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DOI: 10.1055/s-0033-1337718
Lysine restricted diet for pyridoxine-dependent epilepsy: First reports and future trial
Aims: To evaluate the efficacy and safety of dietary lysine restriction as an adjunct to pyridoxine therapy on biochemical parameters, seizure control, and developmental/cognitive outcomes in children with pyridoxine-dependent epilepsy (PDE) caused by antiquitin (ATQ) deficiency.
Methods: Seven children aged from 28 days to 11.9 years with confirmed ATQ deficiency were treated with a dietary lysine restriction over a period of 4 months to 4.9 years. Biochemical outcomes were evaluated using pipecolic acid and α-aminoadipic semialdehyde (AASA) levels in body fluids. Developmental/cognitive outcomes were evaluated using age-appropriate tests and parental observations.
Results: Lysine restriction was well tolerated with good compliance. No adverse events were reported. Reduction in biomarker levels (baseline values before and first values after initiation of dietary lysine restriction) ranged from 20 to 67% for plasma pipecolic acid, 13 to 72% for urinary AASA, and 45% for plasma AASA. In one patient, decrease of cerebrospinal fluid levels of PA of 87% and of AASA of 82% was demonstrated. Improvement in age-appropriate skills was reported/observed in four of five patients showing prediet delays.
Conclusion: This first observational study provides level 4 evidence that lysine restriction is well tolerated. Significant reduction of potentially neurotoxic biomarkers was measured in different body compartments, with the potential to improve developmental outcomes in children with PDE caused by ATQ deficiency. Preliminary results have recently been published.1 The potentially burdensome dietary treatment cannot yet be recommended as mainstay therapy. In 2013, a prospective, international multicenter-controlled trial will be launched to further investigate the effect of the diet and achieve a higher level of evidence.
Reference
1. van Karnebeek CD, et al. Lysine restricted diet for pyridoxine-dependent epilepsy: First evidence and future trials 2012;107(3):335 – 344