[P1-193] Clinical features and genetic analysis in intellectual disability children with epilepsy of unknown cause
[Abstract] Objective to study the clinical features, genetic causes and prognosis of intellectual disability with epilepsy (ID-E) children. Methods Unknown causes of ID-E children (n=40) were retrospectively or prospectively identified from our hospital(2015.3-2016.8) and followed up for the epilepsy control and development of intellectual. Results 40 ID-E of unexplained included 25 male (62.5%) and 34(85.0%) severe intellectual disability patients (ID<50). The on-set age of epilepsy was 0.16 to 8 years, median age was 1.5 years. 20(50.0%) had slow EEG background, and 25(62.5%) had focal spikes. 10(25.0%) had abnormal cranial images, with brain dysplasia or atrophy. Follow-up lasted from 0.58 to 1.58 years, and 19(47.5%) patients had seizure control. 25(62.5%) had used at least 2 anti-epilepsy drugs during follow-up, and 19(47.5%) had drug refractory epilepsy. Improvement of mental or motor development among epilepsy control and un-control group were 12 (63.2%) and 2 (9.5%).There were separately 8 and 3 patients diagnosed by whole genome-wide analysis of CNVs and gene-panel whose CNVs test were negative. The positive rate of genetic test was 38.8%. Conclusions ID-E of unknown cause have clinical features as followed: males, severe intellectual disability, drug refractory epilepsy patients have high percentage; well control of epilepsy is useful for improvement of mental and motor development. Genetic analysis is significant for control and prognosis of ID-E patients and genome-wide CNVs has high positive rates which can be used as first-tier test to detect genetic etiology of ID-E of unknown cause.