Medical Conditions

Biotinidase Deficiency in Babies

Medically reviewed by Dr. Michael Okonkwo, MD, FAAP · Board-Certified Neonatologist

Content reviewed against published NIH, HRSA, ACMG guidelines

Editorial policy

Last reviewed:

If your baby has been diagnosed with or you suspect biotinidase deficiency in babies, here is what the evidence says.

The short answer

Biotinidase deficiency is an inherited metabolic disorder in which the body cannot properly recycle the vitamin biotin, which is essential for several important enzymes. Without treatment, it causes seizures, low muscle tone (hypotonia), skin rash, hair loss, hearing loss, and developmental delay. The remarkable news is that biotinidase deficiency is one of the most treatable metabolic conditions — daily biotin supplementation completely prevents all symptoms when started early through newborn screening. Children treated from birth develop entirely normally.

Key takeaways

  • Biotinidase deficiency is an inherited metabolic disorder in which the body cannot properly recycle the vitamin biotin, which is essential for several important enzymes. Without treatment, it causes seizures, low muscle tone (hypotonia), skin rash, hair loss, hearing loss, and developmental delay. The remarkable news is that biotinidase deficiency is one of the most treatable metabolic conditions — daily biotin supplementation completely prevents all symptoms when started early through newborn screening. Children treated from birth develop entirely normally.
  • Usually normal when: Your baby's newborn screening came back normal for biotinidase deficiency
  • Call your doctor if: Your baby with known biotinidase deficiency has missed several days of biotin supplementation and develops seizures, a skin rash, or becomes lethargic — resume biotin immediately and contact your metabolic team
  • Varies by age — see the age-by-age breakdown below
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— Fever and Your Child, American Academy of Pediatrics (AAP)

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What Parents Should Know

According to NIH, HRSA, ACMG guidelines, biotinidase deficiency is an inherited metabolic disorder in which the body cannot properly recycle the vitamin biotin, which is essential for several important enzymes. Without treatment, it causes seizures, low muscle tone (hypotonia), skin rash, hair loss, hearing loss, and developmental delay. The remarkable news is that biotinidase deficiency is one of the most treatable metabolic conditions — daily biotin supplementation completely prevents all symptoms when started early through newborn screening. Children treated from birth develop entirely normally. At 0-1 month, babies with biotinidase deficiency appear completely normal at birth. Newborn screening detects the enzyme deficiency before any symptoms develop. If your baby's newborn screen is positive for biotinidase deficiency, confirmatory testing will measure the level of biotinidase enzyme activity. Profound deficiency (less than 10% enzyme activity) requires lifelong biotin supplementation. Partial deficiency (10-30% enzyme activity) may also benefit from biotin supplementation, especially during times of stress or illness. Treatment is simple — daily oral biotin, an inexpensive and widely available vitamin. It is generally considered normal when your baby's newborn screening came back normal for biotinidase deficiency. However, you should contact your pediatrician promptly if your baby with known biotinidase deficiency has missed several days of biotin supplementation and develops seizures, a skin rash, or becomes lethargic — resume biotin immediately and contact your metabolic team.

Sources: [1], [2], [3]

Normal vs. Concerning

Usually Normal
Worth Discussing
Your baby's newborn screening came back normal for biotinidase deficiency
Your baby with known biotinidase deficiency has missed several days of biotin supplementation and develops seizures, a skin rash, or becomes lethargic — resume biotin immediately and contact your metabolic team
Your baby was diagnosed with biotinidase deficiency, is taking daily biotin, and is developing completely normally
Your baby has seizures that are not responding to standard treatment, combined with a distinctive rash around the face and hair loss — ask your doctor about biotinidase testing as a possible treatable cause
Confirmatory testing showed partial biotinidase deficiency, and your baby is on biotin supplementation as a precaution and is thriving
Your child with biotinidase deficiency develops hearing changes that may indicate hearing loss — early audiology evaluation is important
An initial borderline screen was followed by confirmatory testing showing adequate enzyme activity
Your baby received an abnormal biotinidase deficiency result on newborn screening — follow up for confirmatory testing to determine if treatment is needed

When to Seek Immediate Care

  • Your baby with known biotinidase deficiency has missed several days of biotin supplementation and develops seizures, a skin rash, or becomes lethargic — resume biotin immediately and contact your metabolic team
  • Your baby has seizures that are not responding to standard treatment, combined with a distinctive rash around the face and hair loss — ask your doctor about biotinidase testing as a possible treatable cause
  • Your child with biotinidase deficiency develops hearing changes that may indicate hearing loss — early audiology evaluation is important

By Age

What to expect by age

0-1 month

Babies with biotinidase deficiency appear completely normal at birth. Newborn screening detects the enzyme deficiency before any symptoms develop. If your baby's newborn screen is positive for biotinidase deficiency, confirmatory testing will measure the level of biotinidase enzyme activity. Profound deficiency (less than 10% enzyme activity) requires lifelong biotin supplementation. Partial deficiency (10-30% enzyme activity) may also benefit from biotin supplementation, especially during times of stress or illness. Treatment is simple — daily oral biotin, an inexpensive and widely available vitamin.

