International Consensus Recommendations for the Assessment and Management of Individuals With CDKL5 Deficiency Disorder

Early Developmental Intervention and Enriched Environment in CDKL5 Developmental and Epileptic Encephalopathy: A Case Report

Objectives

CDKL5 developmental and epileptic encephalopathy (CDKL5-DEE) is a rare X-linked dominant genetic disorder. Family-centered Early Intervention (EI) programs, which promote axonal plasticity and synaptic reorganization through exposure to an enriched environment, should be integrated into clinical practice. However, there is presently a dearth of dedicated EI protocols for patients with CDKL5-DEE and cerebral visual impairment (CVI).

Methods

We present a girl with a deletion of the CDKL5 gene (MIM*300203). At the age of 2 months, the child presented with severe epilepsy. The neurologic examination was abnormal, and she had severe CVI. At the first assessment, at 5 months old, her Developmental Quotient (DQ) on the Griffiths Mental Developmental Scales III (GMDS-III) was equivalent to 3-month-old skills (95% CI). The child was enrolled in an EI program for 6 months.

Results

At 12 months of age, the DQ score was 91. There has been improvement in the neurovisual functions. The findings from the scales show a gradual improvement in neuromotor and psychomotor development, which is in contrast to the expected outcome of the disease.

Discussion

The case study shows that a family-centered EI and prompt assessment of CVI can promote and enhance neurodevelopment.

CDKL5 deficiency disorder: At the intersection between Rett syndrome and developmental epileptic encephalopathies

This commentary is on the original articles by Wong et al. and Daniels et al. on pages 469–482 and 456–468 of this issue.

Growth patterns in individuals with CDKL5 deficiency disorder

AIM

To compare growth in individuals with cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder with population norms and to investigate the effect of gastrostomy on growth.

METHOD

The longitudinal study included 353 individuals from the International CDKL5 Disorder Database with any anthropometric measurement in baseline and/or follow-up questionnaires. The British 1990 growth reference was used to determine the age- and sex-standardized z-score. Repeated cross-sectional data were fitted using a Gaussian linear regression model with generalized estimating equations.

RESULTS

All growth parameters were below the general population norm (mean z-scores: weight -0.97, height -0.65, body mass index [BMI] -0.81, head circumference -2.12). The disparity was particularly pronounced for all anthropometric measurements after 4 years of age except for BMI. Moreover, individuals with gastrostomy placement were shown to have a larger decrease than those without.

INTERPRETATION

In addition to weight, height, and BMI, head circumference was also compromised in this disorder. Microcephaly could be considered a helpful diagnostic feature, especially in adults. Any benefit of gastrostomy on weight and BMI was mainly seen in the early years.

Improving care for rare genetic neurodevelopmental disorders: A systematic review and critical appraisal of clinical practice guidelines using AGREE II

PURPOSE

Rare genetic neurodevelopmental disorders associated with intellectual disability require lifelong multidisciplinary care. Clinical practice guidelines may support healthcare professionals in their daily practice, but guideline development for rare conditions can be challenging. In this systematic review, the characteristics and methodological quality of internationally published recommendations for this population are described to provide an overview of current guidelines and inform future efforts of European Reference Network ITHACA (Intellectual disability, TeleHealth, Autism, and Congenital Anomalies).

METHODS

MEDLINE, Embase, and Orphanet were systematically searched to identify guidelines for conditions classified as "rare genetic intellectual disability" (ORPHA:183757). Methodological quality was assessed using the Appraisal of Guidelines, Research, and Evaluation II tool.

RESULTS

Seventy internationally published guidelines, addressing the diagnosis and/or management of 28 conditions, were included. The methodological rigor of development was highly variable with limited reporting of literature searches and consensus methods. Stakeholder involvement and editorial independence varied as well. Implementation was rarely addressed.

CONCLUSION

Comprehensive, high-quality guidelines are lacking for many rare genetic neurodevelopmental disorders. Use and transparent reporting of sound development methodologies, active involvement of affected individuals and families, robust conflict of interest procedures, and attention to implementation are vital for enhancing the impact of clinical practice recommendations.

