The Efficacy of Ketogenic Diet for Specific Genetic Mutation in Developmental and Epileptic Encephalopathy

The use of ketogenic diets in children living with drug-resistant epilepsy, glucose transporter 1 deficiency syndrome and pyruvate dehydrogenase deficiency: A scoping review

BACKGROUND

The ketogenic diet (KD) is a high fat, moderate protein and very low carbohydrate diet. It can be used as a medical treatment for drug-resistant epilepsy (DRE), glucose transporter 1 deficiency syndrome and pyruvate dehydrogenase deficiency. The aim of this scoping review was to map the KD literature, with a focus on epilepsy and associated metabolic conditions, to summarise the current evidence-base and identify any gaps.

METHODS

This review was conducted using JBI scoping review methodological guidance and the PRISMA extension for scoping reviews reporting guidance. A comprehensive literature search was conducted in September 2021 and updated in February 2024 using MEDLINE, CINAHL, AMED, EmBASE, CAB Abstracts, Scopus and Food Science Source databases.

RESULTS

The initial search yielded 2721 studies and ultimately, data were extracted from 320 studies that fulfilled inclusion criteria for the review. There were five qualitative studies, and the remainder were quantitative, including 23 randomised controlled trials (RCTs) and seven quasi-experimental studies. The USA published the highest number of KD studies followed by China, South Korea and the UK. Most studies focused on the classical KD and DRE. The studies key findings suggest that the KD is efficacious, safe and tolerable.

CONCLUSIONS

There are opportunities available to expand the scope of future KD research, particularly to conduct high-quality RCTs and further qualitative research focused on the child's needs and family support to improve the effectiveness of KDs.

Genetic Testing in Pediatric Epilepsy: Tools, Tips, and Navigating the Traps

With the advent of high-throughput sequencing and computational methods, genetic testing has become an integral part of contemporary clinical practice, particularly in epilepsy. The toolbox for genetic testing has evolved from conventional chromosomal microarray and epilepsy gene panels to state-of-the-art sequencing techniques in the modern genomic era. Beyond its potential for therapeutic benefits through precision medicine, optimizing the choice of antiseizure medications, or exploring nonpharmacological therapeutic modalities, genetic testing carries substantial diagnostic, prognostic, and personal implications. Developmental and epileptic encephalopathies, the coexistence of neurodevelopmental comorbidities, early age of epilepsy onset, unexplained drug-refractory epilepsy, and positive family history have demonstrated the highest likelihood of yielding positive genetic test results. Given the diagnostic efficacy across different testing modalities, reducing costs of next-generation sequencing tests, and genetic diversity of epilepsies, exome sequencing or genome sequencing, where feasible and available, have been recommended as the first-tier test. Comprehensive clinical phenotyping at the outset, corroborative evidence from radiology and electrophysiology-based investigations, reverse phenotyping, and periodic reanalysis are some of the valuable strategies when faced with inconclusive test results. In this narrative review, the authors aim to simplify the approach to genetic testing in epilepsy by guiding on the selection of appropriate testing tools in the indicated clinical scenarios, addressing crucial aspects during pre- and post-test counseling sessions, adeptly navigating the traps posed by uncertain or negative genetic variants, and paving the way forward to the emerging testing modalities beyond DNA sequencing.

Long-term effectiveness and tolerability of ketogenic diet therapy in patients with genetic developmental and epileptic encephalopathy onset within the first 6 months of life

OBJECTIVE

To investigate the effectiveness and tolerability of ketogenic diet therapy (KDT) in patients with developmental and epileptic encephalopathy (DEE) associated with genetic etiology which onset within the first 6 months of life, and to explore the association between response to KDT and genotype/clinical parameters.

METHODS

We retrospectively reviewed data from patients with genetic DEE who started KDT at Beijing Children's Hospital between January 1, 2016, and December 31, 2021.

RESULTS

A total of 32 patients were included, involving 14 pathogenic or likely pathogenic single genes, and 16 (50.0%) patients had sodium/potassium channel gene variants. The median age at onset of epilepsy was 1.0 (IQR: 0.1, 3.0) months. The median age at initiation of KDT was 10.0 (IQR: 5.3, 13.8) months and the median duration of maintenance was 14.0 (IQR: 7.0, 26.5) months, with a mean blood β-hydroxybutyrate of 2.49 ± 0.62 mmol/L. During the maintenance period of KDT, 26 (81.3%) patients had a ≥50% reduction of seizure frequency, of which 12 (37.5%) patients achieved seizure freedom. Better responses were observed in patients with STXBP1 variants, with four out of five patients achieving seizure freedom. There were no statistically differences in the age of onset, duration of epilepsy before KDT, blood ketone values, or the presence of ion channel gene variants between the seizure-free patients and the others. The most common adverse effects were gastrointestinal side effects, which occurred in 21 patients (65.6%), but all were mild and easily corrected. Only one patient discontinued KDT due to nephrolithiasis.

SIGNIFICANCE

KDT is effective in treating early onset genetic DEE, and no statistically significant relationship has been found between genotype and effectiveness in this study. KDT is well tolerated in most young patients, with mild and reversible gastrointestinal side effects being the most common, but usually not the reason to discontinue KDT.

PLAIN LANGUAGE SUMMARY

This study evaluated the response and side effects of ketogenic diet therapy (KDT) in patients who had seizures within the first 6 months of life, and were diagnosed with genetic developmental and epileptic encephalopathy (DEE), a type of severe epilepsy with developmental delay caused by gene variants. Thirty-two patients involving 14 gene variants who started KDT at Beijing Children's Hospital between were included. KDT was effective in treating early onset genetic DEE in this cohort, and patients with STXBP1 variants responded better; however, no statistically significant relationship was found between gene variant and response. Most young patients tolerated KDT well, with mild and reversible gastrointestinal side effects being the most common.

Use of ketogenic dietary therapy for drug-resistant epilepsy in early infancy

OBJECTIVE

There is growing evidence that ketogenic dietary therapy (KDT) can be safely and efficiently used in young children, but little evidence exists on its use in newborns. Developmental and epileptic encephalopathies starting in the neonatal period or early infancy usually present a poor prognosis. The aim of this study was to evaluate effectiveness, safety, and survival of infants younger than 3 months of age with drug-resistant epilepsy in whom KDT was used.

METHODS

A retrospective study was conducted to evaluate neonates and infants younger than 3 months who started KDT for drug-resistant developmental and epileptic encephalopathies at three referral centers. Data were collected on demographic features, time of epilepsy onset, epilepsy syndrome, seizure type, seizure frequency at diet onset, etiology, details regarding diet initiation, type of ketogenic formula, breastfeeding, route of administration, blood ketones, growth, length of NICU stay, and survival.

RESULTS

Nineteen infants younger than 12 weeks of life who received KDT with a minimum follow-up of 1 month were included; 13 had early-infantile developmental and epileptic encephalopathy, four epilepsy of infancy with migrating focal seizures, and two focal epilepsy. A >50% response was observed in 73.7% at 1 month on the diet; 37% achieved a > 75% seizure reduction, and 10.5% became seizure free. At 3 months, a >50% decrease in seizure frequency was observed in 72.2%; 15.8% had a >75% reduction; 21% became seizure free. Overall survival was 76% at 1 year on diet. Incidence of acute and late adverse effects was low and most adverse effects were asymptomatic and manageable.

SIGNIFICANCE

Our experience suggests that KDT is safe and effective in newborns and very young infants; however, further studies on the management of the diet in this vulnerable age group are necessary.

