HealthTales.com

stories of sickness and recovery
Index of Diseases and Conditions: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Isovaleric acidemia

What is isovaleric acidemia?

Isovaleric acidemia is a rare disorder in which the body is unable to process certain proteins 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.

Normally, the body breaks down proteins from food into smaller parts called amino acids. Amino acids can be further processed to provide energy for growth and development. People with isovaleric acidemia have inadequate levels of an enzyme that helps break down a particular amino acid called leucine.

Health problems related to isovaleric acidemia range from very mild to life-threatening. In severe cases, the features of isovaleric acidemia become apparent within a few days after birth. The initial symptoms include poor feeding, vomiting, seizures, and lack of energy (lethargy). These symptoms sometimes progress to more serious medical problems, including seizures, coma, and possibly death. A characteristic sign of isovaleric acidemia is a distinctive odor of sweaty feet during acute illness. This odor is caused by the buildup of a compound called isovaleric acid in affected individuals.

In other cases, the signs and symptoms of isovaleric acidemia appear during childhood and may come and go over time. Children with this condition may fail to gain weight and grow at the expected rate (failure to thrive) and often have delayed development. In these children, episodes of more serious health problems can be triggered by prolonged periods without food (fasting), infections, or eating an increased amount of protein-rich foods.

Some people with gene mutations that cause isovaleric acidemia are asymptomatic, which means they never experience any signs and symptoms of the condition.

How common is isovaleric acidemia?

Isovaleric acidemia is estimated to affect at least 1 in 250,000 people in the United States.

What genes are related to isovaleric acidemia?

Mutations in the IVD gene cause isovaleric acidemia.

The IVD gene provides instructions for making an enzyme that plays an essential role in breaking down proteins from the diet. Specifically, this enzyme helps process the amino acid leucine, which is part of many proteins. If a mutation in the IVD gene reduces or eliminates the activity of this enzyme, the body is unable to break down leucine properly. As a result, an organic acid called isovaleric acid and related compounds build up to harmful levels in the body. This buildup damages the brain and nervous system, causing serious health problems.

How do people inherit isovaleric acidemia?

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition.

Isovaleric Acidemia on Wikipedia

'''Isovaleric acidemia''' is a rare genetic disorder in which the body is unable to process certain proteins properly. People with this disorder have inadequate levels of an enzyme that helps break down the amino acid leucine. It is closely related to the genteic metabolic disorder Maple syrup urine disease.

Symptoms

A characteristic feature of isovaleric acidemia is a distinctive odor of sweaty feet. This odor is caused by the buildup of a compound called isovaleric acid in affected individuals. In about half of cases, the signs and symptoms of this disorder become apparent within a few days after birth and include poor feeding, vomiting, seizures, and lethargy that can progress to coma. These medical problems are typically severe and can be life-threatening. In the other half of cases, the signs and symptoms of the disorder appear during childhood and may come and go over time. They are often triggered by an infection or by eating an increased amount of protein-rich foods. The urine of newborn can be screened with mass spectrometry for isovaleric acid, allowing for presymptomatic diagnosis.

Genetics

Isovaleric acidemia is estimated to affect at least 1 in 250,000 births in the United States. The condition is inherited in an autosomal recessive pattern, caused by mutations in both copies of the ''IVD'' gene. The enzyme encoded by ''IVD'', isovaleric acid-CoA dehydrogenase, plays an essential role in breaking down proteins from the diet. Specifically, the enzyme is responsible for the third step in processing leucine, an amino acid that is part of many proteins. If a mutation in the IVD gene reduces or eliminates the activity of this enzyme, the body is unable to break down leucine properly. As a result, a molecule called isovaleric acid and related compounds build up to harmful levels, damaging the brain and nervous system.

References

*Budd, M. A. et al. Isovaleric acidemia: clinical ...   [ Read More ]


Related Pages on HealthTales.com:

Propionic acidemia
Methylmalonic acidemia
Glutaric acidemia type I
Glutaric acidemia type II

Share your story:

Your name

Your location

Your story