Vitamin B-6 Dependency Syndromes Workup
- Author: Anjali Parish, MD; Chief Editor: Jatinder Bhatia, MBBS more...
Laboratory Studies
- Perform hematology tests, a sepsis screen, and metabolic (profile) tests.
- Plecko et al have confirmed pipecolic acid (PA) levels are elevated in the plasma of patients with pyridoxine (vitamin B-6)–dependent seizure (PDS) both before and after treatment with pyridoxine.[14] Furthermore, alpha amino adipic semialdehyde (AASA) levels are also elevated in plasma, urine, and cerebrospinal fluid (CSF).[17] They have recommended PA and AASA levels in plasma and urine be used as markers to select for patients who need molecular analysis of the antiquitin gene.[16]
Imaging Studies
- Despite several reports about imaging studies, no typical abnormality has been found in PDS.[1, 2]
- A high prevalence of structural CNS defects has been reported, as well as varying degrees of grey and white matter atrophy, thinning of the corpus callosum, and the presence of mega cisterna magna.[1]
- Progressive cortical-white matter atrophy and ventricular dilation is also present in inadequately treated patients with PDS.[1, 2]
- Hydrocephalus of unknown origin can also occur.
- Baxter reports apparent cysts adjacent to the lateral ventricles in some neonatal-onset ultrasonographic images.
- CT scanning and MRI reveal structural abnormalities in the brain in addition to white matter abnormalities.[2]
- CT scanning and MRI do not have a well-established role in the diagnosis of PDS.[1]
Other Tests
- Following pyridoxine administration, the EEG usually takes 2-6 minutes to normalize. The pattern is typically suggestive of diffuse and focal dysfunction and may show focal discharges; however, some EEG patterns have been normal (ie, bursts or runs of high-voltage, relatively bilateral synchronous sharp and slow [1-4 Hz] wave activity [either ictally or interictally]).[1]
- EEG does not have a well-established role in the diagnosis of PDS. One report suggests that the abnormal EEG is a result of the administration of anticonvulsants to the patient prior to the diagnosis of PDS.[13]
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Baxter P. Pyridoxine-dependent and pyridoxine-responsive seizures. Dev Med Child Neurol. Jun 2001;43(6):416-20. [Medline].
Yoshikawa H, Abe T, Oda Y. Pyridoxine-dependent seizures in an older child. J Child Neurol. Oct 1999;14(10):687-90. [Medline].
Gerlach AT, Thomas S, Stawicki SP, Whitmill ML, Steinberg SM, Cook CH. Vitamin B6 deficiency: a potential cause of refractory seizures in adults. JPEN J Parenter Enteral Nutr. Mar 2011;35(2):272-5. [Medline].
Hunt AD Jr, Stokes J Jr, McCrory WW, Stroud HH. Pyridoxine dependency: report of a case of intractable convulsions in an infant controlled by pyridoxine. Pediatrics. Feb 1954;13(2):140-5. [Medline].
Burd L, Stenehjem A, Franceschini LA, Kerbeshian J. A 15-year follow-up of a boy with pyridoxine (vitamin B6)-dependent seizures with autism, breath holding, and severe mental retardation. J Child Neurol. Nov 2000;15(11):763-5. [Medline].
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Kure S, Sakata Y, Miyabayashi S, et al. Mutation and polymorphic marker analyses of 65K- and 67K-glutamate decarboxylase genes in two families with pyridoxine-dependent epilepsy. J Hum Genet. 1998;43(2):128-31. [Medline].
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Baxter P. Pyridoxine dependent epilepsy: a suggestive electroclinical pattern. Arch Dis Child Fetal Neonatal Ed. Sep 2000;83(2):F163. [Medline].
Plecko B, Paul K, Paschke E, et al. Biochemical and molecular characterization of 18 patients with pyridoxine-dependent epilepsy and mutations of the antiquitin (ALDH7A1) gene. Hum Mutat. Jan 2007;28(1):19-26. [Medline].
Kanno J, Kure S, Narisawa A, et al. Allelic and non-allelic heterogeneities in pyridoxine dependent seizures revealed by ALDH7A1 mutational analysis. Mol Genet Metab. Aug 2007;91(4):384-9. [Medline].
Stockler S, Plecko B, Gospe SM Jr, Coulter-Mackie M, Connolly M, van Karnebeek C, et al. Pyridoxine dependent epilepsy and antiquitin deficiency: clinical and molecular characteristics and recommendations for diagnosis, treatment and follow-up. Mol Genet Metab. Sep-Oct 2011;104(1-2):48-60. [Medline].
Hasumi H, Kamiyama Y, Nakasora S, Yamamoto Y, Hara M, Fujita Y. Cerebrospinal fluid and serum levels of vitamin B6 in status epilepticus children. Brain Dev. Aug 2011;33(7):580-8. [Medline].
Ohtsuka Y, Ogino T, Asano T, et al. Long-term follow-up of vitamin B(6)-responsive West syndrome. Pediatr Neurol. Sep 2000;23(3):202-6. [Medline].
Hindley D, Huyton M. Pyridoxine dependent and pyridoxine responsive seizures. Arch Dis Child. Jan 2001;84(1):91-2. [Medline].

