The genetics of Doose Syndrome or Myoclonic Astatic Epilepsy

MAE. There are many distinct childhood epilepsy syndromes that we have become critically aware of in the genomic era as they are linked to prominent genetic causes, including Dravet Syndrome (SCN1A) and Epilepsy of Infancy with Migrating Focal Seizures (KCNT1). However, there are many other epilepsy syndromes where a genetic cause has long been suspected, but has remained elusive. One of the epilepsy syndromes that has largely remained unexplored is Doose Syndrome, also referred to as Myoclonic Astatic Epilepsy (MAE) or Epilepsy with Myoclonic-Atonic Seizures. In a recent study in Epilepsia, we explored the genetic architecture of Doose Syndrome and identified monogenic causes in 14% of individuals, including SYNGAP1, NEXMIF (KIAA2022), and SLC6A1. Our study suggests that Doose Syndrome is genetically heterogeneous, possibly with a distinct genetic landscape. Continue reading

SLC6A1 – a generalized epilepsy phenotype emerging

GAT1. When we first identified SLC6A1 in 2015, we were surprised that a significant proportion of patients with disease-causing variants in this gene had a rare epilepsy phenotype referred to as Myoclonic Astatic Epilepsy (MAE). Typically, at the time of gene discovery, it is often unclear how far the phenotypic spectrum expands. In a recent publication in Epilepsia, we reviewed the phenotype of 34 patients with SCL6A1-related epilepsy. Surprisingly, in contrast to many other epilepsy genes that showed a broad and occasionally non-specific phenotypic range, the SLC6A1-related phenotype expands beyond MAE, but remains centered around generalized epilepsies with a predominance of absence seizures and atonic seizures. It is a gene that has started to write its own story. Continue reading