Conditions Biotinidase Deficiency
Biotinidase deficiency (BIOT) is an inherited condition in which the body is unable to reuse and recycle the vitamin biotin. Because the body needs free biotin to break down fats, proteins, and carbohydrates effectively, individuals with BIOT are less able to process important nutrients. There are two types biotinidase deficiency (BIOT) that differ in severity and treatment. Both forms of the condition can cause serious health concerns. Children with BIOT who are identified through newborn screening and begin treatment immediately usually remain healthy with normal development.
How common is biotinidase deficiency?
Biotinidase deficiency occurs in one out of every 60,000 births. The condition is most common among individuals of European descent. However, it is reported among individuals of Turkish, Saudi Arabian, and Japanese descent, as well.
Also known as
- BTD deficiency
- Late-onset biotin-responsive multiple carboxylase deficiency
- Late-onset multiple carboxylase deficiency
Your baby’s doctor may ask you if your baby is showing any of the signs of BIOT (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 biotinidase deficiency (BIOT) was out of 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 BIOT can occur within weeks after birth, follow-up testing must be conducted as soon as possible to determine whether or not your baby has the condition.
Follow-up testing will involve a blood test to check for signs of BIOT.
About Biotinidase Deficiency
There are two main types of biotinidase deficiency (BIOT), differing in the severity of signs: severe “profound biotinidase deficiency” and mild “partial biotinidase deficiency.”
Signs of BIOT usually start within a few months after birth. In some cases, the symptoms may not appear until childhood. This is why early screening and identification is so important.
Early signs of BIOT include:
- Weak muscle tone (known as hypotonia)
- Trouble breathing
- Skin rash
- Hair loss
- Trouble balancing
- A fungal infection called candidiasis
Many of these signs can be triggered by illnesses or infections.
If your baby has any of these signs, tell your baby’s health care provider as soon as possible.
Children with biotinidase deficiency (BIOT) often require lifelong treatment with biotin supplements. This is a natural vitamin found in food, but children with BIOT might not have enough of it in their bodies. Biotin supplements can help your baby’s body break down the fats, proteins, and carbohydrates found in food. Your baby’s doctor can help determine the right dosage of biotin for your child and write an appropriate prescription. to measure the levels of certain substances in the child’s blood.
If biotinidase deficiency (BIOT) is treated, your child will likely have healthy growth and development.
It is important to screen for and treat BIOT early because once your child experiences certain medical complications such as developmental delay, eye abnormalities, or hearing loss, treatment cannot reverse any damage that has occurred.
When we eat food, enzymes help break it down. One of these enzymes, biotinidase, helps us reuse and recycle the vitamin biotin. Our bodies need biotin to help break down fats, proteins and carbohydrates.
If your baby has biotinidase deficiency (BIOT), then his or her body either does not make enough or makes non-working biotinidase enzyme. When biotinidase is not working correctly, biotin cannot be recycled and reused. If biotin cannot be recycled, then there will not be enough biotin to break down carbohydrates, fats, and proteins. Carbohydrates, fats, and proteins then build-up in the blood, which can be harmful.
BIOT is an autosomal recessive genetic condition. This means that a child must inherit two copies of the non-working gene for BIOT, 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 BIOT 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 Biotinidase Deficiency
Support groups can help connect families who have a child or other family member affected with biotinidase deficiency 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 physician may help you coordinate care with a doctor who specializes in metabolism or with other medical resources in your community.
Because biotinidase deficiency (BIOT) 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 BIOT, 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 resources for you or your baby's health care provider to use to identify local specialists.
Several years ago, many states did not screen for BIOT. William is one of the children who did not have the benefit of early detection through newborn screening. However, after a difficult first two years and with the help of a medical team, William was finally correctly diagnosed with BIOT. With the help of treatment, William has learned to walk and talk and is catching up on developmental milestones.
References & Sources
Visit the National Newborn Screening and Global Resource Center (NNSGRC) for more condition informationhttp://genes-r-us.uthscsa.edu/sites/genes-r-us/files/NBS_%20Fact%20Sheets.pdf