see also:

• vitamins

• biotin is a coenzyme for carboxylase enzymes, involved in the synthesis of fatty acids, isoleucine, and valine, and in gluconeogenesis

• biotin deficiency is rare as intestinal bacteria generally produce biotin in excess of the body's daily requirements

• alopecia
• conjunctivitis
• dermatitis
• neurologic symptoms
• characteristic facial rash and facial fat distribution
• angular cheilitis (cracked corners of the mouth)
• fetal abnormalities