Biotinidase Deficiency

Newborn Screening For 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. Carbohydrates, fats, and proteins then build-up in the blood, which can be harmful. Children with BIOT who are identified through newborn screening and begin treatment immediately usually remain healthy with normal development.

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.

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.

There are two main types of biotinidase deficiency (BIOT) that differ in severity and treatment. Both forms of the condition can cause serious health concerns.

Profound Biotinidase Deficiency is the more severe form of this condition. Signs of BIOT usually start within a few months after birth. In some cases, the symptoms may not appear until childhood. It is important to screen for and treat BIOT early because once your child experiences certain medical complications such s developmental delays, eye abnormalities, hearing loss, treatment cannot reverse any damage that has occurred.

Early signs of BIOT include:

  • Seizures
  • 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

Older children may manifest:

  • limb weakness
  • paresis
  • developmental delay
  • neurosensory hearing loss
  • optic atrophy and scotomata
  • recurrent viral and fungal infections

Partial Biotinidase Deficiency is a milder form of this condition. Without treatment, affected children may experience hypotonia, skin rashes, and hair loss, but these problems may appear only during illness, infection, or other times of stress.

The following are treatments often recommended for children with biotinidase deficiency:

  1. 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.
  2. Educate the family regarding signs, symptoms, and the need for urgent care when the infant becomes ill
  3. For those identified after irreversible consequences: assist in management, particularly with low vision aids, hearing aids or cochlear implants, developmental and educational interventions

Newborn Screening For Inborn Errors of Metabolism

Your baby's newborn screening may include testing for certain biotinidase disorders. In people with biotinidase deficiency, the body is unable to use a type of vitamin called biotin due to decreased activity of biotinidase, an enzyme that releases biotin (vitamin H) from proteins. In the United States, all babies have newborn screening tests to see if they may have certain inherited conditions when they are born.

Many babies with these disorders look and seem healthy at birth. Without treatment, these conditions can lead to serious health problems and even death. With early diagnosis and treatment, most babies with these disorders can lead healthy lives. This is why newborn screening right after birth is so important. People with this condition usually need treatment for their whole life.

How is Newborn Screening Done?

Newborn screening is done during the first few days of your baby's life—usually by a health care provider in the hospital. A few drops of blood from a heel prick are placed on a special card, called a Guthrie card.

This card with your baby's information is mailed to a special state laboratory that will test the blood sample for certain health conditions, including CF. In Nevada, newborn screening involves two blood samples, first one between 24-48 hours of age and second one between 10-14 days of age.

If your baby has a positive newborn screen suggestive of a biotinidase disorder, diagnostic testing is required to separate the true positives from false positives. Other contributing factors may cause a false positive result. As well, newborn screening is not diagnostic and follow-up evaluation is required. These specialized tests are sent to a reference laboratory for testing. Using one reference laboratory for all ordered tests is highly recommended due to smaller specimen volumes and shorter turn-around time for results.

Primary care providers (PCP) should consult with a pediatric metabolic specialist for information and guidance regarding specific diagnostic tests, reference lab results, clinical concerns, and clinical follow-up.

Visit the following websites for more information:

NBS Metabolic Consultant
Nicola Longo, MD, PHD
University of Utah Genetics/Pediatrics
295 Chipeta Way Salt Lake City, UT 84108
Phone: (801) 585-2457
Fax: (801) 587-7690

Shirley Farkas RDN, LD, CDE
Nevada Early Intervention Services
1161 S. Valley View Blvd. Las Vegas, NV 89102
Phone: (702) 486-9263
Fax: (702) 486-9262

Bente Riley, RDN, LD, CLC
Brenda Mortara, RDN, LD, CLC
Nevada Early Intervention Services
2667 Enterprise Rd. Reno, NV 89512
Phone: (775) 688-1341
Fax: (775) 688-2984