levoleucovorin and pipecolic-acid

Folinic acid-responsive seizures and pyridoxine-dependent epilepsy are two treatable causes of neonatal epileptic encephalopathy. The former is diagnosed by characteristic peaks on cerebrospinal fluid (CSF) monoamine metabolite analysis; its genetic basis has remained elusive. The latter is due to alpha-aminoadipic semialdehyde (alpha-AASA) dehydrogenase deficiency, associated with pathogenic mutations in the ALDH7A1 (antiquitin) gene. We report two patients whose CSF showed the marker of folinic acid-responsive seizures, but who responded clinically to pyridoxine. We performed genetic and biochemical testing of samples from these patients, and seven others, to determine the relation between these two disorders.. CSF samples were analyzed for the presence of alpha-AASA and pipecolic acid. DNA sequencing of the ALDH7A1 gene was performed.. Both patients reported here had increased CSF alpha-AASA, CSF pipecolic acid, and known or likely pathogenic mutations in the ALDH7A1 gene, consistent with alpha-AASA dehydrogenase deficiency. Analysis of CSF samples from seven other anonymous individuals diagnosed with folinic acid-responsive seizures showed similar results.. These results demonstrate that folinic acid-responsive seizures are due to alpha-AASA dehydrogenase deficiency and mutations in the ALDH7A1 gene. Thus, folinic acid-responsive seizures are identical to the major form of pyridoxine-dependent epilepsy. We recommend consideration of treatment with both pyridoxine and folinic acid for patients with alpha-AASA dehydrogenase deficiency, and consideration of a lysine restricted diet. The evaluation of patients with neonatal epileptic encephalopathy, as well as those with later-onset seizures, should include a measurement of alpha-AASA in urine to identify this likely underdiagnosed and treatable disorder.

Topics: Aldehyde Dehydrogenase; Biogenic Monoamines; DNA Mutational Analysis; Humans; Infant; Leucovorin; Linear Models; Lysine; Male; Mutation; Pipecolic Acids; Pyridoxine; Seizures; Tandem Mass Spectrometry; Vitamin B Complex

Pyridoxine-dependent seizures (PDS) is an autosomal recessive disorder characterized by seizures presenting in neonates or infants up to 3 years of age which respond to pharmacological doses of pyridoxine. Alpha-aminoadipic semialdehyde dehydrogenase (antiquitin) deficiency was identified as an underlying defect in PDS characterized by accumulation of alpha-aminoadipic semialdehyde (alpha-AASA) as a specific marker and recently folinic acid-responsive seizures (FRS) were found to be allelic to PDS as the putative mutations were identified in the antiquitin gene (ALDH7A1). alpha-AASA is known to be in reversible equilibrium with its cyclic Shiff base, delta(1)-piperideine-6-carboxylate (P6C). Pipecolic acid (PA) is another biomarker often elevated but is not specific to PDS. Here, we developed the liquid chromatography-mass spectrometry (LC-MS/MS) method to determine the analytes of alpha-AASA, P6C and PA simultaneously in plasma and validated the assay using samples from confirmed cases. This approach eliminates the extra time and expense of running multiple assays and provides valuable information for the rapid diagnosis and treatment of patients with PDS and FRS which potentially could lead to a better outcome with improved quality of life. The stability study showed that alpha-AASA and P6C were unstable even at -20 degrees C. A careful sample handling with immediate freezing and testing is required for reliable result.

Topics: 2-Aminoadipic Acid; Aldehyde Dehydrogenase; Animals; Calibration; Cattle; Child; Child, Preschool; Chromatography, Liquid; Humans; Leucovorin; Mass Spectrometry; Picolinic Acids; Pipecolic Acids; Protein Stability; Seizures; Temperature; Time Factors