Gastrointestinal Symptoms and Channelopathy-Associated Epilepsy

Feeding Difficulties and Gastrostomy in Dravet Syndrome: A UK-Wide Survey and 2-Center Experience

Background and Objectives

Dravet syndrome (DS) is one of the most common monogenic epilepsies. Alongside the core seizure and developmental phenotypes, problems with appetite, swallowing, and weight loss are frequently reported, necessitating gastrostomy in some. We explored the burden of feeding difficulties and need for gastrostomy across 3 DS populations in the United Kingdom. We document caregiver opinion and postgastrostomy outcomes, and provide guidance regarding feeding issues and gastrostomy in DS.

Methods

A retrospective, observational study was conducted; data were collected from medical records of 124 individuals with DS attending clinics at the National Hospital for Neurology and Neurosurgery, and Great Ormond Street Hospital, and from 65 DS caregiver responses to a UK-wide survey.

Results

In total, 64 of 124 (52%) had at least 1 feeding difficulty; 21 of 124 (17%) had a gastrostomy, and gastrostomy was being considered in 5%; the most common reasons for gastrostomy were poor appetite (81%) and weight loss/failure to gain weight (71%). Median age at gastrostomy was 17 years (range 2.5-59). Multivariate analyses identified several factors that in combination contributed to risk of feeding difficulties and gastrostomy, including treatment with several antiseizure medications (ASMs), of which stiripentol made a unique contribution to risk of gastrostomy (p = 0.048, odds ratio 3.20, 95% CI 1.01-10.16). Preinsertion, 88% of caregivers were worried about the gastrostomy, with concerns across a range of issues. Postgastrostomy, 88% of caregivers were happy that their child had the gastrostomy, and >90% agreed that the gastrostomy ensured medication compliance, that their child's overall health was better, and that quality of life improved.

Discussion

Feeding difficulties are common in DS, and 17% require a gastrostomy to address these. Risk factors for feeding difficulties in DS are unknown, but ASMs may play a role. There is a high level of caregiver concern regarding gastrostomy preprocedure; however, postgastrostomy caregiver opinion is positive. Feeding difficulties should be proactively sought during review of people with DS, and the potential need for gastrostomy should be discussed.

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.

Prevalence, types, and risk factors of functional gastrointestinal diseases in Hainan Province, China

To investigate the prevalence, types, and risk factors of functional gastrointestinal diseases (FGIDs) in Hainan Province, China, in order to provide insights for future prevention and treatment strategies. A questionnaire survey was conducted from July 2022 to May 2023, using stratified sampling to sample local residents in five cities (20 townships) in Hainan Province. Out of 2057 local residents surveyed, 659 individuals (32.0%) reported experiencing at least one FGID. The most prevalent FGIDs were functional dyspepsia (FD) (10.7%), functional constipation (FC) (9.3%), irritable bowel syndrome (IBS) (6.8%), functional bloating (2.2%), belching disorder (2.2%), functional diarrhea (FDr) (1.5%), functional heartburn (1.5%), and fecal incontinence (0.98%). The study revealed significant associations between FGIDs and factors such as age, sleep quality, anxiety, smoking, alcohol consumption, and the consumption of pickled food (P < 0.05). Older age, poor sleep quality, anxiety, and the consumption of pickled food were identified as independent risk factors for the prevalence of FGIDs (P < 0.05). In Hainan Province, the overall prevalence of FGIDs was found to be 32.0%, with higher prevalences of FC and FD. Older age, poor sleep quality, anxiety, and the consumption of pickled food were identified as risk factors for FGIDs.

Clinical and Genetic Features of Dravet Syndrome: A Prime Example of the Role of Precision Medicine in Genetic Epilepsy

Dravet syndrome (DS), also known as severe myoclonic epilepsy of infancy, is a rare and drug-resistant form of developmental and epileptic encephalopathies, which is both debilitating and challenging to manage, typically arising during the first year of life, with seizures often triggered by fever, infections, or vaccinations. It is characterized by frequent and prolonged seizures, developmental delays, and various other neurological and behavioral impairments. Most cases result from pathogenic mutations in the sodium voltage-gated channel alpha subunit 1 (SCN1A) gene, which encodes a critical voltage-gated sodium channel subunit involved in neuronal excitability. Precision medicine offers significant potential for improving DS diagnosis and treatment. Early genetic testing enables timely and accurate diagnosis. Advances in our understanding of DS's underlying genetic mechanisms and neurobiology have enabled the development of targeted therapies, such as gene therapy, offering more effective and less invasive treatment options for patients with DS. Targeted and gene therapies provide hope for more effective and personalized treatments. However, research into novel approaches remains in its early stages, and their clinical application remains to be seen. This review addresses the current understanding of clinical DS features, genetic involvement in DS development, and outcomes of novel DS therapies.

