Abstracts

Rationale: Only a few cases of duplications in the chromosome 2q 24.3 of varying sizes have been reported so far. Only one case presented with Early Infantile Epileptic Encephalopathy (EIEE) but had normal imaging and responded fairly well to antiepileptic agents(1). We report severe neonatal presentation with Ohtahara Syndrome and tonic seizures and very diffuse neuroimaging abnormalities, not yet reported in literature. Methods: We present clinical, electroencephalographic and radiologic features of a unique case. Results: Boy born at 35 weeks via spontaneous vaginal delivery, who was diagnosed with 15.5 Mb gain of 2q12.3q14.3 and 20.2 Mb gain of 2q24.3q32.1 on chorionic villus sampling. This was prompted by cystic hygroma on the prenatal ultrasound. He also has unilateral undescended testes and small kidneys.He presented at 3 weeks of age with numerous daily tonic seizures with apnea and bradycardia needing mechanical ventilation. Electroencephalogram showed burst suppression pattern and captured tonic seizures with electro-decremental pattern and ictal bradycardia (Figure 1). Brain MRI revealed thickened claustra, abnormal dentate nuclei, abnormal diffuse T2 prolongation, under sulcation and cystic olfactory bulbs. (Figure 2) Conclusions: Discussion:  Voltage gated sodium channels encoded by genes SCN1A and SCN2A located on 2q play important role in neuronal excitability. 70-80% cases of Dravet Syndrome are caused by mutations in these genes, deletion being the most common type. Microduplication in the SCN2A gene was reported in one case of a boy presenting with EIEE, responsive to antiepileptic medications and with normal brain MRI. Our case showed very widespread structural brain abnormalities and drug resistance. Our patient did not manifest hypoplastic left heart disease, cleft lip or long bone anomalies described in prior cases. This case emphasizes the expanding genotypic variations in EIEE and that structural brain abnormalities may have a genetic basis.Reference:(1)    Lim, B.C., et al. (2014) A unique phenotype of 2q24.3-2q32.1 duplication: early infantile epileptic encephalopathy without mesomelic dysplasia. J Child Neurol. 29 (2):260-4 Funding: n/a