Gut microbiota profile in CDKL5 deficiency disorder patients

CDKL5 deficiency disorder (CDD) is a neurodevelopmental condition characterized by global developmental delay, early-onset seizures, intellectual disability, visual and motor impairments. Unlike Rett Syndrome (RTT), CDD lacks a clear regression period. Patients with CDD frequently encounter gastrointestinal (GI) disturbances and exhibit signs of subclinical immune dysregulation. However, the underlying causes of these conditions remain elusive. Emerging studies indicate a potential connection between neurological disorders and gut microbiota, an area completely unexplored in CDD. We conducted a pioneering study, analyzing fecal microbiota composition in individuals with CDD (n = 17) and their healthy relatives (n = 17). Notably, differences in intestinal bacterial diversity and composition were identified in CDD patients. In particular, at genus level, CDD microbial communities were characterized by an increase in the relative abundance of Clostridium_AQ, Eggerthella, Streptococcus, and Erysipelatoclostridium, and by a decrease in Eubacterium, Dorea, Odoribacter, Intestinomonas, and Gemmiger, pointing toward a dysbiotic profile. We further investigated microbiota changes based on the severity of GI issues, seizure frequency, sleep disorders, food intake type, impairment in neuro-behavioral features and ambulation capacity. Enrichment in Lachnoclostridium and Enterobacteriaceae was observed in the microbiota of patients with more severe GI symptoms, while Clostridiaceae, Peptostreptococcaceae, Coriobacteriaceae, Erysipelotrichaceae, Christensenellaceae, and Ruminococcaceae were enriched in patients experiencing daily epileptic seizures. Our findings suggest a potential connection between CDD, microbiota and symptom severity. This study marks the first exploration of the gut-microbiota-brain axis in subjects with CDD. It adds to the growing body of research emphasizing the role of the gut microbiota in neurodevelopmental disorders and opens doors to potential interventions that target intestinal microbes with the aim of improving the lives of patients with CDD.

Providing quality care for people with CDKL5 deficiency disorder: A European expert panel opinion on the patient journey

Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a developmental and epileptic encephalopathy caused by variants in the CDKL5 gene. The disorder is characterized by intractable early-onset seizures, severe neurodevelopmental delay, hypotonia, motor disabilities, cerebral (cortical) visual impairment and microcephaly. With no disease-modifying therapies available for CDD, treatment is symptomatic with an initial focus on seizure control. Another unmet need in the management of people with CDD is the lack of evidence to aid standardized care and guideline development. To address this gap, experts in CDD and representatives from patient advocacy groups from Denmark, Finland, France, Germany, Italy, Poland, Spain, and the United Kingdom convened to form an Expert Working Group. The aim was to provide an expert opinion consensus on how to ensure quality care in routine clinical practice within the European setting, including in settings with limited experience or resources for multidisciplinary care of CDD and other developmental and epileptic encephalopathies. By means of one-to-one interviews around the current treatment landscape in CDD, insights from the Expert Working Group were collated and developed into a Europe-specific patient journey for individuals with CDD, which was later validated by the group. Further discussions followed to gain consensus of opinions on challenges and potential solutions for achieving quality care in this setting. The panel recognized the benefit of early genetic testing, a holistic personalized approach to seizure control (taking into consideration various factors such as concomitant medications and comorbidities), and age- and comorbidity-dependent multidisciplinary care for optimizing patient outcomes and quality of life. However, their insights and experiences also highlighted much disparity in management approaches and resources across different European countries. Development of standardized European recommendations is required to align realistic diagnostic criteria, treatment goals, and management approaches that can be adapted for different settings. PLAIN LANGUAGE SUMMARY: Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a rare condition caused by a genetic mutation with a broad range of symptoms apparent from early childhood, including epileptic seizures that do not respond to medication and severe delays in development. Due to the lack of guidance on managing CDD, international experts and patient advocates discussed best practices in the care of people with CDD in Europe. The panel agreed that early testing, a personalized approach to managing seizures, and access to care from different disciplines are beneficial. Development of guidelines to ensure that care is standardized would also be valuable.

