Conditions Isovaleric Acidemia
Isovaleric acidemia (IVA) is an inherited condition in which the body is unable to break down certain proteins properly. It is considered an organic acid condition because it can lead to a harmful buildup of organic acids and toxins in the body. If untreated, IVA can cause brain damage and even death. However, if the condition is identified early in life and proper treatment is begun, children with IVA oten can lead healthy lives.
Organic Acid Conditions
How common is isovaleric acidemia?
Isovaleric acidemia is estimated to affect one out of every 230,000 babies born in the United States.
Also known as
- Isovaleric acid-CoA dehydrogenase deficiency
- IVD deficiency
- Isovaleryl CoA carboxylase deficiency
Your baby’s doctor may ask you if your baby is showing any of the signs of IVA (see Early Signs, below). If your baby has certain signs, your baby’s doctor may suggest starting immediate treatment.
If your baby’s newborn screening result for isovaleric acidemia (IVA) was out of the normal range, your baby’s doctor or the state screening program will contact you to arrange for your baby to have additional testing. It is important to remember that an out-of-range screening result does not necessarily mean that your child has the condition. An out-of-range result may occur because the initial blood sample was too small or the test was performed too early. However, a few babies do have the condition, so it is very important that you go to your follow-up appointment for a confirmatory test. Because the harmful effects of untreated IVA can occur within days after birth, follow-up testing must be completed as soon as possible to determine whether or not your baby has the condition.
Follow-up testing will involve checking your baby’s urine and blood samples for harmful amounts of acids and toxins. Certain acids and toxins build up in the body when a child has an organic acid condition, so studying the levels of these substances in your baby’s body can help doctors determine if your child has a condition. For example, high levels of acylcarnitine in the blood and isovalerylglycine in the urine may be signs of the IVA. Sometimes follow-up testing may also include testing a very small sample of skin.
About Isovaleric Acidemia
There are two main forms of isovaleric acidemia (IVA), which differ by the age of onset. In one form, signs appear 1 to 14 days after birth. In the other form, signs of IVA do not appear until later in infancy or childhood (called chronic/intermittent IVA). These two forms share similar signs, but the signs of chronic/intermittent IVA are less severe than IVA in babies.
Signs of IVA include:
- Poor appetite
- Sleeping longer or more often
- A “sweaty feet” smell
Many of these signs may occur when your baby eats foods that his or her body cannot break down. They can be triggered by long periods of time without eating, illnesses, and infections.
If your baby shows any of these signs, be sure to contact your baby’s doctor immediately.
Your baby will need to be on a carefully planned diet in order to avoid the proteins and amino acids (building blocks of proteins) that may trigger many of the signs mentioned in the Early Signs section. Your baby’s doctor may recommend special formulas or foods made for children with isovaleric acidemia (IVA). These formulas will likely continue through adulthood.
It is also important for your baby to eat often. Long periods of time without food, illnesses, and infections can also trigger many of the signs of IVA.
Supplements and Medication
Not all amino acids are bad for your baby. Leucine is the amino acid that cannot be broken down, but glycine is a helpful amino acid. Your baby might need glycine supplements to get rid of harmful organic acids that result from this condition. Your baby’s doctor can write a prescription for these supplements.
Your baby’s doctor might also prescribe L-carnitine supplements. L-carnitine is a natural substance, but your baby’s body might not make enough of it. These supplements can help remove harmful waste products from the body.
With early and careful treatment, your child will most likely have a healthy life with typical growth and development.
Without treatment, babies with isovaleric acidemia (IVA) can suffer brain damage or even die within the first year of life.
When we eat food, enzymes help break it down. Some enzymes help break down proteins into their building blocks, amino acids. Other enzymes break down these amino acids. In isovaleric acidemia (IVA), the enzyme isovaleryl-CoA dehydrogenase is not working correctly.
This enzyme’s job is to breaks down the amino acid leucine. Babies with IVA either do not make enough or make non-working isovaleryl-CoA dehydrogenase. If your baby has IVA, his or her body cannot break down leucine. This results in the harmful buildup of organic acids in the body.
IVA is an autosomal recessive genetic condition. This means that a child must inherit two copies of the non-working gene for IVA, one from each parent, in order to have the condition. The parents of a child with an autosomal recessive condition each carry one copy of the non-working gene, but they typically do not show signs and symptoms of the condition. While having a child with IVA is rare, when both parents are carriers, they can have more than one child with the condition. Learn more about autosomal recessive inheritance.
Support for Isovaleric Acidemia
Support groups can help connect families who have a child or other family member affected with isovaleric acidemia with a supportive community of people who have experience and expertise in living with the condition. These organizations offer resources for families, affected individuals, health care providers, and advocates.
Work with your baby’s doctor to determine the next steps for your baby’s care. Your baby’s doctor may help you coordinate care with a physician who specializes in metabolism, a dietician who can help plan your child’s specialized diet, or other medical resources in your community. Some children with isovaleric acidemia (IVA) have developmental delays. If you think that your baby is not meeting his or her developmental milestones, ask your baby’s doctor about the next steps in accessing a developmental evaluation and care.
Because IVA is a genetic condition, you may want to talk with a genetics specialist. A genetic counselor or geneticist can help you understand the causes of the condition, discuss genetic testing for IVA, and understand what this diagnosis means for other family members and future pregnancies. Speak with your baby’s doctor about getting a referral. The Clinic Services Search Engine offered by the National Coordinating Center for the Regional Genetic and Newborn Screening Service Collaboratives and the Find a Genetic Counselor tool on the National Society of Genetic Counselors (NSGC) website are two good places for you or your baby's health care provider to use to identify local specialists.
Elizabeth Brooker, an adult woman with isovaleric acidemia who just gave birth to a healthy boy, has written her success story. You can read it on the Organic Acidemia Association (OAA) website. You can read more stories at the OAA website by clicking on the family photos at the bottom of this page:
Hayden was diagnosed with isovaleric acidemia shortly after birth. Through an interview with his parents, this video shows the story of his diagnosis and treatment.
References & Sources
http://ghr.nlm.nih.gov/gene/IVDVisit the Organic Acidemia Association for more condition information http://www.oaanews.org/index.htmVisit OMIM to search its online catalog of human genes and disordershttp://www.omim.org/entry/243500Visit the Screening, Technology And Research in Genetics (STAR-G) Project for more information on IVAhttp://www.newbornscreening.info/Parents/organicaciddisorders/IVA.html