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Reviewed October 2008

What is the official name of the HMGCL gene?

The official name of this gene is “3-hydroxymethyl-3-methylglutaryl-CoA lyase.”

HMGCL is the gene's official symbol. The HMGCL gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the HMGCL gene?

The HMGCL gene provides instructions for making an enzyme called 3-hydroxymethyl-3-methylglutaryl-CoA lyase (HMG-CoA lyase). This enzyme is found in mitochondria, which are the energy-producing centers inside cells. HMG-CoA lyase plays a critical role in breaking down proteins and fats from the diet. Specifically, it is responsible for processing leucine, a protein building block (amino acid) that is part of many proteins. HMG-CoA lyase also produces ketones during the breakdown of fats. Ketones are compounds that certain organs and tissues, particularly the brain, use for energy when the simple sugar glucose is not available. For example, ketones are important sources of energy during periods of fasting.

How are changes in the HMGCL gene related to health conditions?

3-hydroxy-3-methylglutaryl-CoA lyase deficiency - caused by mutations in the HMGCL gene

More than 25 mutations in the HMGCL gene have been identified in people with 3-hydroxymethyl-3-methylglutaryl-CoA lyase deficiency (also called HMG-CoA lyase deficiency). Most of these mutations change single amino acids in the HMG-CoA lyase enzyme. For example, the most common mutation in the Saudi Arabian population replaces the amino acid arginine with the amino acid glutamine at position 41 (written as Arg41Gln or R41Q). Other HMGCL mutations result in the production of an abnormally short enzyme that is missing critical segments.

If a mutation reduces or eliminates the activity of HMG-CoA lyase, the body is unable to process leucine or make ketones properly. When leucine is not processed normally, chemical byproducts called organic acids can build up and make the blood too acidic (metabolic acidosis). A shortage of ketones can cause blood sugar levels to become dangerously low (hypoglycemia). The effects of metabolic acidosis and hypoglycemia can damage cells, particularly in the brain, resulting in serious illness in children with HMG-CoA lyase deficiency.

Where is the HMGCL gene located?

Cytogenetic Location: 1p36.1-p35

Molecular Location on chromosome 1: base pairs 23,801,877 to 23,825,459

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

The HMGCL gene is located on the short (p) arm of chromosome 1 between positions 36.1 and 35.

The HMGCL gene is located on the short (p) arm of chromosome 1 between positions 36.1 and 35.

More precisely, the HMGCL gene is located from base pair 23,801,877 to base pair 23,825,459 on chromosome 1.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about HMGCL?

You and your healthcare professional may find the following resources about HMGCL helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the HMGCL gene or gene products?

  • 3-hydroxy-3-methylglutarate-CoA lyase
  • 3-hydroxy-3-methylglutaryl-Coenzyme A lyase
  • 3-hydroxymethyl-3-methylglutaryl-Coenzyme A lyase
  • HL
  • HMG-CoA lyase

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding HMGCL?

acidosis ; acids ; amino acid ; arginine ; breakdown ; CoA ; coenzyme A ; deficiency ; enzyme ; fasting ; gene ; glucose ; glutamine ; hypoglycemia ; leucine ; mitochondria ; mutation ; population ; protein ; simple sugar

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References (9 links)


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.

Reviewed: October 2008
Published: February 8, 2016