BIOTIN

BIOTIN
Biotin is a coenzyme in carboxylation reactions involved in fatty acid synthesis, gluconeogenesis, and amino acid catabolism.
It is found throughout the diet, particularly in egg yolks, legumes, and nuts. It is also synthesized by bacteria in the human gut.
Biotin deficiency may be acquired or may be due to inborn deficiency of either holocarboxylase synthetase or biotinidase.
Acquired biotin deficiency usually results from excess intake of egg whites. Egg whites contain avidin, which blocks absorption of biotin. Deficiency also has occurred in patients receiving total parenteral nutrition without added biotin.
The clinical features are fine desquamation on the extremities, periorificial eczema, alopecia, pallor, and atrophy of the tongue. Treatment with biotin 150 µg/day corrects symptoms within 1 week.