Natasha E. Schoeler

Can we predict a favourable response to Ketogenic Diet Therapies for drug-resistant epilepsy?

Ketogenic Dietary Therapies (KDT) are an effective treatment option for some people with drug-resistant epilepsy. They are, however, resource-intensive and can cause adverse side effects. Predictors of response would improve the selection process and perhaps further our understanding of the mechanisms behind dietary treatments for epilepsy. We conducted a literature review to identify factors that may influence response to KDT. We found no strong evidence that there are any specific factors that affect response. Gender and intellectual status do not seem to affect response; evidence is inconsistent for all other factors. Experimental studies may point us in the right direction for future work.

Ketogenic dietary therapies for adults with epilepsy: Feasibility and classification of response

Ketogenic dietary therapies are an effective treatment for children with drug-resistant epilepsy. There is currently no high-quality evidence regarding ketogenic dietary therapies in adults, and further research has been recommended. This audit aimed to provide further evidence for the feasibility of dietary treatment for adults and to consider factors that may aid response classification in this population. We evaluated the effectiveness and tolerability of ketogenic dietary therapies in 23 adults with epilepsy attending specialist clinics. Medical notes were used to obtain seizure frequency information and other effects associated with dietary treatment. Individuals who achieved ≥50% seizure reduction at all follow-up points were classified as responders. Response rates, in terms of seizure frequency, were similar to those commonly reported in pediatric cohorts: 9/23 (39%) adults were classified as responders. These responders remained on the diet for at least one year (follow-up: 1-10 years). Other benefits reported by patients, but not quantified, included a reduction in seizure severity and increased alertness and concentration. Such factors often favor continuation of ketogenic dietary therapies despite a <50% seizure reduction. One individual experienced psychosis while following dietary treatment; most commonly reported adverse events were gastrointestinal. Adverse events did not lead to discontinuation of treatment in any cases. Our findings suggest that adults with epilepsy are able to follow ketogenic dietary therapies long-term, and such treatment can lead to seizure reduction. Other aspects besides seizure frequency may be relevant when classifying response in adults, and appropriate ways to quantify these factors should be considered for use in future studies.

Genome-wide Polygenic Burden of Rare Deleterious Variants in Sudden Unexpected Death in Epilepsy.

Sudden unexpected death in epilepsy (SUDEP) represents the most severe degree of the spectrum of epilepsy severity and is the commonest cause of epilepsy-related premature mortality. The precise pathophysiology and the genetic architecture of SUDEP remain elusive. Aiming to elucidate the genetic basis of SUDEP, we analysed rare, protein-changing variants from whole-exome sequences of 18 people who died of SUDEP, 87 living people with epilepsy and 1479 non-epilepsy disease controls. Association analysis revealed a significantly increased genome-wide polygenic burden per individual in the SUDEP cohort when compared to epilepsy (P = 5.7 × 10− 3) and non-epilepsy disease controls (P = 1.2 × 10− 3). The polygenic burden was driven both by the number of variants per individual, and over-representation of variants likely to be deleterious in the SUDEP cohort. As determined by this study, more than a thousand genes contribute to the observed polygenic burden within the framework of this study. Subsequent gene-based association analysis revealed five possible candidate genes significantly associated with SUDEP or epilepsy, but no one single gene emerges as common to the SUDEP cases. Our findings provide further evidence for a genetic susceptibility to SUDEP, and suggest an extensive polygenic contribution to SUDEP causation. Thus, an overall increased burden of deleterious variants in a highly polygenic background might be important in rendering a given individual more susceptible to SUDEP. Our findings suggest that exome sequencing in people with epilepsy might eventually contribute to generating SUDEP risk estimates, promoting stratified medicine in epilepsy, with the eventual aim of reducing an individual patients risk of SUDEP.

Favourable response to ketogenic dietary therapies: undiagnosed glucose 1 transporter deficiency syndrome is only one factor

We aimed to determine whether response to ketogenic dietary therapies (KDT) was due to undiagnosed glucose transporter type 1 deficiency syndrome (GLUT1‐DS).

Variants in KCNJ11 and BAD do not predict response to ketogenic dietary therapies for epilepsy

Highlights • Common KCNJ11 and BAD variants were not associated with KDT response.• There was no consistent effect of rare variants on KDT response.• Larger cohorts may show associations from variants with effect size <3 or MAF < 0.05.• Variants with small effect sizes are unlikely to be clinically relevant.• Variants in other genes may influence response to KDT.

