Epilepsy in 1p36 Deletion Syndrome Is Not Associated with Deletion Size

Abstract

1p36 deletion syndrome is the most common subtelomeric deletion syndrome. The main clinical features are intellectual disability, characteristic craniofacial features, and epilepsy. Recent analysis revealed that a minimum deletion of 2.2 Mb from the telomere is essential for full manifestations of 1p36 deletion syndrome. Generally, severity of neurological symptoms in patients with 1p36 deletion syndrome correlates with the size of the deletion; however, the incidence of epilepsy does not correlate with deletion size. Some patients with minimum deletions never show symptoms of epilepsy, but there are patients who manifest intractable epilepsy, especially epileptic spasms. This evidence indicates that the responsible region for epilepsy is in the minimum deletion region, but the penetrance of epilepsy is not complete. Prognosis of brain development in patients with 1p36 deletions is related to the outcome of epilepsy treatment. Careful follow-up for infantile patients with 1p36 deletion syndrome would be recommended for early diagnosis and intervention for epilepsy.