Cross-population applications of genomics to understand the risk of multifactorial traits involving inflammation and immunity

The interplay between genetic and environmental factors plays a significant role in interindividual variation in immune and inflammatory responses. The availability of high-throughput low-cost genotyping and next-generation sequencing has revolutionized our ability to identify human genetic variation and understand how this varies within and between populations, and the relationship with disease. In this review, we explore the potential of genomics for patient benefit, specifically in the diagnosis, prognosis and treatment of inflammatory and immune-related diseases. We summarize the knowledge arising from genetic and functional genomic approaches, and the opportunity for personalized medicine. The review covers applications in infectious diseases, rare immunodeficiencies and autoimmune diseases, illustrating advances in diagnosis and understanding risk including use of polygenic risk scores. We further explore the application for patient stratification and drug target prioritization. The review highlights a key challenge to the field arising from the lack of sufficient representation of genetically diverse populations in genomic studies. This currently limits the clinical utility of genetic-based diagnostic and risk-based applications in non-Caucasian populations. We highlight current genome projects, initiatives and biobanks from diverse populations and how this is being used to improve healthcare globally by improving our understanding of genetic susceptibility to diseases and regional pathogens such as malaria and tuberculosis. Future directions and opportunities for personalized medicine and wider application of genomics in health care are described, for the benefit of individual patients and populations worldwide.

STXBP1-Related Disorders: Clinical Presentation, Molecular Function, Treatment, and Future Directions

In recent years, the affordability and availability of genetic testing have led to its increased use in clinical care. The increased frequency of testing has led to STXBP1 variants being identified as one of the more common variants associated with neurological disorders. In this review, we aim to summarize the common clinical phenotypes associated with STXBP1 pathogenic variants, provide an overview of their known natural history, and discuss current research into the genotype to phenotype correlation. We will also provide an overview of the suspected normal function of the STXBP1-encoded Munc18-1 protein, animal models, and experimental techniques that have been developed to study its function and use this information to try to explain the diverse phenotypes associated with STXBP1-related disorders. Finally, we will explore current therapies for STXBP1 disorders, including an overview of treatment goals for STXBP1-related disorders, a discussion of the current evidence for therapies, and future directions of personalized medications for STXBP1-related disorders.

Epileptic spasms in CDKL5 deficiency disorder: Delayed treatment and poor response to first-line therapies

OBJECTIVE

We aimed to assess the treatment response of infantile-onset epileptic spasms (ES) in CDKL5 deficiency disorder (CDD) vs other etiologies.

METHODS

We evaluated patients with ES from the CDKL5 Centers of Excellence and the National Infantile Spasms Consortium (NISC), with onset from 2 months to 2 years, treated with adrenocorticotropic hormone (ACTH), oral corticosteroids, vigabatrin, and/or the ketogenic diet. We excluded children with tuberous sclerosis complex, trisomy 21, or unknown etiology with normal development because of known differential treatment responses. We compared the two cohorts for time to treatment and ES remission at 14 days and 3 months.

RESULTS

We evaluated 59 individuals with CDD (79% female, median ES onset 6 months) and 232 individuals from the NISC database (46% female, median onset 7 months). In the CDD cohort, seizures prior to ES were common (88%), and hypsarrhythmia and its variants were present at ES onset in 34%. Initial treatment with ACTH, oral corticosteroids, or vigabatrin started within 1 month of ES onset in 27 of 59 (46%) of the CDD cohort and 182 of 232 (78%) of the NISC cohort (p < .0001). Fourteen-day clinical remission of ES was lower for the CDD group (26%, 7/27) than for the NISC cohort (58%, 106/182, p = .0002). Sustained ES remission at 3 months occurred in 1 of 27 (4%) of CDD patients vs 96 of 182 (53%) of the NISC cohort (p < .0001). Comparable results were observed with longer lead time (≥1 month) or prior treatment. Ketogenic diet, used within 3 months of ES onset, resulted in ES remission at 1 month, sustained at 3 months, in at least 2 of 13 (15%) individuals with CDD.

SIGNIFICANCE

Compared to the broad group of infants with ES, children with ES in the setting of CDD often experience longer lead time to treatment and respond poorly to standard treatments. Development of alternative treatments for ES in CDD is needed.

Clinical characteristics of 80 subjects with KCNQ2-related encephalopathy: Results from a family-driven survey

Variants of KCNQ2 are associated with a wide spectrum of disorders, ranging from Self-limiting Neonatal Epilepsy (SelNE) to Early Onset Developmental and Epileptic Encephalopathy (KCNQ2-DEE). Comorbidities associated with this end of the spectrum have been seldomly described and their impact on the life of patients and their families is yet to be investigated. Collaborating with caregivers from different European family associations, we have developed a questionnaire aimed at investigating the onset and frequency of epileptic seizures, anti-seizure medications (ASM), hospitalizations, stages of development, and comorbidities. Responses from 80 patients, 40 males, from 14 countries have been collected. Median age 7.6 years (4 months - 43.6 years). Of 76 epileptic patients (93.6%), 55.3% were seizure-free with a mean age at last seizure of 26.7 months. Among patients with active epilepsy, those older have a lower frequency of seizures (p > 0.05). We were able to identify three different clusters of varying severity (Mild, Severe, Profound), based on neurodevelopmental features and symptoms, excluding epilepsy. Patients in a higher severity cluster had a higher mean number of comorbidities, which had a higher impact on families. Notably, patients in different clusters presented different epilepsy onset and courses. This study constitutes the most extensive data collection of patients with KCNQ2-DEE, with a focus on comorbidities in a wide age group. The participation of caregivers helps to define the impact of the disease on the lives of patients and families and can help identify new primary and secondary outcomes beyond seizures in future studies.

Expansion of the clinical and molecular spectrum of WWOX-related epileptic encephalopathy

WWOX biallelic loss-of-function pathogenic single nucleotide variants (SNVs) and copy number variants (CNVs) including exonic deletions and duplications cause WWOX-related epileptic encephalopathy (WOREE) syndrome. This disorder is characterized by refractory epilepsy, axial hypotonia, peripheral hypertonia, progressive microcephaly, and premature death. Here we report five patients with WWOX biallelic predicted null variants identified by exome sequencing (ES), genome sequencing (GS), and/or chromosomal microarray analysis (CMA). SNVs and intragenic deletions of one or more exons were commonly reported in WOREE syndrome patients which made the genetic diagnosis challenging and required a combination of different diagnostic technologies. These patients presented with severe, developmental and epileptic encephalopathy (DEE), and other cardinal features consistent with WOREE syndrome. This report expands the clinical phenotype associated with this condition, including failure to thrive in most patients and epilepsy that responded to a ketogenic diet in three patients. Dysmorphic features and abnormal prenatal findings were not commonly observed. Additionally, recurrent pancreatitis and sensorineural hearing loss each were observed in single patients. In summary, these phenotypic features broaden the clinical spectrum of WOREE syndrome.

Impressive efficacy of the ketogenic diet in a KCNQ2 encephalopathy infant: a case report and exhaustive literature review

BACKGROUND

KCNQ2 encephalopathy is characterized by neonatal-onset epilepsy and developmental impairment, due to "de novo" KCNQ2 pathogenic variants. According to literature data, sodium channel blocking agents appear to be the best treatment options for the disease. Reports describing the use of ketogenic diet (KD) in the KCNQ2 pediatric population are limited. The non-conservative amino acid substitution p.Ser122Leu in KCNQ2 is associated with a broad spectrum of inheritance modalities, clinical phenotypes and outcomes; no previous reports of the same variant treated with KD are available in literature.

CASE DESCRIPTION

We described a 22-month-old female with seizure onset on day 2 of life. At three months of age, she presented refractory status epilepticus (SE) that did not respond to midazolam and carbamazepine, which was added once a "de novo" p.Ser122Leu KCNQ2 variant was demonstrated. KD was the only treatment that led to cessation of seizures. The baby maintained seizures remission and achieved neurodevelopmental milestones.

