CDKL5 deficiency disorder and other infantile-onset genetic epilepsies

AIM

To differentiate phenotypic features of individuals with CDKL5 deficiency disorder (CDD) from those of individuals with other infantile-onset epilepsies.

METHOD

We performed a retrospective cohort study and ascertained individuals with CDD and comparison individuals with infantile-onset epilepsy who had epilepsy gene panel testing. We reviewed records, updated variant classifications, and compared phenotypic features. Wilcoxon rank-sum tests and χ2 or Fisher's exact tests were performed for between-cohort comparisons.

RESULTS

We identified 137 individuals with CDD (110 females, 80.3%; median age at last follow-up 3 year 11 months) and 313 individuals with infantile-onset epilepsies (156 females, 49.8%; median age at last follow-up 5 years 2 months; 35% with genetic diagnosis). Features reported significantly more frequently in the CDD group than in the comparison cohort included developmental and epileptic encephalopathy (81% vs 66%), treatment-resistant epilepsy (95% vs 71%), sequential seizures (46% vs 6%), epileptic spasms (66% vs 42%, with hypsarrhythmia in 30% vs 48%), regression (52% vs 29%), evolution to Lennox-Gastaut syndrome (23% vs 5%), diffuse hypotonia (72% vs 36%), stereotypies (69% vs 11%), paroxysmal movement disorders (29% vs 17%), cerebral visual impairment (94% vs 28%), and failure to thrive (38% vs 22%).

INTERPRETATION

CDD, compared with other suspected or confirmed genetic epilepsies presenting in the first year of life, is more often characterized by a combination of treatment-resistant epilepsy, developmental and epileptic encephalopathy, sequential seizures, spasms without hypsarrhythmia, diffuse hypotonia, paroxysmal movement disorders, cerebral visual impairment, and failure to thrive. Defining core phenotypic characteristics will improve precision diagnosis and treatment.

Adapting a measure of gross motor skills for individuals with CDKL5 deficiency disorder: A psychometric study

PURPOSE

Validated measures capable of demonstrating meaningful interventional change in the CDKL5 deficiency disorder (CDD) are lacking. The study objective was to modify the Rett Syndrome Gross Motor Scale (RSGMS) and evaluate its psychometric properties for individuals with CDD.

METHODS

Item and scoring categories of the RSGMS were modified. Caregivers registered with the International CDKL5 Clinical Research Network uploaded motor videos filmed at home to a protected server and completed a feedback questionnaire (n = 70). Rasch (n = 137), known groups (n = 109), and intra- and inter-rater reliability analyses (n = 50) were conducted.

RESULTS

The age of individuals with CDD ranged from 1.5 to 34.1 years. The modified scale, Gross Motor-Complex Disability (GM-CD), comprised 17 items. There were no floor or ceiling effects and inter- and intra-rater reliability were good. Rasch analysis demonstrated that the items encompassed a large range of performance difficulty, although there was some item redundancy and some disordered categories. One item, Prone Head Position, was a poor fit. Caregiver-reported acceptability was positive. Scores differed by age and functional abilities.

SUMMARY

GM-CD appears to be a suitable remotely administered measure and psychometrically sound for individuals with CDD. This study provides the foundation to propose the use of GM-CD in CDD clinical trials. Longitudinal evaluation is planned.

Long-term treatment with ganaxolone for seizures associated with cyclin-dependent kinase-like 5 deficiency disorder: Two-year open-label extension follow-up

OBJECTIVE

In the placebo-controlled, double-blind phase of the Marigold study (NCT03572933), ganaxolone significantly reduced major motor seizure frequency (MMSF) in patients with cyclin-dependent kinase-like 5 deficiency disorder (CDD). We report 2-year safety and clinical outcomes data from the open-label extension (OLE) phase of Marigold.

METHODS

Patients with CDD who completed the double-blind phase were eligible to continue in the OLE. Efficacy assessments included MMSF reduction from prerandomization baseline, responder rates, and Clinical Global Impression-Improvement scores, including assessment of seizure intensity and duration (CGI-CSID). Safety assessments included treatment-emergent adverse events (TEAEs) and TEAEs leading to discontinuation.

RESULTS

Of 101 patients who enrolled in Marigold, 88 (87.1%) entered the OLE (median age = 5 years, 79.5% female). Median 28-day MMSF at baseline was 50.6. At 2 years in the OLE (months 22-24), MMSF was reduced by a median of 48.2% (n = 50); when missing data were imputed, median reduction in MMSF was 43.8% using a mixed effects model and 27.4% using a last observation carried forward model. During months 22-24, 23 of 50 (46.0%) patients experienced reductions in MMSF of ≥50%; 12 of 50 (24.0%) patients experienced MMSF reductions of ≥75%. During months 22-24, 40 of 49 (81.6%) patients were rated by caregivers as having improvement in seizure-related outcomes based on CGI-CSID scores. Thirty-seven patients discontinued ganaxolone due to lack of efficacy (n = 13), withdrawal by caregiver (n = 12), adverse event (n = 10), physician decision (n = 1), or death (n = 1; unrelated to study drug). The most common treatment-related TEAEs were somnolence (17.0%), seizure (11.4%), and decreased appetite (5.7%). Patients reported serious TEAEs (n = 28, 31.8%); those reported in ≥3% of patients were seizure (n = 6), pneumonia (n = 5), acute respiratory failure (n = 3), aspiration pneumonia (n = 3), and dehydration (n = 3).

