Biotinidase Deficiency: Causes, Symptoms, and Treatment
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Biotinidase Deficiency?
Biotinidase deficiency is usually managed by a metabolic specialist, a doctor who treats chemical disorders of the body. A geneticist, a doctor who treats inherited conditions, often helps. Children may also see a pediatric neurologist for nerve and brain problems. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is Biotinidase deficiency?
Biotinidase deficiency is an inherited disorder in which the body cannot recycle the vitamin biotin, also called vitamin B7. An enzyme called biotinidase normally frees biotin so the body can use it. When the enzyme is missing or weak, the body runs short. Without treatment, signs usually appear in the first months of life, but they can start later in childhood.
Symptoms
The severe form, called profound biotinidase deficiency, can cause:
- Seizures and weak muscle tone (hypotonia).
- Trouble with balance and movement (ataxia).
- Development that is slow.
- Skin rashes and hair loss (alopecia).
- Vision problems such as optic atrophy, which is damage to the nerve that carries sight signals, and hearing loss.
- Breathing problems.
- A fungal infection called candidiasis (thrush).
A milder form, called partial deficiency, may cause these problems only during stress such as an illness. Some people with the partial form never have symptoms.
Causes and who gets it
Changes in the BTD gene cause the condition. The gene carries instructions for making the biotinidase enzyme. The condition is autosomal recessive. That means a child must get a changed gene copy from both parents. Parents who carry one changed copy usually stay healthy. Profound or partial biotinidase deficiency occurs in about 1 in 60,000 newborns, based on worldwide screening.
How doctors diagnose it
Most cases are found by newborn screening, a blood test done shortly after birth. It is included in screening programs worldwide and in all 50 US states. Doctors confirm it by measuring biotinidase enzyme activity in blood. If that level is abnormal, genetic testing may look for BTD mutations. If a screening result is abnormal, biotin should start right away while more testing is done.
Treatment
Treatment is lifelong oral biotin supplementation, a daily biotin dose taken by mouth. The dose depends on how severe the deficiency is, and the doctor sets it. Children treated early usually have normal development. Biotin can prevent symptoms from starting and improve ones that already showed up. It may not fully undo nerve, hearing, or vision problems that came first. Doctors also say to avoid raw egg whites. A protein in them binds biotin. Cooked eggs are fine.
When to see a doctor
Call 911 or go to the emergency room right away if a baby or child has a seizure, has trouble breathing, or is very sleepy, hard to wake, or not responding as usual. See a doctor soon for unusual floppiness, unexplained hair loss, skin rash, or slow development.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Such a doctor can follow the child's growth and development, and coordinate the specialist visits. Longer visits can also help families keep up with the lifelong treatment plan.
Common questions
Can biotinidase deficiency be cured?
It cannot be cured, but lifelong biotin treatment controls it well. Children treated early usually have normal development. Treatment prevents most symptoms from ever starting.
How is it found in babies?
Through newborn screening, a blood test soon after birth. All 50 US states screen for it. A blood test of enzyme activity confirms it.
Why must treatment last a lifetime?
The body cannot recycle biotin on its own. Daily supplements replace what is missing. Treatment must be steady and lifelong. Only your doctor should change or stop it.
Is biotinidase deficiency passed down in families?
Yes. It is autosomal recessive, meaning a child needs a changed gene from each parent. Parents who carry one changed copy usually have no symptoms themselves.
What should people with it avoid?
Raw eggs should be avoided. A protein in raw egg white, avidin, binds biotin. Thoroughly cooked eggs are not a problem.
Sources
- MedlinePlus Genetics - Biotinidase deficiency
- NCBI Bookshelf, GeneReviews - Biotinidase Deficiency
- NCBI Bookshelf, StatPearls - Biotinidase Deficiency
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
