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Vitamins
Published in Stanley R. Resor, Henn Kutt, The Medical Treatment of Epilepsy, 2020
Another rare metabolic defect is a biotinidase deficiency, in which additional biotin is needed in the diet. Biotin is a cofactor for the enzymatic carboxylation of pyruvate, acetyl CoA, propionyl CoA, and beta methyl crotonyl CoA. Biotin is important in carbohydrate and fat metabolism. Biotinidase deficiency presents in the neonatal period or infancy with delayed development, seizures, defective immunity, and alopecia. Infants may have elevated organic acids in their urine (7,9).
Multiple carboxylase deficiency/biotinidase deficiency
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
Biotin, as a vitamin, cannot be synthesized by humans, but in addition to dietary sources, it is synthesized by intestinal microflora. There are dietary sources of free biotin, but covalently bound biotin must ultimately be acted upon by biotinidase to make biotin available from either dietary, intestinal bacterial or recycled sources (Figures 7.1 and 7.2). Biotin is an intrinsic cofactor for each of the carboxylase enzymes, which are synthesized as inactive apoenzymes and must be linked with biotin in the holocarboxylase synthetase reaction (Chapter 5) to become active holoenzymes.
Brittle Nails
Published in Nilton Di Chiacchio, Antonella Tosti, Therapies for Nail Disorders, 2020
Biotin is a water-soluble vitamin component of the B complex that acts as a coenzyme for several human carboxylases. Biotin deficiency is exceedingly rare and may be inherited or acquired. Acquired forms may occur in cases of severe malnutrition, total parenteral nutrition without biotin supplementation, long-term anticonvulsant or antibiotic therapy, and ingestion of raw egg whites. Inherited conditions include biotinidase deficiency and multiple carboxylase deficiency.
Neuro-Ophthalmic Literature Review
Published in Neuro-Ophthalmology, 2023
David A. Bellows, Noel C.Y. Chan, John J. Chen, Hui-Chen Cheng, Peter W MacIntosh, Collin McClelland, Michael S. Vaphiades, Konrad P. Weber, Xiaojun Zhang
There has been increasing recognition of genetic diseases that can cause magnetic resonance imaging (MRI) changes that mimic central nervous system (CNS) inflammatory disorders. While most of these manifest in childhood, there are some genetic diseases that can present in adulthood and cause significant diagnostic uncertainty. In this recent review in JAMA Neurology, Aryignac et al. discuss the most common adult-onset genetic diseases that can be confused with acquired neuroinflammatory disorders including genetic leukodystrophies, retinal vasculopathy with cerebral leukoencephalopathy (RVCL), Alexander’s disease, cytotoxic T-lymphocyte-associated protein haploinsufficiency, familial haemophagocytic lymphohistiocytosis, and biotinidase deficiency. Table 1 is especially helpful in summarising the MRI findings and suggestive features. Among these diseases, RVCL and biotinidase deficiency are the most likely to present in the neuro-ophthalmology clinic because their presenting symptom can be visual loss. RVCL is an autosomal dominant inflammatory microangiopathy caused by TREX1 gene mutations, which causes a vascular retinopathy, in addition to cognitive impairment, psychiatric symptoms, seizures, and focal neurological deficits. Biotinidase deficiency is an autosomal recessive disease that causes subacute bilateral optic neuropathy with central vision loss that can be accompanied by a myelopathy with longitudinal T2 lesions in the spinal cord.
Sense and nonsense concerning biotin interference in laboratory tests
Published in Acta Clinica Belgica, 2022
Alena Moerman, Joris R. Delanghe
Biotin is a water soluble vitamin/micronutrient and a coenzyme to 5 carboxylases. It is also covalently bound to lysine residues in histones. Because of this, it plays a role in the epigenetic regulation of genes, the structure of chromatin and cell signaling. Mammals cannot produce biotin and are consequently fully dependent on intake through the nutrition. Normal daily intake in western countries ranges from 35 to 70 µg per day, which lies above the daily recommended 5 to 35 µg. Our western intake pattern results in serum concentrations ranging from 0.12 to 0.36 nmol/L [4]. Rarely, people can be deficient in biotin. This shortage occurs in biotinidase deficiency (1/60089 living births) and severely malnourished children. Treatment of such a deficiency consists of 5 to 30 mg biotin per day. Biotin-thiamin-responsive basal ganglia disease is a condition that affects the nervous system. This is also treated with high dose biotin, namely 5 to 10 mg per day. In conclusion, it is unnecessary for healthy subjects to use biotin supplements. However, marketeers have made convenient use of the property of biotin to promote protein synthesis and thereby also keratin production. Supplements are available in all seizes and weights with concentrations ranging from 50 µg in multivitamin preparations to 20 mg in preparations specifically targeting growth and quality of hair and nails. Proof of this claims is however lacking, with only very little scientific evidence of any beneficial effect [5,6].
Quantification of biotin in plasma samples by column switching liquid chromatography – tandem mass spectrometry
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2021
Allan Weimann, Peter Plomgaard, Linda M. Hilsted, Henrik E. Poulsen, Emil L. Larsen
Biotin (or Vitamin B7) is a water-soluble vitamin that acts as a coenzyme for multiple carboxylases in several metabolic processes [1,2]. A whole blood biotin concentration below 0.5 nmol/L is considered compatible with deficiency of biotin as measured by the microbiological assay [3]. Acquired biotin deficiency is observed with long-term use of total parenteral nutrition without enough biotin supplementation or prolonged consumption of raw egg whites or chronic anticonvulsant therapy, but it is not a common condition. 1:75,000 children are born with an inherited deficiency of biotinidase, and analysis for mutations in encoding BTD gene is included in screening programs of new-borns. No adverse effects have been reported for up to 300 times the daily recommended intake [4]. Biotin supplementation is widely used, mainly due to proposed beneficial effects on nail and hair growth [5]. Additionally, high dose biotin supplementation has been suggested to delay progression of multiple sclerosis [6]. A recent study questioned the effects of biotin supplementation in patients with multiple sclerosis [7], and currently a large study evaluating high dose biotin supplementation is ongoing (clinicaltrials.gov: NCT03552211).