of hydroxymethylglutaryl-CoA lyase
  • 3HMG
  • 3-hydroxy-3-methylglutaryl-coenzyme A lyase deficiency
  • Hydroxymethylglutaric aciduria
  • 3-OH 3-CH3 glutaric aciduria

Core Conditions