SIGNIFICANCE

Sustained reductions in MMSF at 2 years in the OLE support the efficacy of ganaxolone in seizures associated with CDD. Safety findings in the OLE were consistent with the double-blind phase.

The development, content and response process validation of a caregiver-reported severity measure for CDKL5 deficiency disorder

BACKGROUND

CDKL5 Deficiency Disorder (CDD) is a severe X-linked developmental and epileptic encephalopathy. Existing developmental outcome measures have floor effects and cannot capture incremental changes in symptoms. We modified the caregiver portion of a CDD clinical severity assessment (CCSA) and assessed content and response-process validity.

METHODS

We conducted cognitive interviews with 15 parent caregivers of 1-39-year-old children with CDD. Caregivers discussed their understanding and concerns regarding appropriateness of both questions and answer options. Item wording and questionnaire structure were adjusted iteratively to ensure questions were understood as intended.

RESULTS

The CCSA was refined during three rounds of cognitive interviews into two measures: (1) the CDD Developmental Questionnaire - Caregiver (CDQ-Caregiver) focused on developmental skills, and (2) the CDD Clinical Severity Assessment - Caregiver (CCSA-Caregiver) focused on symptom severity. Branching logic was used to ensure questions were age and skill appropriate. Initial pilot data (n = 11) suggested no floor effects.

CONCLUSIONS

This study modified the caregiver portion of the initial CCSA and provided evidence for its content and response process validity.

Does health literacy mediate the relationship between socioeconomic status and health outcomes?

Background

Health literacy (HL) has been hypothesized as one of the mediators in the pathway through which socioeconomic status (SES) affects health outcomes. This study explores whether HL mediates the relation between SES and a selection of health(-related) outcomes.

Methods

Data from the participants of the Belgian health interview survey 2018 aged 15 years and over were individually linked with data from the Belgian compulsory health insurance (n = 6878). HL was assessed with the HLS-EU-Q6. Mediation analyses were performed using the SES as independent variables, health(-related) outcomes as dependent variables and HL as mediating variable.

Results

People with low SES were less likely to have preventive dental care (PDC), breast cancer screening (BCS), enough physical activity, good nutritional habits, good self-rated health (SRH). In contrast, they were more likely to use antibiotics and antidepressants. A positive correlation was found between HL and PDC, good nutritional habits, physical activity and SRH, but a negative correlation with use of antidepressants. HL partially mediated the association between SES and PDC, use of antidepressants, nutritional habits, physical activity and SRH. In the relationship between these outcomes and education, the mediation effect of HL accounted significantly for 4.4% to 15.4% of the total effect, while it accounted significantly for 4.2% to 12.0% of the total effect in the relationship with income. There was no significant mediating contribution of HL in the pathway by which SES affects influenza vaccination uptake and BCS.

Conclusions

Although the influence of HL in the pathway is limited, the findings suggest that strategies for improving various health(-related) outcomes among low SES groups may benefit from attention to HL. The low percentage mediated for the use of antidepressants might suggest a shared decision between physician and patients.

Key messages

• HL partially mediates the association between SES and PDC, use of antidepressants, nutritional habits, physical activity and SRH. Improving HL might reduce SES disparities in these areas.

• No mediating effects for influenza vaccination uptake and BCS, indicating a possible influence of the universal health coverage in place.

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.

Validating the Communication and Symbolic Behavior Scales-Developmental Profile Infant-Toddler Checklist (CSBS-DP ITC) Beyond Infancy in the CDKL5 Deficiency Disorder

CDKL5 deficiency disorder (CDD) results in early-onset epilepsy and lifelong cognitive and motor impairments. With no validated measure for communication in CDD, this study evaluated the psychometric properties of the Communication and Symbolic Behavior Scales-Developmental Profile Infant Toddler Checklist (CSBS-DP ITC). Caregivers (n = 150; affected individuals aged 1-29 years) completed the CSBS-DP ITC. Distribution of scores indicated a floor effect. There was poor divergent validity for the three-factor model but goodness of fit and convergent validity data were satisfactory for the one-factor model. Individuals with poorer overall functional abilities scored lower on the CSBS-DP ITC. Test-retest reliability was excellent. The floor effect could explain the very high reliability, suggesting problems as a sensitive outcome measure in clinical trials for CDD.

COVID-19 pandemic response in the Meuse-Rhine Euroregion: methods, participation and recommendations of a longitudinal cross-border study

BACKGROUND

Comparative data collection in transborder areas can contribute to informed decision making processes when dealing with borderless health threats such as pandemics, and thus help minimize the negative health effects for its citizens. To examine the pandemic response over time and the impact of infectious disease control in a cross-border setting, a prospective longitudinal study was conducted in the border area between Germany, Belgium and the Netherlands. In the spring of 2021, a random sample of 26,925 adult citizens selected from governmental registries was invited to collect a blood sample at home for SARS-CoV-2 antibody testing and to fill in an online questionnaire on attitudes and behaviour towards infection prevention measures, cross-border mobility, social network and support, COVID-19 self-reported infection(s) and symptoms, vaccination, general self-reported health and socio-demographics. In autumn 2021, participants were invited for a follow-up round. An online tool was developed to coordinate fieldwork procedures, real-time monitoring of participation and consultation of antibody test results. Furthermore, a helpdesk in all three languages for participants' support was set up.