CONCLUSIONS

To define an overt genotype-phenotype correlation for KCNQ2 pathogenic variants is a challenge; we propose the KD as a valuable treatment for refractory seizures and impaired neurodevelopment in infants harboring "de novo" mutations in the KCNQ2 gene.

Ketogenic Diet for Neonatal Hypoxic-Ischemic Encephalopathy

The prevalence of neonatal hypoxic-ischemic encephalopathy (HIE), a devastating neurological injury, is increasing; thus, effective treatments and preventions are urgently needed. The underlying pathology of HIE remains unclear; recent research has focused on elucidating key features of the disease. A variety of diseases can be alleviated by consuming a ketogenic diet (KD) despite differences in pathogenesis and features, given the common mechanisms of KD-induced effects. Dietary modification is the most translatable, cost-efficient, and safest approach to treat acute or chronic neurological disorders and reduces reliance on pharmaceutical treatments. Evidence suggests that the KD can exert beneficial effects in animal models and in humans with brain injuries. The efficacy of the KD in preventing neuronal damage, motor alterations, and cognitive decline varies. Moreover, the KD may provide an alternative source of energy, enhance mitochondrial function, and reduce the expression of inflammatory and apoptotic mediators. Thus, this diet has attracted interest as a potential therapy for HIE. This review examined the role of the KD in HIE treatment and described the mechanisms by which ketone bodies (KBs) exert effects under pathological conditions and protect against brain damage; the evidence supports the implementation of dietary interventions as a therapeutic strategy for HIE. Future research should aim to elucidate the underlying mechanisms of the KD in patients with HIE and determine whether the effect of the KD on clinical outcomes can be reproduced in humans.

Efficacy of ketogenic diet in CDKL5-related epilepsy: a single arm meta-analysis

Background

Drug-resistant epilepsy is one of the most important features of cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder. The ketogenic diet (KD) may be effective for patients with CDKL5-related epilepsy, but there is little high-quality evidence to confirm the efficacy. This meta-analysis investigated the efficacy and safety of KD in CDKL5-related epilepsy.

Methods

The PubMed, Embase, Web of Science, Cochrane Library, WanFang, CNKI and VIP databases were searched for relevant studies published up to January 1, 2022. Two reviewers independently screened the literature according to inclusion and exclusion criteria and evaluated the bias risk of the included studies. Meta-analysis was performed using Review Manager 5.3 software.

Results

A total of 12 retrospective studies involving 193 patients met the inclusion criteria. Meta-analysis revealed that the definite responder rate to KD in the treatment of CDKL5-related epilepsy was 18.0% [95% CI (0.07, 0.67)], with no statistical heterogeneity among studies (I2 = 0%, P = 0.45). The clinical responder rate was 50.5% [95% CI (0.75, 1.39)], and there was no statistical heterogeneity among all studies (I2 = 46%, P = 0.05). Subgroup analysis showed that there was no significant difference in the clinical responder rate between the two groups with seizure onset age before and after 1 month (P = 0.14). Only one study mentioned adverse reactions, and the incidence of adverse reactions was 78.3% (18/23). Constipation and vomiting were the main manifestations, implying a high incidence of gastrointestinal adverse reactions.

Conclusions

The definite responder rate to KD in CDKL5-related epilepsy was 18%, and the gastrointestinal adverse reactions were probably common in these patients. All the studies included in the meta-analysis were retrospective, and most of them had small sample sizes. Additional high-quality studies are needed to confirm the efficacy and tolerance of KD in CDKL5-related epilepsy.

Exploring the genetic etiology of drug-resistant epilepsy: incorporation of exome sequencing into practice

BACKGROUND

By affecting about 50 million people worldwide, epilepsy is considered a global concern in neurology. Intolerable enough, up to ¼ of all patients do not respond to antiepileptic drugs and have recurring seizures. Therefore, revealing the underlying etiology is quite demanding in a clinical context to improve diagnosis and disease management.

METHODS

Initially, 85 patients suspected of epilepsy underwent thorough clinical and paraclinical evaluation and 24 individuals with drug-resistant epilepsy entered the study. Using whole-exome sequencing, the genetic etiology of drug-resistant epilepsy was investigated and discerned whether this method could facilitate the management of drug-resistant epilepsy through personalized medicine. Eventually, functional annotation was performed and drug-gene interaction networks were constructed to find potential therapeutic targets.

RESULTS

We found eleven novel variants in various genes including IRF2BPL, ST3GAL3, and GPAA1, for which a few epilepsy-related variants are available in public databases. The overall diagnostic yield for likely pathogenic and pathogenic variants and the detection rate of novel variants were 25% and 84.6%, respectively. Based on the results, two patients were considered potential candidates for personalized medicine. The highest number of interaction with drugs was demonstrated for SCN1A, SCN2A, and GRIN2A genes.

CONCLUSIONS

This study highlighted the importance of consanguineous marriage in drug-resistant epilepsy and suggested the possibility of reduced penetrance and variable expressivity in some of the autosomal dominant cases. We also suggest that whole-exome sequencing could facilitate personalized management of drug-resistant epilepsy. Regarding drug-gene interactions, some genes such as SCN1A and SCN2A might serve as therapeutic targets in drug-resistant epilepsy.

Clinical and genetic analysis of nonketotic hyperglycinemia: A case report

BACKGROUND

Nonketotic hyperglycinemia (NKH) is a rare autosomal recessive genetic disorder of abnormal glycine metabolism caused by insufficient activity of the glycine cleavage enzyme system. Glycine is believed to function mainly as an inhibitory neurotransmitter, but it can also act as a co-agonist of the N-methyl-D-aspartate (NMDA) receptor. The accumulation of a large amount of glycine in the brain leads to neuronal and axonal injury via overactivation of NMDA receptors located in the hippocampus, cerebral cortex, olfactory bulb, and cerebellum and to stimulation of the inhibitory function of glycine receptors located in the spinal cord and brain stem, resulting in central apnea, hiccups, and hypotonia in the early stage of the disease.

CASE SUMMARY

The child described in this report had typical clinical manifestations of NKH, such as hiccups, disturbance of consciousness, hypotonia, and convulsions, within the first week after birth. Whole-exome genetic testing revealed that the child had a compound heterozygous mutation, namely, c.395C>A (p.S132X) and c.2182G>A (p.G728R), in the GLDC gene, and he was diagnosed with NKH. For treatment, we administered an oral levetiracetam solution and added topiramate and prednisone for epilepsy control, but the epilepsy remained uncontrollable. Ketogenic diet therapy was started at 6 mo of age, his seizures were significantly reduced, and there were no obvious adverse reactions during ketogenic treatment. Furthermore, we found that with the development of the disease, high levels of serum glycine decreased or even disappeared without intervention, and as the disease progressed, the corpus callosum became dysplastic.

CONCLUSION

This case shows that plasma glycine levels cannot be used to evaluate the prognosis of NKH, that the development of the corpus callosum can be affected by NKH, and that a ketogenic diet may be effective for seizure control in NKH patients.

CDKL5 Deficiency Disorder-Related Epilepsy: A Review of Current and Emerging Treatment

Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a developmental and epileptic encephalopathy with infantile-onset epilepsy. Most individuals with CDD develop refractory epilepsy with multiple seizure types. Management of seizures in CDD remains challenging for clinicians given the highly refractory nature of seizures and the limited number of disease-specific studies that offer a high level of evidence. Epileptic spasms are the most common seizure type in CDD and are more often refractory to standard first-line treatment than are spasms of other etiologies. In other seizure types, the effectiveness of antiseizure medications is limited and wanes over time. Ketogenic diet and palliative surgical treatments have both had mixed results in observational studies. When treating refractory seizures in CDD, we recommend carefully balancing seizure control and treatment-related side effects to optimize each individual's overall quality of life. Clinical trials of medications targeting epilepsy in CDD have been conducted, and additional investigational small molecules, gene therapy, and other disease-modifying therapies are in development for CDD.

