General Condition Information
- Isobutyryl CoA dehydrogenase deficiency
- Isobutyryl glycinuria
- Isobutyrylglycinuria (Isobutyryl-CoA dehydrogenase deficiency)
It is unknown how many babies are born with this rare condition each year in the United States.
What is Isobutyryl-CoA dehydrogenase deficiency
Isobutyryl-CoA dehydrogenase (IBD) deficiency is an inherited (genetic) condition that prevents the body from breaking down certain proteins. IBD is an enzyme that helps you digest a part of some proteins called valine.
Without enough of this enzyme, the body may have trouble breaking down proteins that contain valine. Typically, babies with IBD deficiency have very few, if any, signs and symptoms. In fact, most health care providers do not think that IBD deficiency needs treatment.
Newborn Screening and Follow-Up
Newborn screening for IBD deficiency is done using a small amount of blood collected from your baby’s heel. To learn more about this process, visit the Blood Spot Screening page.
During screening, a special machine measures how much of certain substances (called acylcarnitines) are in your baby’s blood. The body produces these substances when it breaks down food. Babies with high levels of these substances might have IBD deficiency.
If your baby’s blood spot screening result for IBD deficiency is out-of-range, your baby’s health care provider will contact you. Together, you will discuss next steps and follow-up plans.
An out-of-range screening result does not mean that your baby definitely has the condition. It does mean that your baby needs more follow-up testing. To learn more about screening results, visit the Blood Spot Screening Results page.
Your baby may need the following tests after an out-of-range screening result:
- Blood and/or urine tests
- Genetic testing using a blood sample
You should complete any recommended follow-up testing as soon as possible.
Newborn screening helps babies lead healthier lives. If your baby has an out-of-range result, follow up with your health care provider quickly. It is important to follow their instructions. In some cases, your baby’s health care provider may decide it is best to watch (monitor) your baby to decide next steps.
Most babies and children with IBD deficiency will have no signs or symptoms. In very rare cases, some children may have the following signs:
- Floppy legs and arms (hypotonia)
- Weak and large heart (cardiomyopathy)
- Low number of red blood cells (anemia)
- Low levels of carnitine in the blood
The condition is caused by a change in the ACAD8 gene. This gene gives your body instructions to make IBD. This enzyme helps the body breakdown a part of some proteins called valine.
Without a working copy of the ACAD8 gene, your baby’s body cannot produce enough IBD enzyme to properly break down valine.
- IBD deficiency is usually an autosomal recessive condition. Babies inherit the condition when each parent passes down a nonworking ACAD8 gene to their baby. Only babies with two nonworking ACAD8 genes—one from the mom and one from the dad—have this condition.
- People with one working copy and one nonworking copy of the ACAD8 gene are called carriers.
- Carriers do not have or develop the condition. However, they may pass down a nonworking copy of the gene to their children.
- If two parents are carriers of a nonworking copy of the ACAD8 gene, they have a 1 in 4 chance of having a child with IBD deficiency.
- Carriers for IBD deficiency often do not know they are carriers before having a child with the condition. In most cases, families have no history of the condition until the birth of a child with IBD deficiency.
- Parents who already have a child with IBD deficiency due to a change in the ACAD8 gene still have a 1 in 4 chance of having another child with IBD deficiency. This 1 in 4 chance stays the same for all future children.
- Genetic counselors and medical geneticists can help families learn about this condition and the chance of having children with it. Visit the National Society of Genetic Counselors to find a genetic counselor and the American College of Medical Genetics and Genomics to find a medical geneticist.
Treatment and Management
Babies and children with IBD deficiency typically do not need any treatment. If your baby does have signs and symptoms of IBD deficiency, it is important to talk to your health care provider about which treatment(s), if any, are best for your baby.