RESULTS

In the first round, 6,006 citizens in the Meuse-Rhine Euroregion participated. 15.3% of the invited citizens on the Belgian side of the border participated. In the Netherlands and Germany this was respectively 27% and 23.7%. In the follow-up round 4,286 (71.4%) citizens participated for the second time. The participation rate was highest in the age group 50-69 years and lowest in > 80 in all sub regions of the Meuse-Rhine Euroregion. More women participated than men. Overall, more blood samples were returned than completed questionnaires. In total, 3,344 citizens in the Meuse-Rhine Euroregion completed all components of participation in both rounds.

CONCLUSIONS

The collection of comparative data can help better assess the pandemic response and the impact of infectious disease control in a cross-border area. Recommendations for a longitudinal cross-border study include a centralized online environment, mapping out potential challenges related to national regulations in the preparation phase and organizing regional coordination centres to create more familiarity and trust towards the involved organisations.

Epilepsy panels in clinical practice: Yield, variants of uncertain significance, and treatment implications

OBJECTIVE

There has been increasing utilization of genetic testing for pediatric epilepsy in recent years. Little systematic data is available examining how practice changes have impacted testing yields, diagnostic pace, incidence of variants of uncertain significance (VUSs), or therapeutic management.

METHODS

A retrospective chart review was performed at Children's Hospital Colorado from February 2016 through February 2020. All patients under 18 years for whom an epilepsy gene panel was sent were included.

RESULTS

A total of 761 epilepsy gene panels were sent over the study period. During the study period, there was a 292% increase in the average number of panels sent per month. The time from seizure onset to panel result decreased over the study period from a median of 2.9 years to 0.7 years. Despite the increase in testing, the percentage of panels yielding a disease-causing result remained stable at 11-13%. A total of 90 disease-causing results were identified, > 75% of which provided guidance in management. Children were more likely to have a disease-causing result if they were < 3 years old at seizure onset (OR 4.4, p < 0.001), had neurodevelopmental concerns (OR 2.2, p = 0.002), or had a developmentally abnormal MRI (OR 3.8, p < 0.001). A total of 1417 VUSs were identified, equating to 15.7 VUSs per disease-causing result. Non-Hispanic white patients had a lower average number of VUSs than patients of all other races/ethnicities (1.7 vs 2.1, p < 0.001).

SIGNIFICANCE

Expansion in the volume of genetic testing corresponded to a decrease in the time from seizure onset to testing result. Diagnostic yield remained stable, resulting in an increase in the absolute number of disease-causing results annually-most of which have implications for management. However, there has also been an increase in total VUSs, which likely resulted in additional clinical time spent on VUS resolution.

Efficacy, safety, and tolerability of soticlestat as adjunctive therapy for the treatment of seizures in patients with Dup15q syndrome or CDKL5 deficiency disorder in an open-label signal-finding phase II study (ARCADE)

OBJECTIVE

Chromosome 15q duplication (Dup15q) syndrome and cyclin‑dependent kinase-like 5 deficiency disorder (CDD) are rare neurodevelopmental disorders associated with epileptic encephalopathies, with a lack of specifically approved treatment options. ARCADE assessed the efficacy and safety of adjunctive soticlestat (TAK-935) for the treatment of seizures in patients with Dup15q syndrome or CDD (NCT03694275).

METHODS

ARCADE was a phase II, open-label, pilot study of soticlestat (≤300 mg/day twice daily, weight-adjusted) in pediatric and adult patients 2-55 years of age with Dup15q syndrome or CDD who experienced ≥3 motor seizures per month in the 3 months before screening and at baseline. The 20-week treatment period consisted of a dose-optimization period and a 12-week maintenance period. Efficacy endpoints included the change from baseline in motor seizure frequency during the maintenance period and the proportion of treatment responders. Safety endpoints included the incidence of treatment-emergent adverse effects (TEAEs).

RESULTS

The modified-intent-to-treat population included 20 participants who received ≥1 dose of soticlestat and had ≥1 efficacy assessment (Dup15q syndrome, n = 8; CDD, n = 12). Soticlestat administration during the maintenance period was associated with a median change from baseline in motor seizure frequency of +11.7% in the Dup15q syndrome group and -23.6% in the CDD group. Reductions in all seizure frequency of -23.4% and -30.5% were also observed during the maintenance period in the Dup15q syndrome group and the CDD group, respectively. Most TEAEs were of mild or moderate severity. Serious TEAEs were reported by three patients (15.0%); none were considered drug related. The most common TEAEs were constipation, rash, and seizure. No deaths were reported.

CONCLUSIONS

Adjunctive soticlestat treatment was associated with a decrease in motor seizure frequency from baseline in patients with CDD and a decrease in all seizure frequency in both patient groups. Soticlestat treatment was associated with an increase in motor seizure frequency in patients with Dup15q syndrome.

