Propionic acidemia

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Reviewed July 2007

What is propionic acidemia?

Propionic acidemia is an inherited disorder in which the body is unable to process certain parts of proteins and lipids (fats) properly. It is classified as an organic acid disorder, which is a condition that leads to an abnormal buildup of particular acids known as organic acids. Abnormal levels of organic acids in the blood (organic acidemia), urine (organic aciduria), and tissues can be toxic and can cause serious health problems.

In most cases, the features of propionic acidemia become apparent within a few days after birth. The initial symptoms include poor feeding, vomiting, loss of appetite, weak muscle tone (hypotonia), and lack of energy (lethargy). These symptoms sometimes progress to more serious medical problems, including heart abnormalities, seizures, coma, and possibly death.

Less commonly, the signs and symptoms of propionic acidemia appear during childhood and may come and go over time. Some affected children experience intellectual disability or delayed development. In children with this later-onset form of the condition, episodes of more serious health problems can be triggered by prolonged periods without food (fasting), fever, or infections.

How common is propionic acidemia?

Propionic acidemia affects about 1 in 100,000 people in the United States. The condition appears to be more common in several populations worldwide, including the Inuit population of Greenland, some Amish communities, and Saudi Arabians.

What genes are related to propionic acidemia?

Mutations in the PCCA and PCCB genes cause propionic acidemia.

The PCCA and PCCB genes provide instructions for making two parts (subunits) of an enzyme called propionyl-CoA carboxylase. This enzyme plays a role in the normal breakdown of proteins. Specifically, it helps process several amino acids, which are the building blocks of proteins. Propionyl-CoA carboxylase also helps break down certain types of fat and cholesterol in the body. Mutations in the PCCA or PCCBgene disrupt the function of the enzyme and prevent the normal breakdown of these molecules. As a result, a substance called propionyl-CoA and other potentially harmful compounds can build up to toxic levels in the body. This buildup damages the brain and nervous system, causing the serious health problems associated with propionic acidemia.

Read more about the PCCA and PCCB genes.

How do people inherit propionic acidemia?

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.

Where can I find information about diagnosis or management of propionic acidemia?

These resources address the diagnosis or management of propionic acidemia and may include treatment providers.

You might also find information on the diagnosis or management of propionic acidemia in Educational resources and Patient support.

General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.

To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.

Where can I find additional information about propionic acidemia?

You may find the following resources about propionic acidemia helpful. These materials are written for the general public.

MedlinePlus - Health information (3 links)
Genetic and Rare Diseases Information Center - Information about genetic conditions and rare diseases
Educational resources - Information pages (7 links)
Patient support - For patients and families (4 links)

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

Gene Reviews - Clinical summary (2 links)
Genetic Testing Registry - Repository of genetic test information (1 link)
ACT Sheets - Newborn screening follow up (1 link)
ClinicalTrials.gov - Linking patients to medical research
PubMed - Recent literature
OMIM - Genetic disorder catalog

What other names do people use for propionic acidemia?

hyperglycinemia with ketoacidosis and leukopenia
ketotic glycinemia
ketotic hyperglycinemia
PCC deficiency
PROP
propionicacidemia
propionyl-CoA carboxylase deficiency

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines and How are genetic conditions and genes named? in the Handbook.

What if I still have specific questions about propionic acidemia?

Ask the Genetic and Rare Diseases Information Center

Where can I find general information about genetic conditions?

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 propionic acidemia?

acids ; aciduria ; amino acid ; autosomal ; autosomal recessive ; carboxylase ; cell ; cholesterol ; CoA ;coma ; deficiency ; disability ; enzyme ; fasting ; fever ; gene ; hypotonia ; lethargy ; metabolism ;muscle tone ; nervous system ; newborn screening ; organic acid ; population ; recessive ; screening ; toxic

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

References (6 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.