Are there specific dietary supplements or foods that help prevent metabolic crises?

diet rich in medium‑chain triglycerides (MCT oil) provides an alternative energy source that bypasses the defective β‑oxidation step. Ensure adequate protein and complex carbohydrates at each meal. Some clinicians add carnitine supplements if levels are low, but this should be guided by laboratory testing and a metabolic specialist.

What fasting schedule is safe for a child diagnosed with this deficiency?

void any intentional fasting longer than 4–6 hours. Offer regular meals and snacks every 3–4 hours, including a bedtime snack with complex carbohydrates and protein. During illness, increase carbohydrate intake (e.g., glucose‑containing oral rehydration solution) and consider a hospital‑based glucose infusion if the child cannot eat.

How can I differentiate a hypoglycemic episode caused by this disorder from other causes?

In this deficiency, low blood sugar often occurs after a short fast or during a viral illness and is accompanied by elevated insulin levels (hyperinsulinemia) and low free fatty acids. A rapid bedside glucose check will confirm hypoglycemia; a simultaneous insulin and free‑fatty‑acid panel drawn during the episode can help distinguish it from glycogen‑storage diseases, which typically show low insulin.

What should I do if my child develops a fever or viral illness that could trigger a metabolic decompensation?

Treat the illness aggressively: maintain hydration with glucose‑containing fluids, keep caloric intake high, and monitor blood glucose every 4–6 hours. If glucose falls below 70 mg/dL, give a rapid‑acting carbohydrate (e.g., 10 % dextrose gel or juice) and contact your metabolic team. In severe cases, emergency intravenous dextrose (10 % or higher) may be required to prevent coma.

3-hydroxyacyl-CoA dehydrogenase deficiency

3-hydroxyacyl-CoA dehydrogenase deficiency is an inherited condition that prevents the body from converting certain fats to energy, particularly during prolonged periods without food (fasting). Initial signs and symptoms of this disorder typically occur during infancy or early childhood.

Overview

3-hydroxyacyl-CoA dehydrogenase deficiency is an inherited condition that prevents the body from converting certain fats to energy, particularly during prolonged periods without food (fasting).

Initial signs and symptoms of this disorder typically occur during infancy or early childhood and can include poor appetite, vomiting, diarrhea, and lack of energy (lethargy). Affected individuals can also have muscle weakness (hypotonia), problems, low blood glucose (hypoglycemia), and abnormally high levels of insulin (hyperinsulinism). controls the amount of glucose that moves from the blood into cells for conversion to energy. Individuals with 3-hydroxyacyl-CoA dehydrogenase deficiency are also at risk for complications such as seizures, life-threatening and problems, coma, and sudden death. This condition may explain some cases of sudden infant death syndrome (SIDS), which is defined as unexplained death in babies younger than 1 year.

Problems related to 3-hydroxyacyl-CoA dehydrogenase deficiency can be triggered by periods of fasting or by illnesses such as viral infections. This disorder is sometimes mistaken for Reye syndrome, a severe disorder that may develop in children while they appear to be recovering from viral infections such as chicken pox or flu. Most cases of Reye syndrome are associated with the use of aspirin during these viral infections.

Frequency

The exact incidence of 3-hydroxyacyl-CoA dehydrogenase deficiency is unknown; it has been reported in only a small number of people worldwide.

Causes & Risk Factors

Mutations in the HADH gene cause 3-hydroxyacyl-CoA dehydrogenase deficiency. The HADH gene provides instructions for making an enzyme called 3-hydroxyacyl-CoA dehydrogenase.

Normally, through a process called fatty acid oxidation, several enzymes work in a step-wise fashion to break down (metabolize) fats and convert them to energy. The 3-hydroxyacyl-CoA dehydrogenase enzyme is required for a step that metabolizes groups of fats called medium-chain fatty acids and short-chain fatty acids.