Psychometric properties of QI-Disability in CDKL5 Deficiency Disorder: Establishing readiness for clinical trials

CDKL5 Deficiency Disorder (CDD) is a rare genetic disorder with symptoms of epilepsy, developmental impairments, and other comorbidities. Currently, there are no outcome measures for CDD with comprehensive evidence of validation. This study aimed to evaluate the psychometric properties of the Quality of Life Inventory-Disability (QI-Disability) in CDD. Quality of Life Inventory-Disability was administered to 152 parent caregivers registered with the International CDKL5 Disorder Database (ICDD). Confirmatory factor analysis was conducted and the goodness of fit of the factor structure was assessed. Fixed-effects linear regression models examined the responsiveness of QI-Disability to reported changes in child health. A subset of parent caregivers (n = 56) completed QI-Disability, as well as additional health-related questions, on two occasions separated by four weeks to evaluate test-retest reliability. Test-retest reliability was assessed using intra-class correlations (ICCs) calculated from QI-Disability scores. Based upon adjustments for changes in child health, ICCs were recalculated to estimate responsiveness to change. Confirmatory factor analysis, internal consistency, and divergent validity were mostly satisfactory, except divergent validity was not satisfactory for the Social Interactions and Independence domains. The Physical Health, Social Interactions, Leisure, and Total scores responded to changes in the child's Physical health, and the Negative Emotions and Leisure domains responded to changes in the child's behavior. Unadjusted and adjusted ICC values were above 0.8 for the Positive Emotions, Negative Emotions, Social Interactions, Leisure, Independence domains and Total score, and above 0.6 for the Physical Health domain. Findings suggest that QI-Disability is suitable to assess the quality of life of children and adults with CDD and could be of value for upcoming clinical trials.

Patterns of developmental regression and associated clinical characteristics in SLC6A1-related disorder

Introduction

SLC6A1-related disorder is a genetic neurodevelopmental disorder that is caused by loss of function variants in the SLC6A1 gene. Solute Carrier Family 6 Member 1 (SLC6A1) gene encodes for gamma-aminobutyric acid (GABA) transporter type 1 (GAT1), which is responsible for reuptake of GABA from the synaptic cleft. Tight regulation of GABA levels plays an important role in brain development by balancing inhibitory and excitatory neuronal signaling. Consequently, individuals with SLC6A1-related disorder can have manifestations such as developmental delay, epilepsy, autism spectrum disorder, and a subset have developmental regression.

Methods

In this study, we identified patterns of developmental regression among a cohort of 24 patients with SLC6A1-related disorder and assessed for clinical characteristics associated with regression. We reviewed medical records of patients with SLC6A1-related disorder and divided subjects into two groups: 1) regression group and 2) control group. We described the patterns of developmental regression including whether there was a trigger prior to the regression, multiple episodes of regression, and whether or not skills were recovered. We assessed the relationship of clinical characteristics among the regression and control groups including demographic factors, seizures, developmental milestone acquisition, gastrointestinal problems, sleep problems, autism spectrum disorder, and behavioral problems.

Results

Individuals with developmental regression had a loss of skills that were previously mastered in developmental domains including speech and language, motor, social, and adaptive skills. The mean age at regression was 2.7 years and most subjects had regression of language or motor skills triggered by seizures, infection, or spontaneously. Although there was no significant difference in clinical characteristics between the two groups, there was a higher prevalence of autism and severe language impairment in the regression group.

Discussion

Future studies of a larger cohort of patients are required to make definitive conclusions. Developmental regression is often a sign of severe neurodevelopmental disability in genetic syndromes, but it is poorly understood in SLC6A1-related disorder. Understanding the patterns of developmental regression and the associated clinical characteristics in this rare disorder will be important to medical management, prognostication, and could impact the design of future clinical trials.

Quality of life beyond diagnosis in intellectual disability - Latent profiling

OBJECTIVE

To compare quality of life (QOL) across diagnoses associated with intellectual disability, construct QOL profiles and evaluate membership by diagnostic group, function and comorbidities.

METHOD

Primary caregivers of 526 children with intellectual disability (age 5-18 years) and a diagnosis of cerebral palsy, autism spectrum disorder, Down syndrome, CDKL5 deficiency disorder or Rett syndrome completed the Quality of Life Inventory-Disability (QI-Disability) questionnaire. Latent profile analysis of the QI-Disability domain scores was conducted.

RESULTS

The mean (SD) total QOL score was 67.8 (13.4), ranging from 60.3 (14.6) for CDD to 77.5 (11.7) for Down syndrome. Three classes describing domain scores were identified: Class 1 was characterised by higher domain scores overall but poorer negative emotions scores; Class 2 by average to high scores for most domains but low independence scores; and Class 3 was characterised by low positive emotions, social interaction, and leisure and the outdoors scores, and extremely low independence scores. The majority of individuals with autism spectrum disorder and Down syndrome belonged to Class 1 and the majority with CDKL5 deficiency disorder belonged to Class 3. Those with better functional abilities (verbal communication and independent walking were predominately members of Class 1 and those with frequent seizures were more often members of Class 2 and 3.