An examination of biochemical parameters and their association with response to ketogenic dietary therapies

In the absence of specific metabolic disorders, accurate predictors of response to ketogenic dietary therapies (KDTs) for treating epilepsy are largely unknown. We hypothesized that specific biochemical parameters would be associated with the effectiveness of KDT in humans with epilepsy. The parameters tested were β‐hydroxybutyrate, acetoacetate, nonesterified fatty acids, free and acylcarnitine profile, glucose, and glucose‐ketone index (GKI).

Correction to: The landscape of epilepsy-related GATOR1 variants

The original version of this Article contained an error in the author list where the corresponding author Stéphanie Baulac was repeated twice. This has now been corrected in the HTML, the PDF was correct at the time of publication.

The landscape of epilepsy-related GATOR1 variants

PurposeTo define the phenotypic and mutational spectrum of epilepsies related to DEPDC5, NPRL2 and NPRL3 genes encoding the GATOR1 complex, a negative regulator of the mTORC1 pathwayMethodsWe analyzed clinical and genetic data of 73 novel probands (familial and sporadic) with epilepsy-related variants in GATOR1-encoding genes and proposed new guidelines for clinical interpretation of GATOR1 variants.ResultsThe GATOR1 seizure phenotype consisted mostly in focal seizures (e.g., hypermotor or frontal lobe seizures in 50%), with a mean age at onset of 4.4 years, often sleep-related and drug-resistant (54%), and associated with focal cortical dysplasia (20%). Infantile spasms were reported in 10% of the probands. Sudden unexpected death in epilepsy (SUDEP) occurred in 10% of the families. Novel classification framework of all 140 epilepsy-related GATOR1 variants (including the variants of this study) revealed that 68% are loss-of-function pathogenic, 14% are likely pathogenic, 15% are variants of uncertain significance and 3% are likely benign.ConclusionOur data emphasize the increasingly important role of GATOR1 genes in the pathogenesis of focal epilepsies (>180 probands to date). The GATOR1 phenotypic spectrum ranges from sporadic early-onset epilepsies with cognitive impairment comorbidities to familial focal epilepsies, and SUDEP.

Genome-wide association study: Exploring the genetic basis for responsiveness to ketogenic dietary therapies for drug-resistant epilepsy

With the exception of specific metabolic disorders, predictors of response to ketogenic dietary therapies (KDTs) are unknown. We aimed to determine whether common variation across the genome influences the response to KDT for epilepsy.

Ketogenic diet in the treatment of epilepsy in children under the age of 2 years: study protocol for a randomised controlled trial

BackgroundThe incidence of epilepsy is greatest in the first 2 years of life, an age group where there is generally a poor prognosis for both seizure control and neurodevelopmental outcome. Early control of seizures can be associated with better developmental outcome but many of the epilepsies presenting in infancy are poorly responsive to antiepileptic medication. The ketogenic diet (KD) is a high-fat, low-carbohydrate diet designed to mimic the effects of starvation on the body. Dietary fat is converted into ketones in the body and used as an energy source by the brain. The KD has been shown to be successful in controlling seizures in many observational studies, and in two randomised controlled trials (RCTs) in older children. However, little evidence is available in the very young.Methods/designAn open-label RCT where eligible children (age 3 months to 2 years with epilepsy who have failed two antiepileptic drugs (AEDs)) undergo baseline assessment, including medical and seizure history. Participants then start an observation period (7 or 14 days) with documentation of seizure frequency. Randomisation will occur on day 8 or day 15 to receive the KD or a further AED; the allocated treatment will commence on day 15, with instruction and training. A second assessment (4 weeks after start of treatment) will include a clinical review and tolerability questionnaire (modified Hague Scale of Side Effects – for those allocated to the KD group). Assessments will be repeated at 8 weeks after the start of treatment including biochemical investigations, after which, according to patient response, KD (diet group) or AED (standard AED group) will then be continued or changed. Those in the AED group who have failed to achieve seizure control at the 8-week assessment will then be offered KD outside the context of the trial. Those in the KD arm who fail to achieve seizure control will be changed to standard clinical management. All patients will be followed up for 12 months from randomisation for retention, seizure outcome, quality of life and neurodevelopmental status.DiscussionThe slow rate of recruitment is an ongoing practical issue. There is a limitation to the number of eligible patients compared to what was predicted, mainly due to the nature of this patient group. After a substantial amendment to widen inclusion criteria and reduce the baseline period to 7 days for patients with a high seizure burden, the rate of recruitment steadily increased. A number of operational concerns regarding dietetic time were also highlighted impacting on the recruitment rate. However, the combination of a low dropout rate and the opening of further centres, the trial should successfully meet the final recruitment target. All nine centres are now recruiting and we hope to open further centres within the UK.Trial registrationClinicalTrials.gov, identifier: NCT02205931. Registered on 16 December 2013.