MG-134 Update on novel treatments for pyridoxine-dependent epilepsy due to antiquitin deficiency

Abstract

Background and objectives Seventy-five percent of patients with pyridoxine-dependent epilepsy (PDE) due to Antiquitin (ATQ) deficiency suffer developmental delay and/or intellectual disability (IQ). Methods In two open-label observational studies, seven children with confirmed ATQ deficiency were started on dietary lysine restriction with regular nutritional monitoring. Biochemical outcomes were evaluated using pipecolic acid and AASA levels in body fluids; developmental/cognitive outcomes were evaluated using age-appropriate tests and parental observations. Two other patients received additional arginine supplementation to reduce cerebral lysine flux. Results Lysine-restriction was well tolerated and diet is safe, resulted in partial normalisation of lysine intermediates in all body fluids in all patients (up to 80% reduction AASA in cerebrospinal fluid), with beneficial effects on seizure control and psychomotor development. Additional arginine fortification resulted in dramatic improvement of psychomotor development in 2 patients. Early intervention seems most effective. Discussion To disseminate these novel strategies, and generate more evidence our PDE Consortium published Recommendations, developed a Digital Diet App and established a RedCap study database (www.pdeonline.org).