CONCLUSION

The profiles illustrated variation in QOL across a diverse group of children. QOL evaluations illustrate areas where interventions could improve QOL and provide advice to families as to where efforts may be best directed.

Precision medicine for genetic epilepsy on the horizon: Recent advances, present challenges, and suggestions for continued progress

The genetic basis of many epilepsies is increasingly understood, giving rise to the possibility of precision treatments tailored to specific genetic etiologies. Despite this, current medical therapy for most epilepsies remains imprecise, aimed primarily at empirical seizure reduction rather than targeting specific disease processes. Intellectual and technological leaps in diagnosis over the past 10 years have not yet translated to routine changes in clinical practice. However, the epilepsy community is poised to make impressive gains in precision therapy, with continued innovation in gene discovery, diagnostic ability, and bioinformatics; increased access to genetic testing and counseling; fuller understanding of natural histories; agility and rigor in preclinical research, including strategic use of emerging model systems; and engagement of an evolving group of stakeholders (including patient advocates, governmental resources, and clinicians and scientists in academia and industry). In each of these areas, we highlight notable examples of recent progress, new or persistent challenges, and future directions. The future of precision medicine for genetic epilepsy looks bright if key opportunities on the horizon can be pursued with strategic and coordinated effort.

Negative impact of insomnia and daytime sleepiness on quality of life in individuals with the cyclin-dependent kinase-like 5 deficiency disorder

Cyclin-dependent kinase-like 5 (CDKL5) gene pathogenic variants result in CDKL5 deficiency disorder (CDD). Early onset intractable epilepsy and severe developmental delays are prominent symptoms of CDD. Comorbid sleep disturbances are a major concerning symptom for families. We aimed to explore the relationship between insomnia, daytime sleepiness, sleep medications and quality of life in children with CDD. Caregivers of 129 children with CDD in the International CDKL5 Disorder Database completed the Quality-of-Life Inventory-Disability (QI-Disability) questionnaire and "Disorders of Maintaining Sleep" (DIMS) and the "Disorders of Excessive Somnolence" (DOES) items of the Sleep Disturbance Scale for Children. Adjusting for covariates, a unit increase in DOES score was associated with reduced quality of life total (coefficient -3.06, 95% confidence interval [CI] 1.35-7.80), physical health (coefficient -7.20, 95% CI -10.64, -3.76) and negative emotions (coefficient -3.90, 95% CI -7.38, -0.42) scores. Adjusting for covariates, a unit increase in DIMS score was associated with reduced negative emotions (coefficient -6.02, 95% CI -10.18, -2.86). Use of sleep medications had small influences on the effect sizes. This study highlights the importance of sleep problems as a determinant of quality of life in children with CDD, consistent with effects observed for other groups of children with intellectual disability. Excessive daytime sleepiness was particularly associated with detrimental effects on quality of life. Further research in optimal behavioural and pharmaceutical management of sleep problems for this population is required.

Devising a Missing Data Rule for a Quality of Life Questionnaire-A Simulation Study

OBJECTIVE

The aim of this study was to devise an evidence-based missing data rule for the Quality of Life Inventory-Disability (QI-Disability) questionnaire specifying how many missing items are permissible for domain and total scores to be calculated using simple imputation. We sought a straightforward rule that can be used in both research and clinical monitoring settings.

METHOD

A simulation study was conducted involving random selection of missing items from a complete data set of questionnaire responses. This comprised 520 children with intellectual disability from 5 diagnostic groups. We applied a simple imputation scheme, and the simulated distribution of errors induced by imputation was compared with the previously estimated standard error of measurement (SEM) for each domain.

RESULTS

Using a stringent criterion, which requires that the 95th percentile of absolute error be less than the SEM, 1 missing item should be permitted for 2 of the 6 QI-Disability subdomain scores to be calculated and 1 missing item per domain for the total score to be calculated. Other, less stringent criteria would allow up to 2 missing items per domain.

CONCLUSION

Empirical evidence about the impact of imputing missing questionnaire responses can be gathered using simulation methods applied to a complete data set. We recommend that such evidence be used in devising a rule that specifies how many items can be imputed for a valid score to be calculated.