Gastrointestinal Dysfunction in Genetically Defined Neurodevelopmental Disorders

Gastrointestinal symptoms are common in most forms of neurodevelopment disorders (NDDs) such as in autism spectrum disorders (ASD). The current patient-reported outcome measures with validated questionnaires used in the general population of children without NDDS cannot be used in the autistic individuals. We explore here the multifactorial pathophysiology of ASD and the role of genetics and the environment in this disease spectrum and focus instead on possible diagnostics that could provide future objective insight into the connection of the gut-brain-microbiome in this disease entity. We provide our own data from both humans and a zebrafish model of ASD called Phelan-McDermid Syndrome. We hope that this review highlights the gaps in our current knowledge on many of these profound NDDs and that it provides a future framework upon which clinicians and researchers can build and network with other interested multidisciplinary specialties.

The Role of Ion Channels in Functional Gastrointestinal Disorders (FGID): Evidence of Channelopathies and Potential Avenues for Future Research and Therapeutic Targets

Several gastrointestinal (GI) tract abnormalities, including visceral hypersensitivity, motility, and intestinal permeability alterations, have been implicated in functional GI disorders (FGIDs). Ion channels play a crucial role in all the functions mentioned above. Hormones and natural molecules modulate these channels and represent targets of drugs and bacterial toxins. Mutations and abnormal functional expression of ion channel subunits can lead to diseases called channelopathies. These channelopathies in gastroenterology are gaining a strong interest, and the evidence of co-relationships is increasing. In this review, we describe the correlation status between channelopathies and FGIDs. Different findings are available. Among others, mutations in the ABCC7/CFTR gene have been described as a cause of constipation and diarrhea. Mutations of the SCN5A gene are instead associated with irritable bowel syndrome. In contrast, mutations of the TRPV1 and TRPA genes of the transient receptor potential (TRP) superfamily manifest hypersensitivity and visceral pain in sensory nerves. Recently, mice and humans affected by Cantu syndrome (CS), which is associated with the mutations of the KCNJ8 and ABCC9 genes encoding for the Kir6.1 and SUR2 subunits, showed dysfunction of contractility throughout the intestine and death in the mice after the weaning on solid food. The discovery of a correlation between channelopathies and FIGD opens new avenues for discovering new direct drug targets for specific channelopathies, leading to significant implications for diagnosing and treating functional GI diseases.

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.

Assessing epilepsy-related autonomic manifestations: Beyond cardiac and respiratory investigations

The Autonomic Nervous System (ANS) regulates many critical physiological functions. Its control relies on cortical input, especially limbic areas, which are often involved in epilepsy. Peri-ictal autonomic dysfunction is now well documented, but inter-ictal dysregulation is less studied. In this review, we discuss the available data on epilepsy-related autonomic dysfunction and the objective tests available. Epilepsy is associated with sympathetic-parasympathetic imbalance and a shift towards sympathetic dominance. Objective tests report alterations in heart rate, baroreflex function, cerebral autoregulation, sweat glands activity, thermoregulation, gastrointestinal and urinary function. However, some tests have found contradictory results and many tests suffer from a lack of sensitivity and reproducibility. Further study on interictal ANS function is required to further understand autonomic dysregulation and the potential association with clinically-relevant complications, including risk of Sudden Unexpected Death In Epilepsy (SUDEP).

Improving the effects of ketogenic diet therapy in children with drug-resistant epilepsy

PURPOSE

To evaluate the retention rate, efficacy, and safety of ketogenic diet therapy for drug-resistant epilepsy in children and compare the results with those of a previous cohort at our institution.

METHODS

A total of 634 children with drug-resistant epilepsy were included in this retrospective study. Patients were categorized into two groups. The previous cohort was included as a control group and included 317 children assessed between 2004 and 2011, whereas the current group included 317 children assessed between 2015 and 2019. The control group was provided care as usual, and the current group additionally adopted the goal and long-term management strategy. Outcomes were measured with respect to retention rate, seizure reduction, and adverse reaction.

RESULTS

Patient demographics were consistent between both cohorts. Compared to the past ten years, the retention rate significantly increased over time (3 months: 62.8% vs. 82.0%, p <0.001; 6 months: 42.0% vs. 60.6%, p <0.001; 12 months: 24.3% vs. 34.1%, p = 0.007), and the response rate was significantly improved (3 months: 35.0% vs. 55.5%, p <0.001; 6 months: 26.2% vs. 43.2%, p <0.001; 12 months: 18.6% vs. 31.5%, p <0.001). Constipation (n = 79, 24.9%) was the most common side effect in the current cohort. Food refusal and hypoproteinaemia reduced to 3.5% and 0.9%, respectively.

CONCLUSION

Goal and long-term management is effective for ketogenic diet therapy, which significantly improved the ketogenic diet retention rate, efficacy, and incidence of adverse reactions. This strategy has promising applicability in ketogenic diet therapy.

CLINICAL REGISTRATION

ChiCTR-IIR-16,008,342.