Galanin mutations in Temporal Lobe Epilepsy

Transmitted. When we think about epilepsy-related neurotransmitters, we often limit ourselves to the most prominent transmitters in the Central Nervous System, namely glutamate, GABA and to some extent acetylcholine. However, besides these classical transmitters, there are more than 100 small peptides released in the mammalian brain, which are referred to neuropeptides. Here is the story of galanin, the first neuropeptide in epilepsy genetics. Continue reading

TLR3 and the genetic predisposition to herpes encephalitis

Seizures with fever. Most times when we discussed seizures in the setting of fever on our blog, we either referred to simple Febrile Seizures or genetic syndromes such as Dravet Syndrome, which characteristically present with fever-associated seizures. However, if a child or an adult presents with a first seizure in the setting of a febrile illness and shows recurrent seizures or does not get back to baseline quickly, we are usually concerned about infections of the brain. Herpes simplex virus (HSV) encephalitis is one of the more common infections, which may result in significant impairment if not treated rapidly. A recent publication in Neurology reminds us of the genetic susceptibility of HSV encephalitis and suggests that predisposing genetic alterations can be found in an appreciable number of patients. Continue reading

EFHC1 – retiring an epilepsy gene

The era of gene retirement. As of 2015, the list of epilepsy genes has shrunk by one. EFHC1, a gene initially proposed to be a monogenic cause of Juvenile Myoclonic Epilepsy, is no longer an epilepsy gene. A recent study in Epilepsia finds that EFHC1 variants initially thought to be pathogenic are found in unaffected controls of the same ancestry. Follow us on one of the most perplexing journeys that modern day neurogenetics has to offer, and the retirement of the first epilepsy gene. Continue reading

Publications of the week – CNTNAP2, DEPDC5, and autism whole-genome sequencing

Issue 4/2015. Trying to keep up with the publications of the week in the field, we have selected three manuscripts this week, which challenge some of our well-established beliefs. It’s about an autism gene losing its statistical support, a familial epilepsy gene rediscovered in focal cortical dysplasia, and the surprises of whole-genome sequencing in familial autism. Continue reading

From zero to one hundred in the genetics of Febrile Seizures

Finally. Only a few months ago, we wondered what happened to the genetics of Febrile Seizures, given that there was a paucity of publications in this field. Now, a recent publication in Nature Genetics presents the first well-powered genome-wide association study in Febrile Seizures in almost 2,000 patients, including a large subgroup of patients with Febrile Seizures after MMR vaccinations. The authors provide compelling evidence for common variants in known epilepsy genes. However, the strongest genetic risk for Febrile Seizures is in a known disease gene that nobody expected. Continue reading

The 1003 possible autism genes – a matter of constraint

Overview. There have been numerous publications on de novo mutations in autism and intellectual disability over the last three years. Many of these studies struggle to distinguish signal from noise, and the plethora of findings leaves the reader wondering which genes are bona fide autism genes and in which cases the evidence is limited. A recent paper in Nature Genetics uses a new metric to assess expected versus observed de novo mutations in more than published 1000 autism patient-parent trios – and the answers appear to be straightforward. Continue reading

Magnesium, epilepsy, and CNNM2 mutations

Electrolytes. Sodium, calcium, and magnesium – I usually tell my students that imbalances in these serum electrolytes may result in seizures, when levels fall under a critical threshold. Amongst these imbalances, hypomagnesemia, a reduction of the serum magnesium level below 0.7 mmol/L, is a very rare cause of seizures, particularly in a pediatric population. However, there are genetic conditions that result in reduced magnesium levels and lead to neurological complications. In a recent paper in PLOS Genetics, the phenotype of CNNM2 mutation carriers is investigated – and magnesium is only the beginning of the story. Continue reading