Clemizole and Trazodone are Effective Antiseizure Treatments in a Zebrafish Model of STXBP1 Disorder

CRISPR-Cas9-generated zebrafish carrying a 12 base-pair deletion in stxbpb1b, a paralog sharing 79% amino acid sequence identity with human, exhibit spontaneous electrographic seizures during larval stages of development. Zebrafish stxbp1b mutants provide an efficient preclinical platform to test antiseizure therapeutics. The present study was designed to test antiseizure medications approved for clinical use and two recently identified repurposed drugs with antiseizure activity. Larval homozygous stxbp1b zebrafish (4 days post-fertilization) were agarose-embedded and monitored for electrographic seizure activity using a local field recording electrode placed in midbrain. Frequency of ictal-like events was evaluated at baseline and following 45 min of continuous drug exposure (1 mM, bath application). Analysis was performed on coded files by an experimenter blinded to drug treatment and genotype. Phenytoin, valproate, ethosuximide, levetiracetam, and diazepam had no effect on ictal-like event frequency in stxbp1b mutant zebrafish. Clemizole and trazodone decreased ictal-like event frequency in stxbp1b mutant zebrafish by 80% and 83%, respectively. These results suggest that repurposed drugs with serotonin receptor binding affinities could be effective antiseizure treatments. Clemizole and trazodone were previously identified in a larval zebrafish model for Dravet syndrome. Based primarily on these preclinical zebrafish studies, compassionate-use and double-blind clinical trials with both drugs have progressed. The present study extends this approach to a preclinical zebrafish model representing STXBP1-related disorders, and suggests that future clinical studies may be warranted.

Analysis of Factors That May Affect the Effectiveness of Ketogenic Diet Treatment in Pediatric and Adolescent Patients

Purpose. The aim was to find predictors for ketogenic diet (KD) treatment effectiveness. In addition, recognized factors influencing the efficacy of KD were analyzed based on the ILAE (International League Against Epilepsy) proposed Classification and Definition of the Epilepsy Syndromes. Methods. A sample of 42 patients treated with KD were analyzed. The effectiveness of KD was assessed according to the type of diet, the type of seizures, and the known (KE) or undetermined genetic etiology (UNKE). The group of KE consisted of patients with CACNA1S, CHD2, DEPDC5, KIF1A, PIGN, SCN1A, SCN8A, SLC2A1, SYNGAP1 pathogenic variants. The usefulness of the new Classification and Definition of Epilepsy Syndromes proposed by the ILAE was evaluated. Results. KD therapy was effective in 69.05% of cases. No significant correlation was observed with the type of diet used. KE was related to greater effectiveness after KD treatment. KD treatment was most effective in the reduction of non-focal seizures. Considering the ILAE proposed classification, it was found that KD efficacy was higher in patients with simultaneous focal and tonic-clonic seizures compared to patients with only tonic-clonic or focal seizures. Conclusion. The occurrence of focal seizures does not determine the potential ineffectiveness of treatment with a ketogenic diet. A significant efficacy of ketogenic diet treatment was observed in the group of patients with focal and generalized seizures, as well as epileptic and developmental encephalopathies. The etiology of epileptic seizures plays a more significant role. The new classification will make it easier to select patients who can benefit from this form of treatment.

Genome sequencing of 320 Chinese children with epilepsy: a clinical and molecular study

The aim of this study is to evaluate the diagnostic value of genome sequencing in children with epilepsy, and to provide genome sequencing-based insights into the molecular genetic mechanisms of epilepsy to help establish accurate diagnoses, design appropriate treatments and assist in genetic counselling. We performed genome sequencing on 320 Chinese children with epilepsy, and interpreted single-nucleotide variants and copy number variants of all samples. The complete pedigree and clinical data of the probands were established and followed up. The clinical phenotypes, treatments, prognoses and genotypes of the patients were analysed. Age at seizure onset ranged from 1 day to 17 years, with a median of 4.3 years. Pathogenic/likely pathogenic variants were found in 117 of the 320 children (36.6%), of whom 93 (29.1%) had single-nucleotide variants, 22 (6.9%) had copy number variants and two had both single-nucleotide variants and copy number variants. Single-nucleotide variants were most frequently found in SCN1A (10/95, 10.5%), which is associated with Dravet syndrome, followed by PRRT2 (8/95, 8.4%), which is associated with benign familial infantile epilepsy, and TSC2 (7/95, 7.4%), which is associated with tuberous sclerosis. Among the copy number variants, there were three with a length <25 kilobases. The most common recurrent copy number variants were 17p13.3 deletions (5/24, 20.8%), 16p11.2 deletions (4/24, 16.7%), and 7q11.23 duplications (2/24, 8.3%), which are associated with epilepsy, developmental retardation and congenital abnormalities. Four particular 16p11.2 deletions and two 15q11.2 deletions were considered to be susceptibility factors contributing to neurodevelopmental disorders associated with epilepsy. The diagnostic yield was 75.0% in patients with seizure onset during the first postnatal month, and gradually decreased in patients with seizure onset at a later age. Forty-two patients (13.1%) were found to be specifically treatable for the underlying genetic cause identified by genome sequencing. Three of them received corresponding targeted therapies and demonstrated favourable prognoses. Genome sequencing provides complete genetic diagnosis, thus enabling individualized treatment and genetic counselling for the parents of the patients. Genome sequencing is expected to become the first choice of methods for genetic testing of patients with epilepsy.

Genetic testing for the epilepsies: A systematic review

OBJECTIVE

Numerous genetic testing options for individuals with epilepsy have emerged over the past decade without clear guidelines regarding optimal testing strategies. We performed a systematic evidence review (SER) and conducted meta-analyses of the diagnostic yield of genetic tests commonly utilized for patients with epilepsy. We also assessed nonyield outcomes (NYOs) such as changes in treatment and/or management, prognostic information, recurrence risk determination, and genetic counseling.

METHODS

We performed an SER, in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses), using PubMed, Embase, CINAHL, and Cochrane Central through December of 2020. We included studies that utilized genome sequencing (GS), exome sequencing (ES), multigene panel (MGP), and/or genome-wide comparative genomic hybridization/chromosomal microarray (CGH/CMA) in cohorts (n ≥ 10) ascertained for epilepsy. Quality assessment was undertaken using ROBINS-I (Risk of Bias in Non-Randomized Studies of Interventions). We estimated diagnostic yields and 95% confidence intervals with random effects meta-analyses and narratively synthesized NYOs.

RESULTS

From 5985 nonduplicated articles published through 2020, 154 met inclusion criteria and were included in meta-analyses of diagnostic yield; 43 of those were included in the NYO synthesis. The overall diagnostic yield across all test modalities was 17%, with the highest yield for GS (48%), followed by ES (24%), MGP (19%), and CGH/CMA (9%). The only phenotypic factors that were significantly associated with increased yield were (1) the presence of developmental and epileptic encephalopathy and/or (2) the presence of neurodevelopmental comorbidities. Studies reporting NYOs addressed clinical and personal utility of testing.

SIGNIFICANCE

This comprehensive SER, focused specifically on the literature regarding patients with epilepsy, provides a comparative assessment of the yield of clinically available tests, which will help shape clinician decision-making and policy regarding insurance coverage for genetic testing. We highlight the need for prospective assessment of the clinical and personal utility of genetic testing for patients with epilepsy and for standardization in reporting patient characteristics.

