Summary about Disease
Biotinidase deficiency (BTD) is an inherited metabolic disorder in which the enzyme biotinidase, responsible for recycling biotin (vitamin B7), is deficient or absent. This deficiency prevents the body from properly utilizing biotin, leading to various health problems if left untreated. BTD can be profound (complete absence of enzyme activity) or partial (reduced enzyme activity). Early diagnosis and treatment with biotin supplementation are crucial to prevent or reverse the symptoms.
Symptoms
Symptoms of biotinidase deficiency can vary in severity and may include:
Seizures
Hypotonia (low muscle tone)
Ataxia (lack of coordination)
Developmental delay
Skin rashes (eczema, seborrheic dermatitis)
Hair loss (alopecia)
Hearing loss
Optic atrophy (degeneration of the optic nerve)
Breathing problems
Acidosis (excess acid in the body)
Fungal infections (e.g., candidiasis)
Causes
Biotinidase deficiency is caused by mutations in the BTD gene. This gene provides instructions for making the biotinidase enzyme. Mutations in this gene reduce or eliminate the activity of the enzyme. BTD is inherited in an autosomal recessive pattern, meaning that both parents must carry a copy of the mutated gene for their child to be affected.
Medicine Used
The primary treatment for biotinidase deficiency is daily oral biotin supplementation. The dosage varies depending on the severity of the deficiency. Biotin is readily available and relatively inexpensive. Treatment is lifelong and generally highly effective in preventing or reversing symptoms.
Is Communicable
No, biotinidase deficiency is not communicable. It is a genetic disorder inherited from parents and cannot be spread from person to person.
Precautions
The main precaution is consistent adherence to biotin supplementation as prescribed by a healthcare professional. Regular monitoring by a doctor is necessary to ensure the appropriate dosage and to monitor for any potential complications. Genetic counseling is recommended for families with a history of BTD.
How long does an outbreak last?
Biotinidase deficiency is not an "outbreak" in the infectious disease sense. Symptoms are chronic and persistent if left untreated. With biotin supplementation, symptoms typically improve significantly or resolve completely. However, if treatment is interrupted, symptoms will likely return.
How is it diagnosed?
Biotinidase deficiency is typically diagnosed through a blood test that measures biotinidase enzyme activity. Newborn screening programs in many countries include a test for BTD. Genetic testing can also be used to confirm the diagnosis by identifying mutations in the BTD gene.
Timeline of Symptoms
Symptoms can appear from early infancy to later in childhood, and sometimes even in adulthood, depending on the severity of the deficiency (profound vs. partial). If untreated, symptoms worsen over time. With prompt diagnosis and biotin supplementation, symptoms can often be reversed, preventing further progression.
Important Considerations
Early diagnosis and treatment are crucial to prevent irreversible neurological damage and other complications.
Lifelong biotin supplementation is necessary.
Adherence to treatment is essential for maintaining health.
Regular monitoring by a physician is important.
Genetic counseling should be offered to families.
Even with treatment, some individuals may experience residual neurological or developmental issues, particularly if diagnosis and treatment were delayed.