CDKL5 Deficiency Disorder: Some Lessons Learned 20 Years After the First Description

Loss of function variants in the Cyclin-dependent kinase-like 5 gene (CDKL5) causes CDKL5 deficiency disorder (CDD). Most cases of CDD are due to a de novo missense or truncating variants. The CDKL5 gene was discovered in 1998 as part of the genomic mapping of the chromosome Xp22 region that led to the discovery of the serine-threonine kinases STK9. Since then, there have been significant advancements in the description of the disease in humans, the understanding of the pathophysiology, and the management of the disease. There have been many lessons learned since the initial description of the condition in humans in 2003. In this article, we will focus on pathophysiology, clinical manifestations, with particular focus on seizures because of its relevance to the medical practitioners and researchers and guidelines for management. We finalize the manuscript with the voice of the parents and caregivers, as discussed with the 2019 meeting with the Food and Drug Administration.

Health care concerns in parents of children with different genetic developmental and epileptic encephalopathies: A qualitative study

AIM

To describe the experiences and unmet medical care needs of a group of parents of children with developmental and epileptic encephalopathies (DEEs) caused by the SCN1A, KCNQ2, CDKL5, PCDH19, and GNAO1 variants.

METHOD

A qualitative descriptive study was conducted. Participants were recruited using purposeful sampling. The inclusion criteria consisted of parents of children with DEEs caused by the SCN1A, KCNQ2, CDKL5, PCDH19, or GNAO1 variants, aged between 4 and 10 years old. In total, 21 parents were included. Data were acquired via researcher field notes and in-depth interviews. A thematic analysis was performed.

RESULTS

Three main themes were identified: (1) managing symptoms: epileptic seizures are experienced with great uncertainty and are accompanied by cognitive, behavioural, and motor symptoms; (2) accepting treatment: the ideal medication regimen is a challenge and the decision to withdraw or start a new therapy falls on the parents; and (3) therapeutic relationship and medical care: behaviours related to the health professional can hinder the therapeutic relationship with the parents. Parents are apprehensive about going to the emergency department.

INTERPRETATION

Professionals in emergency departments should acquire better knowledge of DEEs, welcome parents, and improve treatment for the children. The results of this study can serve as a starting point for a roadmap of relevant caregiver-reported outcomes in DEEs, to be implemented with new clinical trials and aetiology-targeted therapies.

WHAT THIS PAPER ADDS

Epileptic seizures are the symptom that is most experienced and feared by parents. The medication regime has no defined protocol and the decision to withdraw a medication is frequently left to parents.

Preocupaciones sobre la atención sanitaria en progenitores de niños con diferentes encefalopatías epilépticas genéticas del desarrollo: Un estudio cualitativo

Objetivo

Describir las experiencias y las necesidades de atención médica de un grupo de progenitores de niños con encefalopatías epilépticas y del desarrollo (EED) causadas por las variantes SCN1A, KCNQ2, CDKL5, PCDH19 y GNAO1.

Método

Se realizó un estudio cualitativo descriptivo. Los participantes fueron reclutados mediante un muestreo intencional. Los criterios de inclusión consistieron en progenitores de niños con EED causadas por las variantes SCN1A, KCNQ2, CDKL5, PCDH19 o GNAO1, con edades comprendidas entre los 4 y los 10 años. En total, se incluyeron 21 progenitores. Los datos se obtuvieron mediante entrevistas en profundidad y notas de campo del investigador. Se realizó un análisis temático.

