6426 Pyridoxine-dependent epilepsy, Pyridox(am)ine 5’-phosphate oxidase deficiency, and Biotinidase deficiency: experience from a Middle Eastern tertiary centre

Objectives Vitamin-responsive neurometabolic disorders are rare with early onset in life. If left undiagnosed and untreated, they can lead to significant morbidities and mortality.¹ There is a paucity of literature on the characteristics of these disorders in the Middle East. This study aims to investigate the demographics, clinical presentation and diagnostic patterns, of pyridoxine-dependent epilepsy (PDE), pyridox(am)ine 5'-phosphate oxidase deficiency (PNPOD) and biotinidase deficiency (BD) among patients at a tertiary children's hospital in the United Arab Emirates (UAE). Methods A retrospective study examined electronic health records (EHRs) of patients aged 0–18 years with PDE, PNPOD, or BD at AlJalila Children's Hospital, UAE. Data was collected from September 2016 to September 2023 after ethical approval. SPSS v26 was used for data analysis, including chi-square tests for associations. Results A total of 29 EHRs were examined. 21 patients were diagnosed with BD, 7 with PDE, and 1 patient had PNPOD. The majority of the patients (86.2%) were from Arab ethnicity. Rate of consanguinity was 20.1%. Neuroimaging was abnormal in 17.2%, with 1 in BD group, and 4 in PDE group. The most useful test that yielded positive results was genetic testing (86.2%). 34.5% of patients were diagnosed with BD via the national newborn screening program and biotin treatment was initiated promptly. Seizures were experienced by all in the PDE and PNPOD groups but by only one patient in the BD group. Skin rash and alopecia were seen in 14.2% in the BD group. At their initial presentation, 44.8% of all patients exhibited neurodevelopmental delays. 34.5% of patients continued to experience neurodevelopmental sequelae despite intervention. Among patients with seizures, 31.6% also presented with other symptoms. The mean age at seizure onset was 27.33 days (SD = 47.25), with 5 patients presenting in the neonatal period, 3 in the infantile period, and one in early childhood. Patients were diagnosed at a mean age of 74.5 months (SD = 64.3 months), ranging from 8 months to 14 years. Conclusion Early and prompt initiation of specific vitamin treatments is crucial in improving outcomes. Given their heterogeneity and varied presentations, the diagnosis of these conditions requires maintaining a high suspicion index. Genetic testing appears to be the most useful tool. Reference Curtis R Coughlin, Sidney M Gospe. Annals of the Child Neurology Society, 2023.