Assessing the landscape of STXBP1-related disorders in 534 individuals

Disease-causing variants in STXBP1 are among the most common genetic causes of neurodevelopmental disorders. However, the phenotypic spectrum in STXBP1-related disorders is wide and clear correlations between variant type and clinical features have not been observed so far. Here, we harmonized clinical data across 534 individuals with STXBP1-related disorders and analysed 19 973 derived phenotypic terms, including phenotypes of 253 individuals previously unreported in the scientific literature. The overall phenotypic landscape in STXBP1-related disorders is characterized by neurodevelopmental abnormalities in 95% and seizures in 89% of individuals, including focal-onset seizures as the most common seizure type (47%). More than 88% of individuals with STXBP1-related disorders have seizure onset in the first year of life, including neonatal seizure onset in 47%. Individuals with protein-truncating variants and deletions in STXBP1 (n = 261) were almost twice as likely to present with West syndrome and were more phenotypically similar than expected by chance. Five genetic hotspots with recurrent variants were identified in more than 10 individuals, including p.Arg406Cys/His (n = 40), p.Arg292Cys/His/Leu/Pro (n = 30), p.Arg551Cys/Gly/His/Leu (n = 24), p.Pro139Leu (n = 12), and p.Arg190Trp (n = 11). None of the recurrent variants were significantly associated with distinct electroclinical syndromes, single phenotypic features, or showed overall clinical similarity, indicating that the baseline variability in STXBP1-related disorders is too high for discrete phenotypic subgroups to emerge. We then reconstructed the seizure history in 62 individuals with STXBP1-related disorders in detail, retrospectively assigning seizure type and seizure frequency monthly across 4433 time intervals, and retrieved 251 anti-seizure medication prescriptions from the electronic medical records. We demonstrate a dynamic pattern of seizure control and complex interplay with response to specific medications particularly in the first year of life when seizures in STXBP1-related disorders are the most prominent. Adrenocorticotropic hormone and phenobarbital were more likely to initially reduce seizure frequency in infantile spasms and focal seizures compared to other treatment options, while the ketogenic diet was most effective in maintaining seizure freedom. In summary, we demonstrate how the multidimensional spectrum of phenotypic features in STXBP1-related disorders can be assessed using a computational phenotype framework to facilitate the development of future precision-medicine approaches.

CDKL5 deficiency disorder: clinical features, diagnosis, and management

CDKL5 deficiency disorder (CDD) was first identified as a cause of human disease in 2004. Although initially considered a variant of Rett syndrome, CDD is now recognised as an independent disorder and classified as a developmental epileptic encephalopathy. It is characterised by early-onset (generally within the first 2 months of life) seizures that are usually refractory to polypharmacy. Development is severely impaired in patients with CDD, with only a quarter of girls and a smaller proportion of boys achieving independent walking; however, there is clinical variability, which is probably genetically determined. Gastrointestinal, sleep, and musculoskeletal problems are common in CDD, as in other developmental epileptic encephalopathies, but the prevalence of cerebral visual impairment appears higher in CDD. Clinicians diagnosing infants with CDD need to be familiar with the complexities of this disorder to provide appropriate counselling to the patients' families. Despite some benefit from ketogenic diets and vagal nerve stimulation, there has been little evidence that conventional antiseizure medications or their combinations are helpful in CDD, but further treatment trials are finally underway.

Whole-exome sequencing and adrenocorticotropic hormone therapy in individuals with infantile spasms

AIM

To identify additional genes associated with infantile spasms using a cohort with defined infantile spasms.

METHOD

Whole-exome sequencing (WES) was performed on 21 consented individuals with infantile spasms and their unaffected parents (a trio-based study). Clinical history and imaging were reviewed. Potentially deleterious exonic variants were identified and segregated. To refine potential candidates, variants were further prioritized on the basis of evidence for relevance to disease phenotype or known associations with infantile spasms, epilepsy, or neurological disease.

RESULTS

Likely pathogenic de novo variants were identified in NR2F1, GNB1, NEUROD2, GABRA2, and NDUFAF5. Suggestive dominant and recessive candidate variants were identified in PEMT, DYNC1I1, ASXL1, RALGAPB, and STRADA; further confirmation is required to support their relevance to disease etiology.

INTERPRETATION

This study supports the utility of WES in uncovering the genetic etiology in undiagnosed individuals with infantile spasms with an overall yield of five out of 21. High-priority candidates were identified in an additional five individuals. WES provides additional support for previously described disease-associated genes and expands their already broad mutational and phenotypic spectrum.

The Lived Experience of Parents' Receiving the Diagnosis of CDKL5 Deficiency Disorder for Their Child

CDKL5 deficiency disorder (CDD), a severe developmental and epileptic encephalopathy, is being diagnosed earlier with improved access to genetic testing, but this may also have unanticipated impacts on parents' experience receiving the diagnosis. This study explores the lived experience of parents receiving a diagnosis of CDD for their child using mixed methods. Thirty-seven semistructured interviews were conducted with parents of children with a diagnosis of CDD, which were coded and analyzed to identify themes. Grief was a nearly universal theme expressed among participants. Parents of younger children discussed grief in the context of receiving the diagnosis, whereas parents of older children indicated they were at different stages along the grieving journey when they received the diagnosis. Parents with less understanding of their child's prognosis (poorer prognostic awareness) connected their grief to receiving the diagnosis as this brought a clear understanding of the prognosis. Several themes suggested what providers did well to improve the diagnostic experience for parents, much of which aligns with existing literature around how to provide serious news. Additionally, parents identified long-term benefits of having a diagnosis for their child's medical problems. Although interview data were concordant with a survey of parents' diagnostic experience from a large international cohort, most participants in this study were relatively affluent, white mothers and further research is needed to better understand if other groups of parents have a different diagnostic experience. This study gives context of parental experience that providers should be aware of when conveying new genetic diagnoses to families.

