Multiple Carboxylase Deficiency

Multiple carboxylase deficiency is a recessive inherited metabolic disorder. Two main forms of multiple carboxylase deficiency are known to occur:^{21, 55}

• biotinidase deficiency
• holocarboxylase synthetase deficiency

Defects in either of these two enzymes (biotinidase and holocarboxylase synthetase) will cause biotin deficiency, which can lead to serious health problems) if untreated. This is because biotin is an essential nutrient involved in metabolic functions crucial to many body systems, including the synthesis of fatty acids, the breakdown of amino acids, and the formation of glucose from carbon-based molecules other than glucogen.⁵⁵

Biotin is also needed for DNA stability and repair, as well as regulating expression of certain genes. Lack of biotin can cause illnesses that range from thinning hair to neuromuscular disorders, skin rash, vision and hearing loss, and may increase the risk for cancer, heart disease, and diabetes.⁷