Updates on the ketogenic diet therapy for pediatric epilepsy

The ketogenic diet (KD) is a high-fat, low-carbohydrate diet, in which fat, instead of glucose, acts as a major energy source through the production of ketone bodies. The KD was formally introduced in 1921 to mimic the biochemical changes associated with fasting and gained recognition as a potent treatment for pediatric epilepsy in the mid-1990s. Recent clinical and scientific knowledge supports the use of the KD in drug-resistant epilepsy patients for its anti-seizure efficacy, safety, and tolerability. The KD is also receiving growing attention as a potential treatment option for other neurological disorders. This article will review on the recent updates on the KD, focusing on its mechanisms of action, its alternatives, expansion on its use in terms of age groups and different regions in the world, and future issues.

Long-term effectiveness and adverse effects of ketogenic diet therapy in infants with drug-resistant epilepsy treated at a single center in Argentina

INTRODUCTION

Ketogenic diet therapy (KDT) is a metabolic treatment with proven effectiveness for the treatment of drug-resistant epilepsy in children. Although previously not used in infants under 2 years of age, recent studies have shown KDT to be highly effective and well tolerated in infants with epilepsy, especially those with epileptic encephalopathies. Here, we describe the effectiveness and tolerability of the diet in infants up to 2 years of age.

MATERIAL AND METHODS

A prospective study was conducted in a cohort of infants younger than 2 years of age with drug-resistant epilepsy who received the classic ketogenic diet using a specific protocol at a single center in Argentina.

RESULTS

56 infants with treatment-refractory epilepsy were evaluated. The etiology was genetic in 21.4%, structural in 28.6%, unknown in 44.7%, and metabolic in 5.4%. At 3 months, a > 50% decrease in seizure frequency was observed in 35 patients (62.4%), of whom 11 (19.6%) became seizure free. At 6 months, 34 patients (60.7%) had a decrease in seizure frequency of > 50%, of whom 10 (17.8%) were seizure free. At the one-year follow-up, 27 patients (48.2%) had a > 50% decrease in seizure frequency, of whom six (10.7%) were seizure free. At two years, 14 patients (25%) had a > 50% seizure control, of whom four (7.1%) were seizure free. The most common early adverse effects were hypoglycemia and vomiting, while after 1 month and beyond metabolic acidosis, vomiting, and constipation more commonly found. A trend towards a higher rate of acute adverse events in infants younger than 1 year was observed.

CONCLUSIONS

CKD showed to be a useful option in infants with treatment-resistant epilepsy. Adverse effects were common, but not a reason to discontinue the diet. Further studies are necessary to evaluate in which epilepsy syndromes and etiologies KDT is most effective.

Recent aspects of ketogenic diet in neurological disorders

The ketogenic diet (KD) is a high-fat, low-carbohydrate diet, in which fat is used as the primary energy source through the production of ketone bodies (KBs) in place of glucose. The KD was formally introduced in 1921 to mimic the biochemical changes associated with fasting and gained recognition as a potent treatment for pediatric epilepsy in the mid-1990s. The clinical and basic scientific knowledge that supports the anti-seizure efficacy, safety, and feasibility of using the KD in patients with epilepsy is huge. Additionally, the International Ketogenic Diet Study Group’s consensus guidelines provide practical information in 2009 and 2018. The KD is a broad-spectrum therapy for drug resistant epilepsy and is gaining attention as a potential therapy for other neurological disorders. This article will review recent aspects on the use of the KD, including its mechanisms of action, KD alternatives, expanding its use across different age groups and regions, its use as a treatment for other neurologic disorders, and future research subjects.

The relation of etiology based on the 2017 ILAE classification to the effectiveness of the ketogenic diet in drug-resistant epilepsy in childhood

Objective

To investigate the effectiveness and safety of the ketogenic diet (KD) in drug‐resistant epilepsy in childhood in relation to the new 2017 International League Against Epilepsy (ILAE) classification of etiology.

Methods

A consecutive cohort of patients treated with the KD were categorized according to the ILAE classification into known (structural, genetic, metabolic, infectious, and immune‐mediated) and unknown etiology. Primary outcome was the frequency of patients achieving seizure freedom with the KD at 3 months, secondary outcomes were seizure reduction >50% at 3 months, and both seizure freedom and seizure reduction >50% at 6, 12 months, and at last follow‐up (LFU), and adverse effects. Outcomes were compared between etiology groups.

Results

Etiology was known in 70% (129/183). Outcomes did not differ at 3 months (known vs unknown: seizure freedom 28% vs 33%, seizure reduction 62 vs 67%), but seizure freedom was significantly less frequent in known etiology at 6 months (26% vs 43%) and beyond (22% vs 37%). Logistic regression identified duration of epilepsy, number of previous antiseizure medications (ASMs), and age‐appropriate psychomotor development as positive determinants of outcome. Among individual etiology groups, the effectiveness of KD was relatively best for genetic (33% at LFU) and poorest for metabolic etiology (8% at LFU). The small number of patients with infectious and immune‐mediated etiology requires larger numbers in each etiology group to corroborate our results. No differences in type and frequency of adverse effects (in 71%) between etiology groups were observed, requiring medical intervention in 21%.

Significance

The KD was most effective in genetic and unknown etiology, many unknowns probably represent yet unidentified genetic causes. We recommend consequent diagnostic and genetic work‐up to identify etiologies that respond best to the KD. The KD should be offered early to infants with genetic epilepsy before deterioration of epileptic symptoms and of psychomotor development.

Developmental and epileptic encephalopathies: what we do and do not know

Developmental encephalopathies, including intellectual disability and autistic spectrum disorder, are frequently associated with infant epilepsy. Epileptic encephalopathy is used to describe an assumed causal relationship between epilepsy and developmental delay. Developmental encephalopathies pathogenesis more independent from epilepsy is supported by the identification of several gene variants associated with both developmental encephalopathies and epilepsy, the possibility for gene-associated developmental encephalopathies without epilepsy, and the continued development of developmental encephalopathies even when seizures are controlled. Hence, 'developmental and epileptic encephalopathy' may be a more appropriate term than epileptic encephalopathy. This update considers the best studied 'developmental and epileptic encephalopathy' gene variants for illustrative support for 'developmental and epileptic encephalopathy' over epileptic encephalopathy. Moreover, the interaction between epilepsy and developmental encephalopathies is considered with respect to influence on treatment decisions. Continued research in genetic testing will increase access to clinical tests, earlier diagnosis, better application of current treatments, and potentially provide new molecular-investigated treatments.

Ketogenic Diet in Infants with Early-Onset Epileptic Encephalopathy and SCN2A Mutation

Research has shown mutations in the voltage-gated sodium channel gene SCN2A to be associated with developmental delays and infantile seizures in patients with early-onset epileptic encephalopathies (EOEEs). Here, we report the case of an infant with a de novo SCN2A mutation with EOEE who had medically refractory seizures that improved with a ketogenic diet (KD) implemented at an age less than 2 months. On the day of his birth, the infant presented with a pattern of convulsions with dozens of episodes per day. An initial video electroencephalogram revealed poor reactivity of background activity, with multiple partial episodes starting from the right temporal region, and abnormal electrical activity in the right hemisphere. The seizures previously were not controlled with successive therapy with phenobarbital, topiramate, and levetiracetam. Genetic testing revealed the presence of a mutation in the SCN2A gene (c.4425C>G, p.Asn1475Lys). The infant's seizures decreased significantly with a combination of KD and medication. The present case exemplifies the potential for personalized genomics in identifying the etiology of an illness. Furthermore, the KD appears to feasible in infants younger than 2 months and might elicit good responses to EOEE associated with SCN2A mutation.

