Biotinidase Deficiency

Below you will find more information about Biotinidase Deficiency from Medigest. If you believe that you are suffering from any of the symptoms of Biotinidase Deficiency it is important that you obtain an accurate diagnosis from a medical professional to ensure that you obtain the correct medication or treatment for your condition. There are medical conditions that carry similar symptoms associated with Biotinidase Deficiency and therefore the information provided by Medigest is offered as a guideline only and should never be used in preference to seeking professional medical advice. The information relating to Biotinidase Deficiency comes from a third party source and Medigest will not be held liable for any inaccuracies relating to the information shown.


Biotinidase Deficiency (BIOT) is the result of the lack of an enzyme called biotinidase. Without treatment, this disorder can cause seizures, developmental delay, eczema, and hearing loss.


The gene defect for biotinidase deficiency is passed down unknowingly from generation to generation. This faulty gene usually appears when two carriers have children together and pass it to their offspring. For each pregnancy of two such carriers, there is a 25% chance that the child will be born with biotinidase deficiency and a 50% chance that the child will be a carrier for the gene defect. Studies show that 1 of every 60,000 infants born will have biotinidase deficiency.

Historical Background

Partial biotinidase deficiency (10-30% of mean normal activity) is often connected with an increased risk of developing the same symptoms that affect children with profound deficiency. The appearance of symptoms, however, seems to be associated with metabolic stressors (like illness, fever, fasting), and children may not be symptomatic until such time. This propensity to metabolic deterioration during stress may be a useful determinant in the diagnosis of partial deficiency, although it also is a feature of other inborn errors of metabolism. Symptoms are also responsive to biotin administration. Sudden death is often reported in association with presumed biotinidase deficiency, possibly because of seizures or brain stem dysfunction. Therefore, biotinidase deficiency should be included in the evaluation of sudden infant death syndrome, especially when other family members have possible clinical manifestations of biotinidase deficiency. The range of clinical signs and symptoms is varied. Biotinidase deficiency should be considered at presentation of intractable seizures, acidosis, rash, unexplained hearing or visual loss, spastic paraparesis, or failure to thrive. In a recent study, 38% of patients with biotinidase deficiency suffered from seizures, often in combination with other features of the disorder. Approximately 55% of these patients underwent seizures at some time during the period of review. Seizures were most frequently generalized, tonic-clonic or clonic, although myoclonic and infantile spasms were noted in a significant percentage.

Symptoms and Signs

The signs and symptoms of biotinidase deficiency generally appear within the first few months of the infant's life, but the age of onset varies. Children with profound biotinidase deficiency (the much more severe form of the condition) often have seizures, weak muscle tone (or hypotonia), breathing problems, and delayed development. If left untreated, the disorder can result to hearing loss, eye abnormalities and loss of vision, problems with movement and balance (ataxia), skin rashes, hair loss (alopecia), and a fungal infection called candidiasis. Immediate treatment and lifelong management with biotin supplements can prevent many of these complications to arise. Metabolic acidosis can result in coma and eventual death.

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