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

The top three publications in epilepsy genetics 25 years ago

Looking back. In this week’s ILAE Genetics Commission post, we would like to look 25 years back and examine the most important publication in the field in 1989, the year the Berlin wall fell. What concepts did we have back then and how did our understanding of epilepsy and genes change? Here are the top three publications of 1989. Continue reading

How genome sequencing in intellectual disability breaks the 50% boundary

Exome failures. Trio exome sequencing has the huge potential to discover the genetic basis of neurodevelopmental disorders. However, the results are negative for the majority of patients. In a recent study published in Nature, genome sequencing was applied to exome-negative patients with intellectual disability, identifying mutations in coding regions that were previously missed. But are the authors correct in stating that they can explain more than 60% of cases in an unselected cohort? Continue reading

Publications of the week: genetics of Infantile Spasms, CERS1, DYRK1A, and hyaluronan

This week in epilepsy genetics. The following publications might be relevant for you, as they demonstrate what happened in the field of epilepsy genetics in the last two weeks. The publications range from basic science studies in extracellular space to novel gene discoveries. I have added a brief comment to each of these studies. Continue reading

QARS mutations, tRNA, and neurodegeneration with migrating seizures

Q for glutamine. Transfer RNAs (tRNAs) are small adaptor molecules that match a nucleotide sequence to a given amino acid during protein translation. After unloading their amino acid payload, tRNAs are recharged with new amino acids through specific tRNA synthetases. Q is the official letter for the amino acid glutamine, and its respective tRNA synthetase is glutaminyl-tRNA synthetase (QARS). In a recent publication in the American Journal of Human Genetics, Zhang and colleagues identify compound heterozygous mutations in the QARS gene in two families with progressive microcephaly, neurodegeneration, and intractable, early-onset epilepsy. Interestingly, in at least two probands, the seizures are described as migrating partial seizures reminiscent of Malignant Migrating Partial Seizures of Infancy (MMPSI) due to mutations in KCNT1. The disease mechanism, however, appears to be entirely different. Continue reading

GPHN deletions in IGE and mutation-dependent recessive inheritance

Bild1Living in Cologne is a little tough at the moment. Currently, we are in the middle of the Cologne Carnival, the world’s oldest carnival, which started in 1829. Until the upcoming Wednesday the entire city is one big festival. In addition to the 1 million Cologne citizens probably another million tourists will join. Due to this (positive) distraction I will write less than usual. However, I still consider this week’s publications noteworthy. Continue reading

Papers of the week – 15q11 duplications, Olig1 & Automated decision-making

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A productive week in epilepsy genetics.  Scientists and editors were certainly busy this week reporting novel variants and deletions as well the experimental and statistical advances for their interpretation.

A de novo GRIN2A missensmutation in early-onset epileptic encephalopathy. We and others have associated variants affecting the GRIN2A gene with a range of childhood focal epilepsy syndromes. Continue reading

Papers of the week – WES Meta analysis, Dravet mice & large sequencing studies

Bild1Time flies – already thursday night again.  Here are updates on study designs to identify rare pathogenic mutations in neurodevelopment diseases, an epilepsy animal model study as well as novel statistical frameworks for large genetic screens.

The placebo effect. In a recent paper in Science Translational Medicine the group of Kam-Hansen investigated the effect of altered placebo and drug labeling changes and its outcome in patients with episodic migraine. Their results suggest that the placebo accounted for more than 50% of the drug effect.

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A PhD in genomics – lessons learned

This is it! With finishing my PhD I have become an “adult” member of the scientific Graduierungcommunity. I grew out of a bachelor in biochemistry on transfection methods in neuronal cell lines, a research semester in Canberra with focus on B-cell immunology and master into a  PhD in epilepsy genomics. I was involved in the EPICURE IGE copy number projects and recently my work changed to the analysis of rare variants in RE and IGE in the EUROepinomics framework. During this time I was involved in the identification of variants in RBFOX genes and GRIN2A as well as other risk factors which are currently in review. I share my experience and thoughts and hope they help others who are about to or have just started their thesis. The aspects reflect my personal view and some are specific for graduation in disease genomics. Continue reading