SCN2A and Its Related Epileptic Phenotypes

Epilepsies due to SCN2A mutations can present with a broad range of phenotypes that are still not fully understood. Clinical characteristics of SNC2A-related epilepsy may vary from neonatal benign epilepsy to early-onset epileptic encephalopathy, including Ohtahara syndrome and West syndrome, and epileptic encephalopathies occurring at later ages (usually within the first 10 years of life). Some patient may present with intellectual disability and/or autism or movement disorders and without epilepsy. The heterogeneity of the phenotypes associated to such genetic mutations does not always allow the clinician to address his suspect on this gene. For this reason, diagnosis is usually made after a multiple gene panel examination through next generation sequencing (NGS) or after whole exome sequencing (WES) or whole genome sequencing (WGS). Subsequently, confirmation by Sanger sequencing can be obtained. Mutations in SCN2A are inherited as an autosomal dominant trait. Most individuals diagnosed with SCN2A–benign familial neonatal-infantile seizures (BFNIS) have an affected parent; however, hypothetically, a child may present SCN2A-BNFNIS as the result of a de novo pathogenic variant. Almost all individuals with SCN2A and severe epileptic encephalopathies have a de novo pathogenic variant. SNC2A-related epilepsies have not shown a clear genotype–phenotype correlation; in some cases, a same variant may lead to different presentations even within the same family and this could be due to other genetic factors or to environmental causes. There is no “standardized” treatment for SCN2A-related epilepsy, as it varies in relation to the clinical presentation and the phenotype of the patient, according to its own gene mutation. Treatment is based mainly on antiepileptic drugs, which include classic wide-spectrum drugs, such as valproic acid, levetiracetam, and lamotrigine. However, specific agents, which act directly modulating the sodium channels activity (phenytoin, carbamazepine, oxcarbamazepine, lamotrigine, and zonisamide), have shown positive result, as other sodium channel blockers (lidocaine and mexiletine) or even other drugs with different targets (phenobarbital).

Effect of the ketogenic diet in excitable tissues

In the past decade, ketogenic diet (KD) has gained some popularity as a potential treatment for a wide range of diseases, including neurological and metabolic disorders, thanks to a beneficial role mainly related to its anti-inflammatory properties. The high-fat and carbohydrate-restricted regimen causes changes in the metabolism, leading, through the β-oxidation of fatty acids, to the hepatic production of ketone bodies (KBs), which are used by many extrahepatic tissues as energy fuels. Once synthetized, KBs are delivered through the systemic circulation to all the tissues of the organism, where they play pleiotropic roles acting directly and indirectly on various targets, and among them ion channels and neurotransmitters. Moreover, they can operate as signaling metabolites and epigenetic modulators. Therefore, it is inappropriate to consider that the KD regimen can improve the patients' clinical condition simply by means of specific and localized effects; rather, it is more correct to think that KBs affect the organism as a whole. In this review, we tried to summarize the recent knowledge of the effects of KBs on various tissues, with a particular attention on the excitable ones, namely the nervous system, heart, and muscles.

Association of early-onset epileptic encephalopathy with involuntary movements - Case series and literature review

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Epileptic-dyskinetic encephalopathies are rare epileptic disorders characterized by EOEE with involuntary movement.

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The presence of involuntary movements in patients with EOEE caused by gene variants may be a key diagnostic symptom.

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Genetic diagnosis is useful and may provide a reference for treatment selection.

Epileptic-dyskinetic encephalopathies are rare epilepsies characterized by early-onset epileptic encephalopathies (EOEEs) with involuntary movement. Herein, we investigated the impact of gene variants in epileptic-dyskinetic encephalopathies. Four independent patients from four families who exhibited involuntary movements were recruited from Tokyo Metropolitan Neurological Hospital. The inclusion criteria were as follows: onset within 1 year after birth, frequent seizures, severe developmental delay and accompanying involuntary movements.

We detected four genetic mutations, including STXBP1, GNAO1, CYFIP2, and SCN8A variants. The involuntary movements were drug-resistant. However, pallidal electrocoagulation followed by gabapentin were partially effective in treating chorea and ballismus of the extremities in patients with GNAO1 variants, and perampanel partially suppressed seizures and involuntary movements in one patient with a SCN8A variant. Movement disorders are common to many neurodevelopmental disorders, including a variety of EOEEs. Although we could not establish a definitive correlation using genetic variants in patients with EOEE and movement disorders, involuntary movements in patients with EOEEs may be a key diagnostic finding. The usage of genetic variants could prove beneficial in the future as more patients are investigated with epileptic-dyskinetic encephalopathies.

Can change in gut microbiota composition be used as a surrogate marker of treatment efficacy of ketogenic diet in patients with drug-resistant epilepsy?

To answer the question posed in the title of the manuscript, we critically examined the connection between ketogenic diet (KD), gut microbiota (GM), and epilepsy. We conclude that although the evidence for a KD-GM-epilepsy link is fairly robust in rodent epilepsy models, it is very hard to draw meaningful conclusions in humans. The limitations of human studies that have investigated the KD-microbiota-epilepsy relationship include small sample size, a heterogeneous patient population with regard to age and epilepsy type, failure to account for the effect of dietary habits, antiseizure drugs (ASDs) and comedications on GM composition, variability in the KD administered and in the duration of the intervention, and different approaches used in sequencing the microbiome. Although alteration in the GM composition may be a potential indicator of responsiveness/resistance to a KD, we need well-designed randomized case-control and cohort studies involving a large number of a fairly homogenous population of patients with epilepsy adjusted to their habitual dietary habits and region of residence before labeling it as a surrogate marker. Research in this direction may also help us to unravel the mysteries of GM-brain axis not only concerning epilepsy but also in other neurological diseases.

A Novel Kv7.3 Variant in the Voltage-Sensing S4 Segment in a Family With Benign Neonatal Epilepsy: Functional Characterization and in vitro Rescue by β-Hydroxybutyrate

Pathogenic variants in KCNQ2 and KCNQ3, paralogous genes encoding Kv7.2 and Kv7.3 voltage-gated K⁺ channel subunits, are responsible for early-onset developmental/epileptic disorders characterized by heterogeneous clinical phenotypes ranging from benign familial neonatal epilepsy (BFNE) to early-onset developmental and epileptic encephalopathy (DEE). KCNQ2 variants account for the majority of pedigrees with BFNE and KCNQ3 variants are responsible for a much smaller subgroup, but the reasons for this imbalance remain unclear. Analysis of additional pedigrees is needed to further clarify the nature of this genetic heterogeneity and to improve prediction of pathogenicity for novel variants. We identified a BFNE family with two siblings and a parent affected. Exome sequencing on samples from both parents and siblings revealed a novel KCNQ3 variant (c.719T>G; p.M240R), segregating in the three affected individuals. The M240 residue is conserved among human Kv7.2-5 and lies between the two arginines (R5 and R6) closest to the intracellular side of the voltage-sensing S₄ transmembrane segment. Whole cell patch-clamp recordings in Chinese hamster ovary (CHO) cells revealed that homomeric Kv7.3 M240R channels were not functional, whereas heteromeric channels incorporating Kv7.3 M240R mutant subunits with Kv7.2 and Kv7.3 displayed a depolarizing shift of about 10 mV in activation gating. Molecular modeling results suggested that the M240R substitution preferentially stabilized the resting state and possibly destabilized the activated state of the Kv7.3 subunits, a result consistent with functional data. Exposure to β-hydroxybutyrate (BHB), a ketone body generated during the ketogenic diet (KD), reversed channel dysfunction induced by the M240R variant. In conclusion, we describe the first missense loss-of-function (LoF) pathogenic variant within the S₄ segment of Kv7.3 identified in patients with BFNE. Studied under conditions mimicking heterozygosity, the M240R variant mainly affects the voltage sensitivity, in contrast to previously analyzed BFNE Kv7.3 variants that reduce current density. Our pharmacological results provide a rationale for the use of KD in patients carrying LoF variants in Kv7.2 or Kv7.3 subunits.