1-6 months

If biotinidase deficiency is not detected on newborn screening and goes untreated, symptoms can begin appearing in the first months of life. The most common early signs are seizures that do not respond well to standard seizure medications, a skin rash (often eczema-like, around the eyes, nose, and mouth), and hair loss (alopecia). The baby may develop low muscle tone and feeding difficulties. These symptoms resolve completely when biotin supplementation is started. Babies diagnosed on newborn screening and started on biotin in the first weeks of life never develop these symptoms.

6-12 months

In untreated babies, symptoms progress and can include developmental delays, hearing loss (which may become permanent if treatment is delayed too long), vision problems (optic atrophy), recurrent infections due to immune dysfunction, and metabolic acidosis. Treated babies on daily biotin have none of these problems and develop completely normally. The daily biotin dose is typically 5-20 mg for profound deficiency. Biotin is given as an oral supplement and is well-tolerated with essentially no side effects.

1 year and beyond

Children diagnosed and treated early through newborn screening have an excellent long-term prognosis — they develop normally, attend school without limitations, and live healthy lives. The only requirement is taking daily biotin supplementation lifelong. If biotin is stopped, symptoms can recur at any age. One important note: biotin supplements can interfere with some laboratory tests (particularly thyroid tests and troponin), so parents should always inform healthcare providers that their child takes biotin before any blood tests.

Late or missed diagnosis

If biotinidase deficiency is diagnosed late (after symptoms have developed), biotin supplementation will still resolve seizures, skin rash, and hair loss. However, hearing loss and vision changes that have already occurred may be permanent. This underscores the critical importance of newborn screening — every day of untreated biotinidase deficiency increases the risk of irreversible damage. If you suspect your child may have been missed on newborn screening and they have unexplained seizures, rash, or hair loss, ask your doctor about biotinidase testing.

What to Tell Your Pediatrician

  • Describe when you first noticed biotinidase deficiency in babies and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if your baby received an abnormal biotinidase deficiency result on newborn screening — follow up for confirmatory testing to determine if treatment is needed.
  • Mention if your baby has unexplained seizures combined with a skin rash or hair loss that has not been diagnosed.
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

What Should You Do?

When to take action

Probably normal when...
  • Your baby's newborn screening came back normal for biotinidase deficiency
  • Your baby was diagnosed with biotinidase deficiency, is taking daily biotin, and is developing completely normally
  • Confirmatory testing showed partial biotinidase deficiency, and your baby is on biotin supplementation as a precaution and is thriving
  • An initial borderline screen was followed by confirmatory testing showing adequate enzyme activity
Mention at your next visit when...
  • Your baby received an abnormal biotinidase deficiency result on newborn screening — follow up for confirmatory testing to determine if treatment is needed
  • Your baby has unexplained seizures combined with a skin rash or hair loss that has not been diagnosed
  • You are wondering if your child's biotin dose needs adjustment as they grow
  • Your child with biotinidase deficiency needs blood work and you want to make sure the lab knows about biotin supplementation to avoid test interference
Act now when...
  • Your baby with known biotinidase deficiency has missed several days of biotin supplementation and develops seizures, a skin rash, or becomes lethargic — resume biotin immediately and contact your metabolic team
  • Your baby has seizures that are not responding to standard treatment, combined with a distinctive rash around the face and hair loss — ask your doctor about biotinidase testing as a possible treatable cause
  • Your child with biotinidase deficiency develops hearing changes that may indicate hearing loss — early audiology evaluation is important

What You Can Do at Home

  • Keep track of when you notice biotinidase deficiency in babies — noting the time of day, duration, and any triggers can help your pediatrician.
  • Remember that your baby's newborn screening came back normal for biotinidase deficiency — this is generally within the range of normal.
  • At 0-1 month, focus on observation rather than intervention unless your pediatrician advises otherwise.
  • Follow any care instructions from your pediatrician. Keep a written log of symptoms to bring to appointments.
  • While monitoring at home, seek immediate care if your baby with known biotinidase deficiency has missed several days of biotin supplementation and develops seizures, a skin rash, or becomes lethargic — resume biotin immediately and contact your metabolic team.