Initial Validation and Reliability of the CDKL5 Deficiency Disorder Hand Function Scale (CDD-Hand)

Pathogenic variants in the CDKL5 gene result in CDKL5 deficiency disorder (CDD), which is characterized by early-onset epilepsy, severe developmental delay, and often, cortical visual impairment. Validated clinical outcome measures are needed for future clinical trials to be successful. This study aimed to adapt the Rett Syndrome Hand Function Scale for CDKL5 deficiency disorder and evaluate its feasibility, acceptability, content validity, and reliability. Consultation with a cortical visual impairment experienced specialist and the Consumer Reference Group informed modifications to the instructions of the Rett Syndrome Hand Function Scale for children with CDKL5 deficiency disorder (CDD-Hand). Eighty-six families registered with the International CDKL5 Disorder Database provided video clips of their child's hand function and provided feedback about the measure. Video data were coded by 2 researchers to evaluate intra- and interrater reliability. This study provides initial evidence of validation and reliability. The scale appears to be suitable for a range of ages and functional abilities for CDKL5 deficiency disorder.

De novo DHDDS variants cause a neurodevelopmental and neurodegenerative disorder with myoclonus

Subcellular membrane systems are highly enriched in dolichol, whose role in organelle homeostasis and endosomal-lysosomal pathway remains largely unclear besides being involved in protein glycosylation. DHDDS encodes for the catalytic subunit (DHDDS) of the enzyme cis-prenyltransferase (cis-PTase), involved in dolichol biosynthesis and dolichol-dependent protein glycosylation in the endoplasmic reticulum. An autosomal recessive form of retinitis pigmentosa (retinitis pigmentosa 59) has been associated with a recurrent DHDDS variant. Moreover, two recurring de novo substitutions were detected in a few cases presenting with neurodevelopmental disorder, epilepsy and movement disorder. We evaluated a large cohort of patients (n = 25) with de novo pathogenic variants in DHDDS and provided the first systematic description of the clinical features and long-term outcome of this new neurodevelopmental and neurodegenerative disorder. The functional impact of the identified variants was explored by yeast complementation system and enzymatic assay. Patients presented during infancy or childhood with a variable association of neurodevelopmental disorder, generalized epilepsy, action myoclonus/cortical tremor and ataxia. Later in the disease course, they experienced a slow neurological decline with the emergence of hyperkinetic and/or hypokinetic movement disorder, cognitive deterioration and psychiatric disturbances. Storage of lipidic material and altered lysosomes were detected in myelinated fibres and fibroblasts, suggesting a dysfunction of the lysosomal enzymatic scavenger machinery. Serum glycoprotein hypoglycosylation was not detected and, in contrast to retinitis pigmentosa and other congenital disorders of glycosylation involving dolichol metabolism, the urinary dolichol D18/D19 ratio was normal. Mapping the disease-causing variants into the protein structure revealed that most of them clustered around the active site of the DHDDS subunit. Functional studies using yeast complementation assay and in vitro activity measurements confirmed that these changes affected the catalytic activity of the cis-PTase and showed growth defect in yeast complementation system as compared with the wild-type enzyme and retinitis pigmentosa-associated protein. In conclusion, we characterized a distinctive neurodegenerative disorder due to de novo DHDDS variants, which clinically belongs to the spectrum of genetic progressive encephalopathies with myoclonus. Clinical and biochemical data from this cohort depicted a condition at the intersection of congenital disorders of glycosylation and inherited storage diseases with several features akin to of progressive myoclonus epilepsy such as neuronal ceroid lipofuscinosis and other lysosomal disorders.

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

CDKL5 Deficiency Disorder (CDD) is a rare, X-linked dominant condition that causes a developmental and epileptic encephalopathy (DEE). The incidence is between ~ 1:40,000 and 1:60,000 live births. Pathogenic variants in CDKL5 lead to seizures from infancy and severe neurodevelopmental delay. During infancy and childhood, individuals with CDD suffer impairments affecting cognitive, motor, visual, sleep, gastrointestinal and other functions. Here we present the recommendations of international healthcare professionals, experienced in CDD management, to address the multisystem and holistic needs of these individuals. Using a Delphi method, an anonymous survey was administered electronically to an international and multidisciplinary panel of expert clinicians and researchers. To provide summary recommendations, consensus was set, a priori, as >70% agreement for responses. In the absence of large, population-based studies to provide definitive evidence for treatment, we propose recommendations for clinical management, influenced by this proposed threshold for consensus. We believe these recommendations will help standardize, guide and improve the medical care received by individuals with CDD.

Cerebral Visual Impairment in CDKL5 Deficiency Disorder Correlates With Developmental Achievement

Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder is a rare neurodevelopmental disorder characterized by infantile-onset refractory epilepsy, profound developmental delays, and cerebral visual impairment. Although there is evidence that the presence of cerebral visual impairment in CDKL5 deficiency disorder is common, the potential impact of cerebral visual impairment severity on developmental attainment has not been explored directly. Focusing on a cohort of 46 children with CDKL5 deficiency disorder, examination features indicative of cerebral visual impairment were quantified and compared to developmental achievement. The derived cerebral visual impairment severity score was inversely correlated with developmental attainment, bolstering the supposition that cerebral visual impairment severity may provide a useful early biomarker of disease severity and prognosis. This study demonstrates the utility of a cerebral visual impairment score to better capture the range of cerebral visual impairment severity in the CDKL5 deficiency disorder population and further elucidates the interaction between cerebral visual impairment and developmental outcomes.