Diet in the Treatment of Epilepsy: What We Know So Far

Epilepsy is a chronic and debilitating neurological disorder, with a worldwide prevalence of 0.5–1% and a lifetime incidence of 1–3%. An estimated 30% of epileptic patients continue to experience seizures throughout life, despite adequate drug therapy or surgery, with a major impact on society and global health. In recent decades, dietary regimens have been used effectively in the treatment of drug-resistant epilepsy, following the path of a non-pharmacological approach. The ketogenic diet and its variants (e.g., the modified Atkins diet) have an established role in contrasting epileptogenesis through the production of a series of cascading events induced by physiological ketosis. Other dietary regimens, such as caloric restriction and a gluten free diet, can also exert beneficial effects on neuroprotection and, therefore, on refractory epilepsy. The purpose of this review was to analyze the evidence from the literature about the possible efficacy of different dietary regimens on epilepsy, focusing on the underlying pathophysiological mechanisms, safety, and tolerability both in pediatric and adult population. We believe that a better knowledge of the cellular and molecular biochemical processes behind the anticonvulsant effects of alimentary therapies may lead to the development of personalized dietary intervention protocols.

Drug-drug and drug-food interactions in an infant with early-onset SCN2A epilepsy treated with carbamazepine, phenytoin and a ketogenic diet

Sodium channel 2 subunit α (SCN2A) mutations cause difficult-to-treat early-onset epilepsy. Effective treatment includes high-dose phenytoin or carbamazepine ± ketogenic diet (KD). We describe an infant with early-onset SCN2A-epilepsy with subtherapeutic carbamazepine concentration during transition from phenytoin treatment to avoid long-term neurotoxicity. The transition from high-dose phenytoin (20 mg kg^-1 d^-1 , concentration: ≥20 mg/L) with KD, to carbamazepine (50-75 mg kg^-1 d^-1 , concentration: 9-12 mg/L) lasted 85 days, which we suspected was due to significant drug-drug and/or drug-food interactions. Model-based analysis of carbamazepine pharmacokinetics quantified significant time- and dose-dependent phenytoin-mediated CYP3A4 induction and carbamazepine concentration-dependent auto-induction (apparent clearance increased up to 2.5/3-fold). Lower carbamazepine concentrations under KD were modelled as decreased relative bioavailability (44%), potentially related to decreased fraction absorbed (unexpected for this lipophilic drug), increased intestinal/hepatic metabolism and/or decreased protein-binding with KD. This suggests importance of carbamazepine-concentration monitoring during KD-introduction/removal and necessity of high carbamazepine doses to achieve therapeutic concentrations, especially in infants treated with high-dose phenytoin.

Efficacy and Safety of a Ketogenic Diet in Children and Adolescents with Refractory Epilepsy-A Review

Epilepsy in the pediatric and adolescent populations is a devastating condition where individuals are prone to recurrent epileptic seizures or changes in behavior or movement that is the direct result of a primary change in the electrical activity in the brain. Although many children with epilepsy will have seizures controlled with antiseizure medications (ASMs), a large percentage of patients are refractory to drug therapy and may consider initiating a ketogenic diet. The term Ketogenic Diet or Ketogenic Diet Therapy (KDT) refers to any diet therapy in which dietary composition results in a ketogenic state of human metabolism. Currently, there are 4 major Ketogenic diet therapies—the classic ketogenic diet (cKD), the modified Atkins diet (MAD), the medium chain triglyceride ketogenic diet (MCTKD) and the low glycemic index treatment (LGIT). The compositions of the 4 main KDTs differ and limited evidence to distinguish the efficacy among different diets currently exists. Although it is apparent that more randomized controlled trials (RCTs) and long-term studies are needed to evaluate efficacy, side effects and individual response to the diet, it is imperative to study and understand the metabolic profiles of patients with epilepsy in order to isolate which dietary restrictions are necessary to maximize clinical benefit.

The ketogenic diet for infants: How long can you go?

PURPOSE

Ketogenic diets (KD) are high-fat, low-carbohydrate therapies, established in the treatment for drug-resistant epilepsy in childhood since the 1920ies. This review focuses on the use of ketogenic diet therapies in young childhood with an emphasis on the most recent advances.

FINDINGS

The KD has been used effectively and safely in childhood, and has increasingly been offered in infancy during the last decade. The introduction of a KD is recommended with a fixed fat/ non-fat ratio of 3:1, modified if necessary. In infants the KD is initiated without fasting and fluid restriction and with a shorter treatment duration than in older children. Twenty studies that also included infants below 1 year of age are available. When the KD is used early and in an approach based on syndromes and etiology, seizure freedom is achieved and maintained more often than when used as last ressort. In infants with genetic causes already recognized in early infancy, the KD has shown to be even more effective. Most frequent adverse effects in infancy include emesis, hypoglycemia, food/ liquid refusal and constipation which are mostly transient and resolvable by dietary adjustments. Promising data on the inclusion of expressed breast milk to the KD and maintaining actual breastfeeding while on the KD have shown that complete weaning from breast-feeding is not necessary and inclusion of breast milk as well as breastfeeding should be encouraged.

SUMMARY

The ketogenic diet is a versatile therapy, and effective and safe in its use in infancy. There is growing evidence and guidelines that specify indications where the KD should be used early.

The evolving indications of KD therapy

Despite the rapid increase of clinical and basic-science knowledge on ketogenic diet therapies over the past years, it has not always been easy to determine the adequate indications of this treatment. Over the nearly 100 years of use, from being a last resource in the therapeutic algorithm, the diet has become one of the four main treatments for patients with difficult-to-control epilepsy together with antiepileptic drugs, surgery, and vagus nerve stimulation. The use of the diet has also changed. The current paper will briefly discuss the history of the diet together with a review of the literature regarding its most important indications and how they have evolved. The concept of the importance of defining the type of seizure, type of syndrome, and etiology in the selection of patients and timing of diet initiation has been gaining importance. This paper explores how the indications of the diet changed together with the shifting focus of epilepsy teams towards its use in different types of epilepsy and epilepsy syndromes and according to etiologies and as an alternative option in refractory and superrefractory status epilepticus.

Muscle and brain sodium channelopathies: genetic causes, clinical phenotypes, and management approaches

Voltage-gated sodium channels are essential for excitability of skeletal muscle fibres and neurons. An increasing number of disabling or fatal paediatric neurological disorders linked to mutations of voltage-gated sodium channel genes are recognised. Muscle phenotypes include episodic paralysis, myotonia, neonatal hypotonia, respiratory compromise, laryngospasm or stridor, congenital myasthenia, and myopathy. Evidence suggests a possible link between sodium channel dysfunction and sudden infant death. Increasingly recognised phenotypes of brain sodium channelopathies include several epilepsy disorders and complex encephalopathies. Together, these early-onset muscle and brain phenotypes have a substantial morbidity and a considerable mortality. Important advances in understanding the pathophysiological mechanisms underlying these channelopathies have helped to identify effective targeted therapies. The availability of effective treatments underlines the importance of increasing clinical awareness and the need to achieve a precise genetic diagnosis. In this Review, we describe the expanded range of phenotypes of muscle and brain sodium channelopathies and the underlying knowledge regarding mechanisms of sodium channel dysfunction. We also outline a diagnostic approach and review the available treatment options.

Novel CDKL5 mutations were found in patients in China: retrospective investigation in cases of CDKL5-related disorders

Objective

CDKL5-related disorders (CDD) is an epileptic encephalopathy resulted of gene mutations of CDKL5. This study aimed to explore the development process of CDD and to expand its mutation spectrum.