Abnormal Newborn Screening Results

An abnormal or positive newborn screening result means that further testing is needed, not that your baby definitely has a condition. Most positive screens turn out to be false positives after confirmatory testing. Newborn screening tests are intentionally sensitive to avoid missing any affected babies, so follow-up testing is essential to determine whether the result is a true positive.

Types of Seizures in Babies and What They Look Like

Seizures in babies can look very different from seizures in adults. Types include subtle seizures (eye deviation, lip smacking, bicycling movements), tonic seizures (stiffening), clonic seizures (rhythmic jerking), myoclonic seizures (quick jerks), and infantile spasms (clusters of brief body flexion). Any suspected seizure in a baby needs medical evaluation. Video-recording the episode on your phone is extremely helpful for your doctor to determine if it was truly a seizure.

Patchy Hair Loss in Baby

Patchy hair loss in babies is usually caused by friction from lying on the back (positional alopecia), a very common and harmless condition. Other causes include alopecia areata, scalp ringworm, or cradle cap. Positional hair loss fills in naturally as the baby spends more time sitting up.

Triage

Rash Decision Tree

Identify common rashes and determine when to seek care.

Milestone

Month-by-Month Development

Detailed monthly development guides from birth through 24 months.

Guide

When to Call the Doctor

General guide on when to call the pediatrician, visit urgent care, or go to the ER.

Frequently asked questions

Is biotinidase deficiency in babies normal?
Biotinidase deficiency is an inherited metabolic disorder in which the body cannot properly recycle the vitamin biotin, which is essential for several important enzymes. Without treatment, it causes seizures, low muscle tone (hypotonia), skin rash, hair loss, hearing loss, and developmental delay. The remarkable news is that biotinidase deficiency is one of the most treatable metabolic conditions — daily biotin supplementation completely prevents all symptoms when started early through newborn screening. Children treated from birth develop entirely normally.
When should I call the doctor about biotinidase deficiency in babies?
Your baby with known biotinidase deficiency has missed several days of biotin supplementation and develops seizures, a skin rash, or becomes lethargic — resume biotin immediately and contact your metabolic team Your baby has seizures that are not responding to standard treatment, combined with a distinctive rash around the face and hair loss — ask your doctor about biotinidase testing as a possible treatable cause Your child with biotinidase deficiency develops hearing changes that may indicate hearing loss — early audiology evaluation is important
When is biotinidase deficiency in babies normal?
Your baby's newborn screening came back normal for biotinidase deficiency Your baby was diagnosed with biotinidase deficiency, is taking daily biotin, and is developing completely normally Confirmatory testing showed partial biotinidase deficiency, and your baby is on biotin supplementation as a precaution and is thriving
What causes biotinidase deficiency in babies?
Biotinidase deficiency is an inherited metabolic disorder in which the body cannot properly recycle the vitamin biotin, which is essential for several important enzymes. Without treatment, it causes seizures, low muscle tone (hypotonia), skin rash, hair loss, hearing loss, and developmental delay. The remarkable news is that biotinidase deficiency is one of the most treatable metabolic conditions — daily biotin supplementation completely prevents all symptoms when started early through newborn screening. Children treated from birth develop entirely normally. Common explanations include: Your baby's newborn screening came back normal for biotinidase deficiency. Your baby was diagnosed with biotinidase deficiency, is taking daily biotin, and is developing completely normally.
What should I mention to my pediatrician about biotinidase deficiency in babies?
You should mention biotinidase deficiency in babies at your next visit if: Your baby received an abnormal biotinidase deficiency result on newborn screening — follow up for confirmatory testing to determine if treatment is needed. Your baby has unexplained seizures combined with a skin rash or hair loss that has not been diagnosed. You are wondering if your child's biotin dose needs adjustment as they grow.
Is biotinidase deficiency in babies normal at 0-1 month?
Babies with biotinidase deficiency appear completely normal at birth. Newborn screening detects the enzyme deficiency before any symptoms develop. If your baby's newborn screen is positive for biotinidase deficiency, confirmatory testing will measure the level of biotinidase enzyme activity. Profound deficiency (less than 10% enzyme activity) requires lifelong biotin supplementation. Partial deficiency (10-30% enzyme activity) may also benefit from biotin supplementation, especially during times of stress or illness. Treatment is simple — daily oral biotin, an inexpensive and widely available vitamin.
Is biotinidase deficiency in babies normal at 1-6 months?
If biotinidase deficiency is not detected on newborn screening and goes untreated, symptoms can begin appearing in the first months of life. The most common early signs are seizures that do not respond well to standard seizure medications, a skin rash (often eczema-like, around the eyes, nose, and mouth), and hair loss (alopecia). The baby may develop low muscle tone and feeding difficulties. These symptoms resolve completely when biotin supplementation is started. Babies diagnosed on newborn screening and started on biotin in the first weeks of life never develop these symptoms.
Should I go to the ER for biotinidase deficiency in babies?
Seek emergency care if your baby with known biotinidase deficiency has missed several days of biotin supplementation and develops seizures, a skin rash, or becomes lethargic — resume biotin immediately and contact your metabolic team, or if your baby has seizures that are not responding to standard treatment, combined with a distinctive rash around the face and hair loss — ask your doctor about biotinidase testing as a possible treatable cause. When in doubt, call your pediatrician's after-hours line for guidance.
Does biotinidase deficiency in babies go away on its own?
In many cases, biotinidase deficiency in babies resolves on its own, especially when your baby's newborn screening came back normal for biotinidase deficiency. By Late or missed diagnosis, if biotinidase deficiency is diagnosed late (after symptoms have developed), biotin supplementation will still resolve seizures, skin rash, and hair loss. However, hearing loss and vision changes that have already occurred may be permanent. This underscores the critical importance of newborn screening — every day of untreated biotinidase deficiency increases the risk of irreversible damage. If you suspect your child may have been missed on newborn screening and they have unexplained seizures, rash, or hair loss, ask your doctor about biotinidase testing.
NIHHRSAACMG

