Abstracts

Rationale: Septo-optic dysplasia (SOD) is a triad of underdevelopment of optic nerves (ON), septum pellucidum (SP)/other midline abnormalities and pituitary dysfunction. SOD can be associated w/ developmental delay, seizures (sz) and visual impairment. There are case reports of SOD patients with sz, but there are not many studies characterizing the phenotype and in this retrospective study we analyze epilepsy details, EEG findings, neuroimaging findings in SOD patients with epilepsy. Methods: After IRB approval, we identified and extracted details about patients < 21 years with midline abnormalities from the Children's databases from 2010 to 2016. Among the145 patients identified, 61 had at least 2 of the 3 abnormalities of SOD. For analysis, 2 main groups were created. Group 1: Patients with SP and ON abnormalities with/without pituitary abnormalities and 2.Patients with ON+pituitary abnormalities. Based on epilepsy, the groups were further sub grouped: A (w/ epilepsy) and B (w/out epilepsy). Patient's demographics, clinical features, sz semiology, EEG and neuroimaging findings were analyzed among the groups. Results: In 61 patients (35 males), 81% had SP and ON abnormalities with/without pituitary abnormalities. 16 % had ON and pituitary abnormalities. In the 1st group, 100% patients had absent SP and ON abnormalities in both the subgroups. Out of 25 patients in Group 1A, average sz onset age was 42 months. ~ 50% had sz onset < 12 months of age and ~16% presented with infantile spasm. 48% had seizure onset after 12 months of age with focal and generalized seizure semiology. 96% of patients had atleast one EEG. EEG findings include background slowing (44%), focal interictal epileptiform discharges (IED) (36%), multifocal IED (28%), focal slowing (36%). Seizures were controlled with single antiepileptic medication in 60 %. Developmental delay and headaches were reported in 52% of 1A compared to 24 % in1B. MRI was available in 100 % 1A compared to 96% in Group 1B. Malformations of cortical development (MCD) were seen in 72 % 1A versus 12 % in Group1B. Abnormalities in corpus callosum, ventricular size, cerebellar, hippocampus and delayed myelination were seen at 80% and 52 % in group 1A and 1B respectively. Pituitary dysfunction was seen in 60% in Group 1A and 56% in Group 1B. In Group 2, 100 % of the patients in both the subgroups had ON abnormalities, pituitary dysfunction and intact septum. Out of 5 patients in group 2A, average sz onset age was 7.2 months. 3(5) had sz onset < 12 months, with generalized sz and stayed on monotherapy. 4(5) had at least one EEG, 2(5) had background slowing, and 1(5) had focal IED. 2(5) had developmental delay. 20 % had MCD in Group 2A compared to none in Group 2B. Conclusions: In our cohort of SOD patients ~ 50% had epilepsy. A subset with absent SP presenting with seizures had complicating epilepsy requiring polytherapy and had higher incidence of MCD compared to subset with intact SP. Even in absence of sz, patients with absent SP have higher incidence of MCD compared to subset with intact SP. Future plans are to further define and characterize various subgroups of SOD patients, with a view for outcome analysis and molecular testing. Funding: N/A