Resultados

Se identificaron tres temas principales: (1) Manejando los síntomas, las crisis epilépticas se viven con gran incertidumbre, y se acompañan de síntomas cognitivos, conductuales y motores que limitan la vida del niño; b) Aceptando el tratamiento, la pauta de la medicación idónea es un reto, la decisión de retirar o comenzar una nueva terapia recae en los progenitores; y c) Relación terapéutica y atención médica, existen comportamientos y acciones del profesional que facilitan o dificultan la relación terapéutica con los progenitores. Acudir al servicio de urgencias es vivido con recelo por los progenitores.

Interpretación

Los profesionales de los servicios de urgencias deben conocer mejor las EED, acoger a los progenitores y mejorar el tratamiento de los niños. Los resultados de este estudio pueden servir como punto de partida para una hoja de ruta de los resultados relevantes reportados por los cuidadores de las EED, a implementar nuevos ensayos clínicos y terapias dirigidas a la etiología.

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New GABA-Targeting Therapies for the Treatment of Seizures and Epilepsy: I. Role of GABA as a Modulator of Seizure Activity and Recently Approved Medications Acting on the GABA System

γ-Aminobutyric acid (GABA) is the most prevalent inhibitory neurotransmitter in the mammalian brain and has been found to play an important role in the pathogenesis or the expression of many neurological diseases, including epilepsy. Although GABA can act on different receptor subtypes, the component of the GABA system that is most critical to modulation of seizure activity is the GABAA-receptor-chloride (Cl-) channel complex, which controls the movement of Cl- ions across the neuronal membrane. In the mature brain, binding of GABA to GABAA receptors evokes a hyperpolarising (anticonvulsant) response, which is mediated by influx of Cl- into the cell driven by its concentration gradient between extracellular and intracellular fluid. However, in the immature brain and under certain pathological conditions, GABA can exert a paradoxical depolarising (proconvulsant) effect as a result of an efflux of chloride from high intracellular to lower extracellular Cl- levels. Extensive preclinical and clinical evidence indicates that alterations in GABAergic inhibition caused by drugs, toxins, gene defects or other disease states (including seizures themselves) play a causative or contributing role in facilitating or maintaning seizure activity. Conversely, enhancement of GABAergic transmission through pharmacological modulation of the GABA system is a major mechanism by which different antiseizure medications exert their therapeutic effect. In this article, we review the pharmacology and function of the GABA system and its perturbation in seizure disorders, and highlight how improved understanding of this system offers opportunities to develop more efficacious and better tolerated antiseizure medications. We also review the available data for the two most recently approved antiseizure medications that act, at least in part, through GABAergic mechanisms, namely cenobamate and ganaxolone. Differences in the mode of drug discovery, pharmacological profile, pharmacokinetic properties, drug-drug interaction potential, and clinical efficacy and tolerability of these agents are discussed.

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.

Learnings in developmental and epileptic encephalopathies: what do we know?

INTRODUCTION

Developmental and Epileptic Encephalopathies (DEEs) encompass a group of neurological disorders caused by either abnormal neuronal development and white matter maturation or even by weak synaptic plasticity. Hitherto, patients commonly have epileptic seizures featuring cognitive dysfunction, such as neurosensory disorders, difficulties in learning, behavioral disturbances, or speech delay.

AREAS COVERED

This paper provides a comprehensive review of the current knowledge of DEEs and cognition. Medline/Pubmed database was screened for in-English articles published between 1967-2022 dealing with the topic of DEEs and cognitive development. Two authors independently screened the title and abstract of each record and reviewed the selected articles. Reviews, randomized clinical trials, and case reports were selected.

EXPERT OPINION

Scientific literature has never explicitly dealt with the early neuro-psychomotor rehabilitation and neuropsychological assessment of patients with DEEs. Targeted intervention and environmental stimuli can influence the maturation of neuronal circuits and shape changes in physical and mental development based on neuronal plasticity, particularly if applied in 'critical periods' liable to heightened sensitivity. Thus, 'early neurorehabilitation interventions' are worthy of being more and more applied to clinical practice to improve the quality of life and reduce the psychosocial burden on families and caregivers.

