Abstract
Summary15q13.3 microdeletions are the most common genetic findings identified in idiopathic generalized epilepsies to date, and they are present in up to 1% of patients. In addition, 15q13.3 microdeletions have been described in patients with epilepsy as part of a complex neurodevelopmental phenotype. We analyzed a cohort of 570 patients with various pediatric epilepsies for 15q13.3 microdeletions. Screening was performed using quantitative polymerase chain reaction; deletions were confirmed by array comparative genomic hybridization (CGH). We carried out detailed phenotyping of deletion carriers. In total, we identified four pediatric patients with 15q13.3 microdeletions, including one previously described patient. Two of four deletions were de novo, one deletion was inherited from an unaffected parent, and for one patient the inheritance is unknown. All four patients had absence epilepsy with various degrees of intellectual disability. We suggest that absence epilepsy accompanied by intellectual disability may represent a common phenotype of the 15q13.3 microdeletion in pediatric patients with epilepsy.
Highlights
Structural genomic variations are increasingly recognized as genetic risk factors for various epilepsies (Mefford et al, 2010)
In a cohort of 570 pediatric patients, we identified three individuals with a 15q13.3 microdeletion
All three individuals as well as a previously described patient presented with various degrees of intellectual disability and absence epilepsy
Summary
Structural genomic variations are increasingly recognized as genetic risk factors for various epilepsies (Mefford et al, 2010). Among the different microdeletions described to date, 15q13.3 stands out as the most common genetic risk factor for epilepsy. 15q13.3 microdeletions are found in up to 1% of patients with idiopathic generalized epilepsy (IGE) (Dibbens et al, 2009; Helbig et al, 2009), but have been described in other types of seizure disorders. Although15q13.3 microdeletions predispose to a wide spectrum of other neurodevelopmental disorders including intellectual disability, autism, and schizophrenia (Sharp et al, 2008; Stefansson et al, 2008; van Bon et al, 2009), epilepsy appears to be a frequent feature in deletion carriers. Address correspondence to Hiltrud Muhle, Department of Neuropediatrics, University Medical Center Schleswig-Holstein, Kiel Campus, Arnold-Heller-Str., Building 9, 24105 Kiel, Germany.
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