HMG CoA lyase deficiency

Title

Other Names:

3-hydroxy-3-methylglutaryl-CoA lyase deficiency; Defect in leucine metabolism; HMG-CoA lyase deficiency; 3-hydroxy-3-methylglutaryl-CoA lyase deficiency; Defect in leucine metabolism; HMG-CoA lyase deficiency; 3-hydroxy-3-methylglutaric aciduria; Hydroxymethylglutaric aciduria See More

Categories:

Congenital and Genetic Diseases; Metabolic disorders; Newborn Screening

Summary Summary

HMG CoA lyase deficiency is an inherited disorder in which the body cannot process a protein called leucine or make ketones. Ketones are used for energy during periods of fasting. The signs and symptoms of condition usually appear within the first year of life and include 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 acidosis). If untreated, the disorder can lead to breathing problems, convulsions, coma, and death. Episodes are often triggered by an infection, fasting, strenuous exercise, or other types of stress. Mutations in the HMGCL gene cause HMG-CoA lyase deficiency, and this condition is inherited in an autosomal recessive pattern.^[1]^[2] Treatment usually involves a team of specialists including a metabolics and/or genetics specialist and a dietician and may include avoidance of fasting, a low leucine diet, and supplementation with L-carnitine.^[3]

Last updated: 1/19/2017

Symptoms Symptoms

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 one of these episodes, blood sugar levels can become dangerously low (hypoglycemia), and a buildup of harmful compounds can cause the blood to become too acidic (metabolic acidosis). If untreated, the disorder can lead to breathing problems, convulsions (seizures), coma, and death. Episodes are often triggered by an infection, fasting (not eating enough), strenuous exercise, or other types of stress.^[1]

Last updated: 1/19/2017

The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.

Signs and Symptoms	Approximate number of patients (when available)
3-Methylglutaric aciduria	-
Autosomal recessive inheritance	-
Coma	-
Death in childhood	-
Decreased plasma carnitine	-
Excessive daytime somnolence	-
Fever	-
Glutaric aciduria	-
Hepatomegaly	-
Hyperammonemia	-
Hypoglycemia	-
Metabolic acidosis	-

Last updated: 9/1/2017

Inheritance Inheritance

HMG CoA lyase deficiency is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene (and are referred to as carriers), but they typically do not show signs and symptoms of the condition. When parents who are both carriers of an autosomal recessive condition have a child, there is a 1 in 4 (25%) chance for each child to have the condition, a 1 in 2 (50%) chance for each child to be a carrier like each of the parents, and a 1 in 4 (25%) chance for the child not to have the condition and not be a carrier.^[1]

Last updated: 1/19/2017

Diagnosis Diagnosis

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Newborn Screening

The Newborn Screening Coding and Terminology Guide has information on the standard codes used for newborn screening tests. Using these standards helps compare data across different laboratories. This resource was created by the National Library of Medicine.
An ACTion (ACT) sheet is available for this condition that describes the short-term actions a health professional should follow when an infant has a positive newborn screening result. ACT sheets were developed by experts in collaboration with the American College of Medical Genetics.
An Algorithm flowchart is available for this condition for determining the final diagnosis in an infant with a positive newborn screening result. Algorithms are developed by experts in collaboration with the American College of Medical Genetics.

Treatment Treatment

The resources below provide information about treatment options for this condition. If you have questions about which treatment is right for you, talk to your healthcare professional.

Management Guidelines

Orphanet Emergency Guidelines is an article which is expert-authored and peer-reviewed that is intended to guide health care professionals in emergency situations involving this condition.

Do you have updated information on this condition? Let us know.

Organizations Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

FOD (Fatty Oxidation Disorder) Family Support Group
P.O. Box 54
Okemos, MI 48805-0054
Telephone: 517-381-1940
Fax: 866-290-5206
E-mail: deb@fodsupport.org
Website: http://www.fodsupport.org
Genetic Metabolic Dietitians International
P.O. Box 33985
Fort Worth, TX 76162
Website: http://www.gmdi.org/
Organic Acidemia Association
9040 Duluth Street
Golden Valley, MN 55427
Telephone: 763-559-1797
Fax: 866-539-4060
E-mail: mkstagni@gmail.com
Website: http://www.oaanews.org/

Parent Matching Organizations

The Organic Acidemia Association helps connect the parents of children with organic acidemias.

Do you know of an organization? Send us your suggestions.

Living With Living With

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Genetics Resources

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by GeneTests, the American College of Medical Genetics, and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.

Learn More Learn More

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

Genetics Home Reference (GHR) contains information on HMG CoA lyase deficiency. This website is maintained by the National Library of Medicine.
The Screening, Technology And Research in Genetics (STAR-G) Project has a fact sheet on this condition, which was written specifically for families that have received a diagnosis as a result of newborn screening. This fact sheet provides general information about the condition and answers questions that are of particular concern to parents.

In-Depth Information

The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
The New England Consortium of Metabolic Program has written medical guidelines called acute care protocols for HMG CoA lyase deficiency for health care professionals.
Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine.
Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
PubMed is a searchable database of medical literature and lists journal articles that discuss HMG CoA lyase deficiency. Click on the link to view a sample search on this topic.

News & Events News & Events

News

Don’t Miss the NCATS Toolkit for Patient-Focused Therapy Development Event
August 31, 2017
Funding Opportunities Now Available for the Undiagnosed Diseases Network (UDN) Phase II
August 30, 2017
IRDiRC Goals 2017-2027: New Rare Disease Research Goals for the Next Decade
August 10, 2017

Other Conferences

The International Network for Fatty Acid Oxidation Research and Management (INFORM) has been formed in order to promote research and discussion into the cause, diagnosis, and management of inborn errors of fatty acid oxidation. INFORM will sponsor an inaugural symposium to be held on September 6, 2014 in Innsbruck, Austria following SSIEM, with annual meetings thereafter. The Network will provide a collaborative framework for ongoing communication and research between the members.

GARD Answers GARD Answers

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

My daughter has been diagnosed with this condition. I have low platelet and white blood cell counts and have been told my marrow does not properly store iron. Is it possible that I have the condition also, and may not be just a carrier? See answer
Are there any active protocols researching this disorder? We would like to make a donation for research. See answer

Have a question? Contact a GARD Information Specialist.

References References

3-hydroxy-3-methylglutaryl-coenzyme A lyase deficiency. Genetics Home Reference. October 2008; https://ghr.nlm.nih.gov/condition/3-hydroxy-3-methylglutaryl-coa-lyase-deficiency.
Bandeira A, Vilarinho L. 3-hydroxy-3-methylglutaric aciduria. Orphanet. August 2014; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=20.
Organic Acid Oxidation Disorders: 3-hydroxy-3-methylglutaryl-CoA lyase deficiency. Screening, Technology and Research in Genetics (STAR-G). April 20, 2016; http://www.newbornscreening.info/Parents/organicaciddisorders/HMGCoA.html#4.

Do you know of a review article? Send us your suggestions.