Chromosomal abnormalities and epilepsy

Virtual Special Editions are collections of targeted papers curated by a Guest Editor. Here Dr Rhys Thomas of Cardiff University talks about Chromosomal Abnormalities and Epilepsy.

Editorial Introduction
Amongst the myriad of causes of epilepsy, there is incontrovertible evidence for genetic factors in many epilepsies. Whilst there has been a great deal of attention given to the Mendelian monogenetic epilepsies in recent years, in contrast have we been guilty of overlooking the less subtle chromosomal abnormalities? It is particularly important that we are reminded about karyotyping (the "low resolution") test of chromosomal integrity, because of the inability of CGH array ("high resolution karyotyping") to spot certain rearrangements such as ring chromosome 20.

This collection of papers includes two excellent shades of ring chromosome 20, one reporting 25 years of observation. A British paper from 2012 discusses four children with 1p36 deletion syndrome where epileptic apnoea was a feature alongside focal motor seizures and dysmorphic features. A detailed Japanese series of children with chromosome 8 and 9 abnormalities and status epileptics in sleep may help to give an insight into the cause of this complex syndrome. Finally, there is still a lot to gain from the report of a single case-but it does ask the question about whether there is a genuine relationship of chance occurrence. Is there a link between 22q11.2 deletion syndrome and juvenile myoclonic epilepsy? Watch this space.