General Condition Information
What is Biotinidase deficiency
Many different enzymes break down proteins, fats, and carbohydrates in your body. Some of these enzymes need a vitamin called biotin to work properly. Biotin’s form changes slightly when it interacts with these enzymes. A different enzyme called “biotinidase” recycles biotin back to its original form so it can be used again.
Biotinidase deficiency results when biotinidase is either missing or not made correctly. Without working biotinidase, the body cannot recycle enough biotin. Then, the enzymes that need biotin cannot work well. Adding biotin to your baby’s diet can allow these enzymes to function.
There are two types of biotinidase deficiency: severe (called profound biotinidase deficiency) and mild (called partial biotinidase deficiency). Which form your baby has depends on how well biotinidase is working in their body.
Without enough biotin, your baby has trouble making energy and getting rid of waste. Waste products from proteins, fats, and carbohydrates that are not completely broken down can be toxic at high levels. Without treatment, these toxins can cause damage that leads to the signs and symptoms of the condition.
Newborn Screening and Follow-Up
Newborn screening for biotinidase 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 the activity of the enzyme biotinidase. Babies that do not have enough biotinidase enzyme activity might have biotinidase deficiency.
If your baby’s blood spot screening result for biotinidase 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. Babies with this condition can have serious health problems in the months after birth if they are not diagnosed and treated quickly.
False-positive newborn screening results for this condition can happen. Babies born early (premature) may have out-of-range results. Screening samples that are exposed to high heat or humidity or that take a long time to get to the testing lab may have false positive results.
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. Your baby may need to get treatment right away, even if they are not showing signs or symptoms. In some cases, your baby’s health care provider may decide it is best to watch (monitor) your baby to decide next steps. Careful monitoring and early treatment will help your baby stay as healthy as possible.
Signs of biotinidase deficiency often appear within the first few months of life but may also appear later in childhood. Common illnesses, like cold or flu, or stress can trigger symptoms.
Signs of the condition may include the following:
The condition is caused by a change in the BTD gene. This gene gives your body instructions for making the enzyme biotinidase. Biotinidase recycles the biotin that other enzymes use to break down food into energy so that it can be used again.
Without a working BTD gene, your baby does not make enough working biotinidase. They cannot reuse the biotin that they have, so their bodies need more new biotin every day. If they do not get new biotin, they have trouble breaking down food into energy and waste. Toxins from waste can damage their body.
- Biotinidase deficiency is an autosomal recessive condition. Babies inherit the condition when each parent passes down a nonworking BTD gene to their baby. Only babies with two nonworking BTD genes—one from the mom and one from the dad—have this condition.
- People with one working copy and one nonworking copy of the BTD 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 BTD gene, they have a 1 in 4 chance of having a child with biotinidase deficiency.
- Carriers for biotinidase 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 biotinidase deficiency.
- Parents who already have a child with biotinidase deficiency still have a 1 in 4 chance of having another child with biotinidase 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
It is important to talk to your health care provider about which treatment(s) are best for your baby. The goal of treatment is to prevent the health problems caused by this condition.
Treatment may include biotin supplements to help the body break down food.
Children who receive early and ongoing treatment for biotinidase deficiency can have healthy growth and development.