Biotin and biotinidase deficiency

Abstract

Biotin is a water-soluble vitamin that serves as an essential coenzyme for five carboxylases in mammals. Biotin-dependent carboxylases catalyze the fixation of bicarbonate in organic acids and play crucial roles in the metabolism of fatty acids, amino acids and glucose. Carboxylase activities decrease substantially in response to biotin deficiency. Biotin is also covalently attached to histones; biotinylated histones are enriched in repeat regions in the human genome and appear to play a role in transcriptional repression of genes and genome stability. Biotin deficiency may be caused by insufficient dietary uptake of biotin, drug-vitamin interactions and, perhaps, by increased biotin catabolism during pregnancy and in smokers. Biotin deficiency can also be precipitated by decreased activities of the following proteins that play critical roles in biotin homeostasis: the vitamin transporters sodium-dependent multivitamin transporter and monocarboxylate transporter 1, which mediate biotin transport in the intestine, liver and peripheral tissues, and renal reabsorption; holocarboxylase synthetase, which mediates the binding of biotin to carboxylases and histones; and biotinidase, which plays a central role in the intestinal absorption of biotin, the transport of biotin in plasma and the regulation of histone biotinylation. Symptoms of biotin deficiency include seizures, hypotonia, ataxia, dermatitis, hair loss, mental retardation, ketolactic acidosis, organic aciduria and also fetal malformations. This review focuses on the deficiencies of both biotin and biotinidase, and the medical management of such cases.

Biotin-Responsive Basal Ganglia Disease: Neuroimaging Features before and after Treatment

“…The carboxylase activities decrease substantially when there is biotin deficiency. 8 The etiology of biotin deficiency is believed to be caused by a genetic defect in the transporter system of biotin across the bloodbrain barrier. 1 In 2005, it was demonstrated that homozygous mutation in SLC19A3 is the genetic defect that causes BBGD.…”

Biotina e interferenze nei metodi immunologici; problemi e opportunità

“…La biotinidasi libera la vitamina biotina dalla sua forma legata e la rende disponibile; se l'enzima manca la vitamina è perduta [7,8]. Questo deficit impedisce alle cellule di utilizzare in modo efficiente la biotina con conseguenze di diversa gravità (acidosi chetolattica, aciduria organica, iperammoniemia, rash cutanei, ipotonia, convulsioni, ritardo nella crescita, alopecia), ma si può arrivare al coma e alla morte.…”

Deficiencia de biotinidasa y malformación de anillo vascular. Reporte de un caso

“…El diagnóstico tardío o tratamiento inadecuado en etapas tempranas de la vida puede llevar a desarrollar daños neurológicos irreversibles, tales como retraso en el desarrollo y autismo. 2 Por el contrario, un diagnóstico temprano y tratamiento adecuado con administración de 5 a 10 mg por día indicado de por vida tanto en las formas de deficiencia profunda como parcial tiene una evolución favorable. Los pacientes detectados por tamizaje neonatal deberían permanecer asintomáticos de por vida si el tratamiento con biotina es precoz y sostenido continuamente.…”