Ganaxolone: A New Treatment for CDKL5 Deficiency Disorder

Safety and Efficacy of Ganaxolone in Patients With CDKL5 Deficiency Disorder: Results From the Double-Blind Phase of a Randomised, Placebo-Controlled, Phase 3 Trial Knight EMP, Amin S, Bahi-Buisson N, Benke TA, Cross JH, Demarest ST, Olson HE, Specchio N, Fleming TR, Aimetti AA, Gasior M, Devinsky O. Lancet Neurol . 2022;21(5):417-427. doi:10.1016/S1474-4422(22)00077-1 Background: CDKL5 deficiency disorder (CDD) is a rare, X-linked, developmental and epileptic encephalopathy characterised by severe global developmental impairment and seizures that can begin in the first few months after birth and are often treatment refractory. Ganaxolone, an investigational neuroactive steroid, reduced seizure frequency in an open-label, phase 2 trial that included patients with CDD. We aimed to further assess the efficacy and safety of ganaxolone in patients with CDD-associated refractory epilepsy. Methods: In the double-blind phase of this randomised, placebo-controlled, phase 3 trial, done at 39 outpatient clinics in eight countries (Australia, France, Israel, Italy, Poland, Russia, the UK, and the USA), patients were eligible if they were aged 2-21 years with a pathogenic or probably pathogenic CDKL5 variant and at least 16 major motor seizures (defined as bilateral tonic, generalised tonic-clonic, bilateral clonic, atonic, or focal to bilateral tonic-clonic) per 28 days in each 4-week period of an 8-week historical period. After a 6-week prospective baseline period, patients were randomly assigned (1:1) via an interactive web response system to receive either enteral adjunctive ganaxolone or matching enteral adjunctive placebo (maximum dose 63 mg/kg per day for patients weighing ≤28 kg or 1800 mg/day for patients weighing >28 kg) for 17 weeks. Patients, caregivers, investigators (including those analysing data), trial staff, and the sponsor (other than the investigational product manager) were masked to treatment allocation. The primary efficacy endpoint was percentage change in median 28-day major motor seizure frequency from the baseline period to the 17-week double-blind phase and was analysed (using a Wilcoxon-rank sum test) in all patients who received at least one dose of trial treatment and for whom baseline data were available. Safety (compared descriptively across groups) was analysed in all patients who received at least one dose of trial treatment. This study is registered with ClinicalTrials.gov , NCT03572933, and the open-label extension phase is ongoing. Findings: Between June 25, 2018, and July 2, 2020, 114 patients were screened for eligibility, of whom 101 (median age 6 years [IQR 3 to 10]) were randomly assigned to receive either ganaxolone (n = 50) or placebo (n = 51). All patients received at least one dose of a study drug, but seizure frequency for one patient in the ganaxolone group was not recorded at baseline and so the primary endpoint was analysed in a population of 100 patients. There was a median percentage change in 28-day major motor seizure frequency of −30.7% (IQR −49.5 to −1.9) in the ganaxolone group and of −6.9% (−24.1 to 39.7) in the placebo group (p = 0.0036). The Hodges-Lehmann estimate of median difference in responses to ganaxolone versus placebo was −27.1% (95% CI −47.9 to −9.6). Treatment-emergent adverse events occurred in 43 (86%) of 50 patients in the ganaxolone group and in 45 (88%) of 51 patients in the placebo group. Somnolence, pyrexia, and upper respiratory tract infections occurred in at least 10% of patients in the ganaxolone group and more frequently than in the placebo group. Serious adverse events occurred in six (12%) patients in the ganaxolone group and in five (10%) patients in the placebo group. Two (4%) patients in the ganaxolone group and four (8%) patients in the placebo group discontinued the trial. There were no deaths in the double-blind phase. Interpretation: Ganaxolone significantly reduced the frequency of CDD-associated seizures compared with placebo and was generally well tolerated. Results from what is, to our knowledge, the first controlled trial in CDD suggest a potential treatment benefit for ganaxolone. Long-term treatment is being assessed in the ongoing open-label extension phase of this trial.