ATP1A3. The ATPases are the “Sisphyean” workhorses of cells, perpetually bound to utilize energy generated by mitochondria to pump ions across cell membranes. This is essential to the maintenance of the intra/extracellular electrochemical gradient. ATP1A3 codes for the α3 subunit of the Na+-K+ ATPase, which utilizes ATP to actively transport sodium out of the cell and potassium into the cell. In the brain, this gradient is critical for cell signaling and for maintaining electrochemical stability, enabling cell excitation and action potential propagation. Both ATP1A3 and one of its counterparts, ATP1A2, are expressed in neurons during embryonal brain development, and ATP1A3 is also thought to contribute to regulation of non-ionic neuronal transporters and receptors. However, whereas ATP1A2 is primarily expressed in glial cells postnatally and into adulthood, ATP1A3 continues to be expressed primarily in neurons, with particular enrichment in excitatory neurons. Here is a brief overview of the clinical spectrum of ATP1A3-related disorders.
The exome decade. Last week, I accidentally looked back at our past blog posts. Exactly 10 years ago, we wrote about the discovery of ATP1A3 as the cause of Alternating Hemiplegia of Childhood (AHC). Quite a lot has happened since then in epilepsy genetics, including the discovery of at least twenty additional genes, initial clinical trials, and large-scale studies such as our Epi25 initiative. However, when seeing our 2012 blog posts, my immediate thoughts were not about achievement or progress – quite contrarily, I had the strange feeling that not much had changed in the last decade. I was reminded of a science fiction short story by Ken Liu – Cosmic Spring. Continue reading
Gene panels. Epilepsy gene panels have emerged as the first line genetic test for most suspected genetic epilepsies. Gene panels for childhood epilepsies are among the most common genetic tests ordered in a pediatric setting. While the role of gene panel testing is well established, the ideal design of gene panels remains an ongoing issue. A recent publication in the Journal of Medical Genetics provides additional evidence for the role of gene panel analysis in patients with genetic epilepsies. There are three aspects of this study that are particularly noteworthy. Continue reading
Summary. The 68th Annual Meeting of the American Epilepsy Society is now over and I would like to use this opportunity to look at five epilepsy genetics posters that caught our attention. The genetics posters at AES this year were a mixture of expansion of known phenotypes and some novel genes that might be worth looking at. Continue reading
Filling in. As Dennis is current fully engaged in the Helsinki meeting, I am filling in for him to present the most relevant publications in the field published in the last two weeks. This week’s publications were about functional studies, phenotype delineations, and novel gene findings. Continue reading