Mutations in the HADH gene lead to a shortage of 3-hydroxyacyl-CoA dehydrogenase. Medium-chain and short-chain fatty acids cannot be metabolized properly without sufficient levels of this enzyme. As a result, these fatty acids are not converted to energy, which can lead to characteristic features of 3-hydroxyacyl-CoA dehydrogenase deficiency, such as lethargy and hypoglycemia. Medium-chain and short-chain fatty acids that are not broken down can build up in tissues and damage the , , and , causing serious complications.

Conditions that disrupt the metabolism of fatty acids, including 3-hydroxyacyl-CoA dehydrogenase deficiency, are known as fatty acid oxidation disorders.

Learn more about the gene associated with 3-hydroxyacyl-CoA dehydrogenase deficiency

HADH

Inheritance

This condition 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, but they typically do not show signs and symptoms of the condition.

Other Names

3-alpha-hydroxyacyl-coenzyme A dehydrogenase deficiency
3-hydroxyacyl-coenzyme A dehydrogenase deficiency
Deficiency of 3-hydroxyacyl-CoA dehydrogenase
HAD deficiency
HADH deficiency
HADHSC deficiency
L-3-alpha-hydroxyacyl-CoA dehydrogenase, short chain, deficiency
M/SCHAD deficiency
SCHAD deficiency

Additional Information & Resources

Genetic Testing Registry: Deficiency of 3-hydroxyacyl-CoA dehydrogenase
Genetic and Rare Diseases Information Center: Hyperinsulinism due to short chain 3-hydroxylacyl-CoA dehydrogenase deficiency
National Organization for Rare Disorders (NORD)
ClinicalTrials.gov
Catalog of Genes and Diseases from OMIM: 3-HYDROXYACYL-CoA DEHYDROGENASE DEFICIENCY
Scientific Articles on PubMed: PubMed

References

Bennett MJ, Russell LK, Tokunaga C, Narayan SB, Tan L, Seegmiller A, Boriack RL, Strauss AW. Reye-like syndrome resulting from novel missense mutations in mitochondrial medium- and short-chain l-3-hydroxy-acyl-CoA dehydrogenase. Mol Genet Metab. 2006 Sep-Oct;89(1-2):74-9. doi: 10.1016/j.ymgme.2006.04.004. Epub 2006 May 24.
Bennett MJ, Spotswood SD, Ross KF, Comfort S, Koonce R, Boriack RL, IJlst L, Wanders RJ. Fatal hepatic short-chain L-3-hydroxyacyl-coenzyme A dehydrogenase deficiency: clinical, biochemical, and pathological studies on three subjects with this recently identified disorder of mitochondrial beta-oxidation. Pediatr Dev Pathol. 1999 Jul-Aug;2(4):337-45. doi: 10.1007/s100249900132.
Filling C, Keller B, Hirschberg D, Marschall HU, Jornvall H, Bennett MJ, Oppermann U. Role of short-chain hydroxyacyl CoA dehydrogenases in SCHAD deficiency. Biochem Biophys Res Commun. 2008 Mar 28;368(1):6-11. doi: 10.1016/j.bbrc.2007.10.188. Epub 2007 Nov 26.
Rinaldo P, Matern D, Bennett MJ. Fatty acid oxidation disorders. Annu Rev Physiol. 2002;64:477-502. doi: 10.1146/annurev.physiol.64.082201.154705.
Treacy EP, Lambert DM, Barnes R, Boriack RL, Vockley J, O'brien LK, Jones PM, Bennett MJ. Short-chain hydroxyacyl-coenzyme A dehydrogenase deficiency presenting as unexpected infant death: A family study. J Pediatr. 2000 Aug;137(2):257-9. doi: 10.1067/mpd.2000.107467.
Yang SY, He XY, Schulz H. 3-Hydroxyacyl-CoA dehydrogenase and short chain 3-hydroxyacyl-CoA dehydrogenase in human health and disease. FEBS J. 2005 Oct;272(19):4874-83. doi: 10.1111/j.1742-4658.2005.04911.x.