Which are the causes of Biotinidase Deficiency?

Biotinidase deficiency is a rare inherited metabolic disorder that affects the body's ability to process biotin, a B-vitamin essential for various bodily functions. This condition is caused by mutations in the BTD gene, which provides instructions for producing the biotinidase enzyme. Without sufficient biotinidase activity, the body cannot effectively recycle and utilize biotin, leading to a deficiency.

Genetic Mutations: The primary cause of biotinidase deficiency is genetic mutations in the BTD gene. These mutations can be inherited in an autosomal recessive manner, meaning that an affected individual must inherit two copies of the mutated gene (one from each parent) to develop the condition. If both parents are carriers of the mutated gene, there is a 25% chance with each pregnancy that their child will have biotinidase deficiency.

Carriers of BTD Gene Mutations: While individuals with only one copy of the mutated BTD gene are typically unaffected, they are considered carriers of biotinidase deficiency. Carriers have a reduced level of biotinidase activity, but it is usually sufficient for normal biotin processing. However, if both parents are carriers, there is a risk of passing on two mutated genes to their child, resulting in biotinidase deficiency.

Early Infant Screening: Biotinidase deficiency is often detected through newborn screening programs, which test for various genetic and metabolic disorders shortly after birth. This early screening allows for early diagnosis and prompt treatment, minimizing the potential complications associated with the condition.

Signs and Symptoms: The symptoms of biotinidase deficiency can vary widely, ranging from mild to severe. Common signs include skin rashes, hair loss, developmental delays, seizures, weak muscle tone (hypotonia), breathing difficulties, and vision problems. If left untreated, the deficiency can lead to life-threatening complications.

Treatment: Biotinidase deficiency can be effectively managed with biotin supplementation. Daily oral doses of biotin are prescribed to individuals with the condition to compensate for the lack of biotinidase activity. Early diagnosis and treatment are crucial to prevent long-term complications and ensure optimal growth and development.

Conclusion: Biotinidase deficiency is primarily caused by genetic mutations in the BTD gene, leading to reduced or absent biotinidase activity. It is important to identify carriers of the mutated gene and provide appropriate genetic counseling to prevent the condition from being passed on to future generations. Early detection through newborn screening programs and timely treatment with biotin supplementation significantly improve the prognosis for individuals with biotinidase deficiency.