[P1-69] Epilepsy in Ornithine Transcarbamylase Deficiency – Two patients with unusual presentation and neuroimaging findings
Ornithine Transcarbamylase (OTC) deficiency is the most common urea cycle defect. Seizures are not uncommon in patients with OTC deficiency, especially during periods of hyperammonemia. We describe two patients with OTC deficiency with focal and refractory multifocal epilepsy. Interestingly in both patients, the seizures did not occur during metabolic decompensation. The first patient had neuroimaging finding of bilateral mesial temporal sclerosis. This differs from most other known cases of urea cycle defects, where pathological changes occur in the white matter or deep grey nuclei. Infrequently, selective temporal lobe involvement can be seen in adult onset OTC deficiency but the first patient presented in childhood. The second patient had extensive intracranial venous sinus and cortical vein thrombosis. The extensive thrombosis observed was postulated to be due to underlying chronic mastoiditis. The two cases illustrate the importance of considering varying etiologies of seizures in patients with OTC deficiency, especially when the ammonia levels are within normal ranges.