Methods

Clinic datawas collected about three infantile epileptic encephalopathy cases diagnosed at Xinhua Hospital Affiliated to Shanghai Jiaotong University, School of Medicine. Next generation sequencing technology was used to find three de novo mutations of CDKL5. We searched published literatures about CDKL5 in pubmed and made an analysis about our clinic data and the related literatures.

Results

The three patients were all girls. Their average onset age of seizures was around 2 months, and all of them have intractable epileptic seizures, severe intellectual disability, and hypotension. Among them, two presented infantile spasm and high arrhythmia in EEG, and the other manifested clonic seizure and broad epileptiform discharge in EEG. Extracerebral space widening in cranial MRIs was demonstrated in two cases. Visual evoked potential was abnormal in two cases. Seizures were resistant to all kinds of antiepileptic drugs (AEDs). Gene tests showed three de novo mutations of CDKL5: one was a truncated mutation (c.2254A > T,P.R752X, stop279), which was pathogenic according to the ACMG guide, the other two were missense mutations (c.377G > T,p.Cys126Phe) and a frameshift mutation (c.362-362insG(p.Ala122GlyfsTer7), which were likely pathogenic according to the ACMG.

Conclusions

All three de novo mutations are first reported. Based on the combined related literature and the manifestations observed, we diagnosed the three children as CDKL5-related disorders, and concluded that the de novo CDKL5 mutations are the reason for their epilepsy.

CDKL5 Deficiency Disorder-A Complex Epileptic Encephalopathy

CDKL5 deficiency disorder (CDD) is a complex of clinical symptoms resulting from the presence of non-functional CDKL5 protein, i.e., serine-threonine kinase (previously referred to as STK9), or its complete absence. The clinical picture is characterized by epileptic seizures (that start within the first three months of life and most often do not respond to pharmacological treatment), epileptic encephalopathy secondary to seizures, and retardation of psychomotor development, which are often observed already in the first months of life. Due to the fact that CDKL5 is located on the X chromosome, the prevalence of CDD among women is four times higher than in men. However, the course is usually more severe among male patients. Recently, many clinical centers have analyzed this condition and provided knowledge on the function of CDKL5 protein, the natural history of the disease, therapeutic options, and their effectiveness and prognosis. The International CDKL5 Disorder Database was established in 2012, which focuses its activity on expanding knowledge related to this condition and disseminating such knowledge to the families of patients.

Recent advances in treatment of epilepsy-related sodium channelopathies

Voltage-gated sodium channels (VGSCs) play a crucial role in generation of action potentials. Pathogenic variants in the five human brain expressed VGSC genes, SCN1A, SCN2A, SCN3A, SCN8A and SCN1B have been associated with a spectrum of epilepsy phenotypes and neurodevelopmental disorders. In the last decade, next generation sequencing techniques have revolutionized the way we diagnose these channelopathies, which is paving the way towards precision medicine. Knowing the functional effect (Loss-of-function versus Gain-of-function) of a variant is not only important for understanding the underlying pathophysiology, but it is particularly crucial to orient therapeutic decisions. Here we provide a review of the literature dealing with treatment options in epilepsy-related sodium channelopathies, including the current and emerging medications.

The Efficacy of Ketogenic Diet in 60 Chinese Patients With Dravet Syndrome

Objective: To evaluate the efficacy and safety of ketogenic diet (KD) in patients with Dravet syndrome (DS). Methods: 60 DS patients receiving treatment of KD for more than 12 weeks from 2009 to 2018 were analyzed retrospectively. Modified Johns Hopkins protocol was used to initiate KD. Seizure frequency, electroencephalogram (EEG), cognition, language, and motor function of the patients were assessed. Side effects were monitored and adjusted accordingly. SPSS 23.0 software was used for all statistical analysis. Results: In total, 60 DS patients (34 boys, 26 girls) received treatment of KD for more than 12 weeks, and among them 41 (68.3%) patients remained on the diet for more than 24 weeks, 22 (36.7%) patients for more than 48 weeks. Seizures in 35 patients (58.3%) were reduced by over 50% at 12 weeks, and the KD effect was observed within 2 weeks in most of them. At 24 weeks, 61.1% (25/41) of the patients had a >50% seizure reduction. At 48 weeks, 77.3% (17/22) had an over 50% reduction in their seizure frequency. With the treatment of KD in the 60 DS patients, 10 patients had ever been seizure free for 12 months to 24 months (The median duration was 20 months). In 10 KD-effective patients, the background rhythm of their EEG showed obvious improvement, and interictal epileptic discharges decreased significantly. Cognitive function of 22 patients was improved. Language progressed in 14 patients. Motor function was improved in 13 patients. The efficacy of KD in DS patients did not correlate with the seizure onset age, the starting age of KD treatment, the SCN1A mutation and the numbers of antiepileptic drugs combined with KD treatment. The main adverse reactions of KD in the treatment process were gastrointestinal symptoms and metabolic disorders. Conclusions: KD treatment in DS patients has many advantages, including working rapidly, being effective in more than half of the DS patients and tolerable adverse reactions. Pharmoco-resistant DS patients are suggested to receive KD treatment.

The Ketogenic and Modified Atkins Diet Therapy for Children With Refractory Epilepsy of Genetic Etiology

BACKGROUND

The ketogenic diet is an accepted treatment modality in refractory childhood epilepsy. In this study, we analyzed the efficacy and tolerability of the ketogenic and modified Atkins diets in children with refractory epilepsy of genetic etiology and studied the effect of the diet on seizure frequency.

METHODS

The records of children with a genetic etiology for refractory epilepsy treated with ketogenic and modified Atkins diet between September 2005 and July 2016 were reviewed. We documented age of seizure and diet onset, seizure characteristics, and specific genetic etiology. The proportion of children remaining on the diet and responder rates (greater than 50% seizure reduction) were noted at one, three, six, 12, and 24 months after diet initiation. Tolerability and safety profile were also recorded.

RESULTS

Fifty-nine children with a genetic etiology (63% females, median age at diet onset 2.2 years) were initiated on the diet at our center. Fifty-three (90%) were started on a traditional ketogenic diet, whereas six started a modified Atkins diet. The adverse events at the initiation of diet were vomiting (24%), hypoglycemia (15%), and refusal to feed (11%). Three children stopped the diet before discharge because of poor compliance, severe reflux, and ketoacidosis (n = 1 each). The proportion of children remaining on the diet at one, three, six, 12, and 24 months was 95%, 86%, 69%, 64%, and 47%. The responder rates were 63%, 61%, 54%, 53%, and 41% at one, three, six, 12, and 24 months, respectively.

CONCLUSIONS

The ketogenic diet is an effective treatment modality in children with refractory epilepsy of genetic etiology.

Ketogenic diet as a successful early treatment modality for SCN2A mutation

SCN2A mutations have been described in a very broad spectrum of clinical phenotypes including benign (familial) neonatal/infantile seizures and early infantile epileptic encephalopathies (EIEE) as Ohtahara syndrome (OS), Dravet syndrome (DS), epilepsy of infancy with migrating focal seizures and West syndrome (WS). Treatment modalities for epilepsy caused by SCN2A mutations mainly consist of sodium channel blockers but ketogenic diet (KD) is also considered as an option of treatment for intractible seizures caused by SCN2A mutations. Because of the wide nature of the heterogeneity of mutations related to SCN2A gene, the clinical phenotypes vary in severity and treatment response to KD has been reported to be controversial. We present a patient diagnosed with OS associated with a novel SCN2A mutation (c.408G > A, p.Met136lle; OMIM®: 182390) who had a complete resolution of seizures and EEG abnormalities with KD commenced at 39 days of age. As far as we are aware our case is the youngest patient with SCN2A mutation treated with KD with complete resolution of epilepsy at an early age and has been seizure free of antiepileptic medications for a long duration.