Biotinidase deficiency

When diagnosed early and appropriately treated with biotin supplementation, individuals with biotinidase deficiency are often asymptomatic. When biotinidase deficiency is diagnosed by newborn screening, treatment may be started prior to symptoms ever appearing in an individual, and ongoing appropriate treatment with biotin supplementation can be expected to prevent the occurrence of any symptoms.

Once an individual with untreated biotinidase deficiency becomes symptomatic, initiation of appropriate ongoing treatment with biotin supplementation can be expected to improve or eliminate some symptoms of biotinidase deficiency. However, not all symptoms of untreated biotinidase deficiency can always be reversed even with biotin therapy, making early diagnosis and treatment of biotinidase deficiency important.

If you are concerned that you or your child may have symptoms of biotinidase deficiency, you should consult with your doctor or locate genetic services in your area. The National Society of Genetic Counselors website includes a "Find A Genetic Counselor" search tool which can help you locate a genetic counselor in the United States or Canada.

Biotinidase deficiency can be classified as profound or partial, depending upon the amount of biotinidase enzyme activity present. When an individual has less than 10% of normal biotinidase activity present, it is classified as profound biotinidase activity. Individuals with 10-30% of normal biotinidase activity are referred to as having partial biotinidase activity. Left untreated, profound biotinidase activity is a more severe condition than partial biotinidase activity.

The amount of biotinidase activity can be determined in an individual by specialized blood tests, ordered by a physician.

It is recommended that individuals with biotinidase deficiency have lifelong treatment with biotin supplementation. Individuals with treated biotinidase deficiency should have yearly vision and hearing evaluations and regular physical examination by a doctor or metabolic specialist familiar with biotinidase deficiency.

In addition to ongoing treatment with biotin supplementation, individuals with biotinidase deficiency should be monitored by their physician for symptoms of biotinidase deficiency such as vision or hearing problems, skin problems, and developmental problems, as early interventions with any potential symptoms may improve outcome.

To assist in locating genetic services in your area, the National Society of Genetic Counselors website includes a searchable "Find A Genetic Counselor" directory which may be used to locate genetic counselors throughout the United States and Canada.

The symptoms that can occur in individuals with untreated biotinidase deficiency are nonspecific and can occur in many different conditions, including many inherited metabolic diseases. These symptoms may include vomiting, low muscle tone, and seizures, as well as laboratory findings involving the amount of ammonia or lactate present in the blood or urine.

Symptoms that can occur in untreated biotinidase deficiency may also be indicative of disorders such as isolated carboxylase deficiency, nutritional biotin deficiency, holocarboxylase synthetase deficiency, zinc deficiency, and essential fatty acid deficiency.

In addition to consultation with your primary care doctor, a metabolic specialist or medical geneticist can order the appropriate laboratory testing to diagnose biotinidase deficiency. To assist in locating genetic services in your area, the National Society of Genetic Counselors website includes a searchable "Find A Genetic Counselor" directory which may be used to locate genetic counselors throughout the United States and Canada.

Many of the symptoms potentially associated with untreated biotinidase deficiency are not specific to biotinidase deficiency and may be found in many other genetic or inherited metabolic conditions. However, there are a few potential symptoms of untreated profound biotinidase deficiency that are less commonly seen with other conditions and may be a clue to diagnosis, including eczema (skin rash), alopecia (hair loss), conjunctivitis (pink eye), candidiasis (a fungal infection), and ataxia (balance, coordination, and movement problem).

If you are concerned that you or your child may have symptoms of biotinidase deficiency, you should consult with your doctor or locate genetic services in your area. The National Society of Genetic Counselors website includes a "Find A Genetic Counselor" search tool which can help you locate a genetic counselor in the United States or Canada.