Chromosomal microarray in unexplained severe early onset epilepsy - A single centre cohort

Background: Severe early onset epilepsy may lead to impaired cognitive and motor development, and consists of a group of specific and overlapping electro-clinical phenotypes which may be the result of an inborn error of metabolism, congenital or acquired structural brain lesion, known chromosomal or mono-genetic disorder. A significant proportion of cases however remain unexplained, representing a major diagnostic and management challenge.

Methods: In this study we describe a cohort of children with severe early onset epilepsy and examine the clinical utility of chromosomal microarray (array-comparative genomic hybridisation, CGH) in this group of epilepsies.

Results: In 51 children with unexplained severe early onset epilepsy, all of whom had chromosomal array tested, copy number variants were detected in 17.6% and pathogenic variants in 5.9% of infants.

Conclusions: Chromosomal microarray is a useful investigation in early onset refractory epilepsy and epileptic encephalopathy. Detailed review of the precise array abnormality and phenotypes associated are important for determining significance.