Abstract
Vitamin B6 dependent seizure disorders are an important and treatable cause of childhood epilepsy. The molecular and biochemical basis for some of these disorders has only recently been elucidated and it is likely that inborn errors affecting other parts of this complex metabolic pathway are yet to be described. In man vitamin B6 ingested from the diet exists as six different vitamers, pyridoxal (PL), pyridoxamine (PM), pyridoxine (PN), pyridoxal 5’-phosphate (PLP), pyridoxamine 5’- phosphate (PMP) and pyridoxine 5’-phosphate (PNP). Its breakdown product, 4-pyridoxic acid (PA), is excreted in urine. Here we describe an analytical LC-MS/MS method to measure all vitameric B6 forms in plasma and have subsequently applied this methodology to investigate children with vitamin B6 responsive seizure disorders. We show that patients with inborn errors of B6 metabolism such as pyridox(am)ine 5’-phosphate oxidase (PNPO) deficiency have characteristic B6 profiles which allow them to be differentiated from each other and control populations, even when on treatment with B6. Regardless of diagnosis, patients on treatment doses of pyridoxine hydrochloride and pyridoxal phosphate have markedly elevated levels of some vitameric forms (PLP, PL and PA). Such mega doses of B6 treatment are known to be associated with neurotoxicity. This LC-MS/MS method will be a useful tool for treatment monitoring and may help further our understanding of mechanisms of neurotoxicity in patient groups.
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References
Bender DA (1999) Non-nutritional uses of Vitamin B6. Br J Nutr 81(1):7–20
Bisp MR, Bor MV, Heinsvig EM, Kall MA, Nexø E (2002) Determination of vitamin B6 vitamers and pyridoxic acid in plasma: development and evaluation of a high-performance liquid chromatographic assay. Anal Biochem 305(1):82–89
Bor MV, Refsum H, Bisp MR, Bleie O, Schneede J, Nordrehaug JE, Ueland PM et al (2003) Plasma vitamin B6 vitamers before and after oral vitamin B6 treatment: a randomised placebo-controlled study. Clin Chem 49(1):155–161
Clayton PT (2006) B6-responsive disorders: a model of vitamin dependency. J Inherit Metab Dis 29(2–3):317–326
Deitrick CL, Katholi RE, Huddleston DJ, Hardiek K, Burrus L (2001) Clinical adaptation of a high-performance liquid chromatographic method for the assay of pyridoxal 5'-phosphate in human plasma. J Chromatogr B Biomed Sci Appl 751(2):383–387
Flanagan JM, Beutler E (2006) The genetic basis of human erythrocyte pyridoxal kinase activity variation. Haematologica 91(6):801–804
Footitt EJ, Heales SJ, Mills PB, Allen GF, Oppenheim M, Clayton PT (2011) Pyridoxal 5’-phosphate in cerebrospinal fluid; factors affecting concentration. J Inherit Metab Dis 34(2):529–538
Gachon F, Fonjallaz P, Damiola F, Gos P, Kodama T, Zakany J, Duboule D, Petit B, Tafti M, Schibler U (2004) The loss of circadian PAR bZip transcription factors results in epilepsy. Genes Dev 18:1397–1412
Giraud DW, Martin HD, Driskell JA (1995) Erythrocyte and plasma B-6 vitamer concentrations of long-term tobacco smokers, chewers, and nonusers. Am J Clin Nutr 62(1):104–109
Hammen A, Wagner B, Berkhoff M, Donati F (1998) A paradoxical rise of neonatal seizures after treatment with vitamin B6. Eur J Paediatr Neurol 2(6):319–322
Hartmann H, Fingerhut M, Jakobs C, Plecko B (2011) Status epilepticus in a neonate treated with pyridoxine because of a familial recurrence risk for antiquitin deficiency: pyridoxine toxicity? Dev Med Child Neurol 53(12):1150–1153
Levine S, Saltzman A (2004) Pyridoxine (vitamin B6) neurotoxicity: enhancement by protein-deficient diet. J Appl Toxicol 24(6):497–500
Massé PG, Mahuren JD, Tranchant C, Dosy J (2004) B-6 vitamers and 4-pyridoxic acid in the plasma, erythrocytes, and urine of postmenopausal women. Am J Clin Nutr 80(4):946–951
Merrill AH, Henderson JM (1990) Vitamin B6 metabolism by human liver. Ann N Y Acad Sci 585:110–117
Midttun O, Hustad S, Solheim E, Schneede J, Ueland PM (2005) Multianalyte quantification of vitamin B6 and B2 species in the nanomolar range in human plasma by liquid chromatography-tandem mass spectrometry. Clin Chem 51(7):1206–1216
Mills PB, Footitt EJ, Mills KA, Tuschl K, Aylett S, Varadkar S, Hemingway C (2010) Genotypic and phenotypic spectrum of pyridoxine-dependent epilepsy (ALDH7A1 deficiency). Brain 133(Pt7):2148–2159
Perry TA, Weerasuriya A, Mouton PR, Holloway HW, Greig NH (2004) Pyridoxine-induced toxicity in rats: a stereological quantification of the sensory neuropathy. Exp Neurol 190(1):133–144
Ubbink JB, Serfontein WJ, Becker PJ, de Villiers LS (1987) Effect of different levels of oral pyridoxine supplementation on plasma pyridoxal-5'-phosphate and pyridoxal levels and urinary vitamin B-6 excretion. Am J Clin Nutr 46(1):78–85
Wang HS, Kuo MF, Chou ML, Hung PC, Lin KL, Hsieh MY, Chang MY (2005) Pyridoxal phosphate is better than pyridoxine for controlling idiopathic intractable epilepsy. Arch Dis Child 90(5):512–515
Windebank AJ (1985) Neurotoxicity of pyridine analogs is related to coenzyme structure. Neurochem Pathol Fall 3(3):159–167
Wozenski JR, Leklem JE, Miller LT (1979) The metabolism of small doses of vitamin B6 in men. J Nutr 110:275–285
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Professor Peter Clayton and Dr Emma Footitt are funded by Great Ormond Street Hospital Children’s Charity
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Communicated by: Cornelis Jakobs
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Footitt, E.J., Clayton, P.T., Mills, K. et al. Measurement of plasma B6 vitamer profiles in children with inborn errors of vitamin B6 metabolism using an LC-MS/MS method. J Inherit Metab Dis 36, 139–145 (2013). https://doi.org/10.1007/s10545-012-9493-y
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DOI: https://doi.org/10.1007/s10545-012-9493-y