References

  1. [1]National Library of Medicine. Biotinidase Deficiency. MedlinePlus Genetics, 2023. NIH
  2. [2]Health Resources and Services Administration. Biotinidase Deficiency Fact Sheet. Baby's First Test, 2023. HRSA
  3. [3]American College of Medical Genetics. ACT Sheet: Decreased Biotinidase Activity. ACMG, 2023. ACMG

Doctor Visit Checklist

Bring this checklist to your next pediatrician visit to discuss Biotinidase Deficiency in Babies.

Things to mention

  • Describe when you first noticed biotinidase deficiency in babies and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if your baby received an abnormal biotinidase deficiency result on newborn screening — follow up for confirmatory testing to determine if treatment is needed.
  • Mention if your baby has unexplained seizures combined with a skin rash or hair loss that has not been diagnosed.
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

Observations to share

  • Your baby received an abnormal biotinidase deficiency result on newborn screening — follow up for confirmatory testing to determine if treatment is needed
  • Your baby has unexplained seizures combined with a skin rash or hair loss that has not been diagnosed
  • You are wondering if your child's biotin dose needs adjustment as they grow

Urgent signs to report immediately

  • Your baby with known biotinidase deficiency has missed several days of biotin supplementation and develops seizures, a skin rash, or becomes lethargic — resume biotin immediately and contact your metabolic team
  • Your baby has seizures that are not responding to standard treatment, combined with a distinctive rash around the face and hair loss — ask your doctor about biotinidase testing as a possible treatable cause
  • Your child with biotinidase deficiency develops hearing changes that may indicate hearing loss — early audiology evaluation is important

My notes

From ismybabyalright.com — free, evidence-based baby health guides

All content follows our editorial policy and is reviewed against published clinical guidelines.

2,705 evidence-based guides6 authoritative medical sources5 medical advisory board members

Related Resources

Rash TriageEar Infection TriageWell-Baby Visit PrepEmergency ContactsBaby Tracker

Bottom line

Most cases of biotinidase deficiency in babies are normal. Talk to your pediatrician if your baby with known biotinidase deficiency has missed several days of biotin supplementation and develops seizures, a skin rash, or becomes lethargic — resume biotin immediately and contact your metabolic team.

Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.

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Related Medical Concerns

Abnormal Newborn Screening Results

An abnormal or positive newborn screening result means that further testing is needed, not that your baby definitely has a condition. Most positive screens turn out to be false positives after confirmatory testing. Newborn screening tests are intentionally sensitive to avoid missing any affected babies, so follow-up testing is essential to determine whether the result is a true positive.

Types of Seizures in Babies and What They Look Like

Seizures in babies can look very different from seizures in adults. Types include subtle seizures (eye deviation, lip smacking, bicycling movements), tonic seizures (stiffening), clonic seizures (rhythmic jerking), myoclonic seizures (quick jerks), and infantile spasms (clusters of brief body flexion). Any suspected seizure in a baby needs medical evaluation. Video-recording the episode on your phone is extremely helpful for your doctor to determine if it was truly a seizure.

Patchy Hair Loss in Baby

Patchy hair loss in babies is usually caused by friction from lying on the back (positional alopecia), a very common and harmless condition. Other causes include alopecia areata, scalp ringworm, or cradle cap. Positional hair loss fills in naturally as the baby spends more time sitting up.

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Adenoid Hypertrophy and Breathing

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