Content Validation of Clinician-Reported Items for a Severity Measure for CDKL5 Deficiency Disorder

CDKL5 deficiency disorder (CDD) results in early-onset seizures and severe developmental impairments. A CDD clinical severity assessment (CCSA) was previously developed with clinician and parent-report items to capture information on a range of domains. Consistent with US Food and Drug Administration (FDA) guidelines, content validation is the first step in evaluating the psychometric properties of an outcome measure. The aim of this study was to validate the content of the clinician-reported items in the CCSA (CCSA-Clinician). Eight neurologists leading the USA CDD Center of Excellence clinics were interviewed using the "think aloud" technique to critique 26 clinician-reported items. Common themes were aggregated, and a literature search of related assessments informed item modifications. The clinicians then participated in 2 consensus meetings to review themes and finalize the items. A consensus was achieved for the content of the CCSA-Clinician. Eight of the original items were omitted, 11 items were added, and the remaining 18 items were revised. The final 29 items were classified into 2 domains: functioning and neurologic impairments. This study enabled refinement of the CCSA-Clinician and provided evidence for its content validity. This preliminary validation is essential before field testing and further validation, in order to advance the instrument toward clinical trial readiness.

Evolution of Infantile Spasms to Lennox-Gastaut Syndrome: What Is There to Know?

OBJECTIVE

Children with infantile spasms may develop Lennox-Gastaut syndrome. The diagnostic criteria for Lennox-Gastaut syndrome are vague, and many experts use varying combinations of the following criteria for diagnosis: paroxysmal fast activity on electroencephalography (EEG), slow spike and wave on EEG, developmental delay, multiple seizure types, and nocturnal tonic seizures. Our objective was to determine the prevalence of Lennox-Gastaut syndrome in a high-risk cohort of children with a history of infantile spasms and the characteristics of infantile spasms that were associated with the diagnosis of Lennox-Gastaut syndrome.

METHODS

Children with infantile spasms who were diagnosed and treated at Children's Hospital Colorado between 2012 and 2018 were included. Lennox-Gastaut syndrome was defined as having 3 of 5 of the following characteristics: paroxysmal fast activity, slow spike and wave, current developmental delay, multiple seizure types, or tonic seizures. Descriptive statistics were performed using median and interquartile range. Univariable analysis was performed with Pearson chi-square, Fisher exact, or the Kruskal-Wallis test.

RESULTS

Ninety-seven children met inclusion criteria, and 36% (35/97) met criteria for Lennox-Gastaut syndrome. Developmental delay and history of seizures prior to the onset of infantile spasms were identified as risk factors for the development of Lennox-Gastaut syndrome (P = .003) as was poor response to first treatment for spasms (P = .004). Children with an unknown etiology of infantile spasms were less likely to develop Lennox-Gastaut syndrome (P = .019). Eighty percent (28/35) of the children who met Lennox-Gastaut syndrome criteria lacked a documented diagnosis.

CONCLUSIONS

Thirty-six percent of children with infantile spasms met criteria for Lennox-Gastaut syndrome. Risk factors for development of Lennox-Gastaut syndrome were developmental delay and seizures prior to the onset of infantile spasms and poor response to first treatment for infantile spasms. Children with an unknown etiology of infantile spasms were less likely to develop Lennox-Gastaut syndrome. Eighty percent of the children who met our criteria were not given a documented diagnosis of Lennox-Gastaut syndrome, which highlights the fact that many children may not be receiving a diagnosis of Lennox-Gastaut syndrome. We recommend establishing clear guidelines for the diagnosis of Lennox-Gastaut syndrome to ensure that the diagnosis is being made accurately.

Haploinsufficiency, Dominant Negative, and Gain-of-Function Mechanisms in Epilepsy: Matching Therapeutic Approach to the Pathophysiology

This review summarizes the pathogenic mechanisms that underpin the monogenic epilepsies and discusses the potential of novel precision therapeutics to treat these disorders. Pathogenic mechanisms of epilepsy include recessive (null alleles), haploinsufficiency, imprinting, gain-of-function, and dominant negative effects. Understanding which pathogenic mechanism(s) that underlie each genetic epilepsy is pivotal to design precision therapies that are most likely to be beneficial for the patient. Novel therapeutics discussed include gene therapy, gene editing, antisense oligonucleotides, and protein replacement. Discussions are illustrated and reinforced with examples from the literature.

Clinical Trial Design for Disease-Modifying Therapies for Genetic Epilepsies

Although trials with anti-seizure medications (ASMs) have not shown clear anti-epileptogenic or disease-modifying activity in humans to date, rapid advancements in genomic technology and emerging gene-mediated and gene replacement options offer hope for the successful development of disease-modifying therapies (DMTs) for genetic epilepsies. In fact, more than 26 potential DMTs are in various stages of preclinical and/or clinical development for genetic syndromes associated with epilepsy. The scope of disease-modification includes but is not limited to effects on the underlying pathophysiology, the condition's natural history, epilepsy severity, developmental achievement, function, behavior, sleep, and quality of life. While conventional regulatory clinical trials for epilepsy therapeutics have historically focused on seizure reduction, similarly designed trials may prove ill-equipped to identify these broader disease-modifying benefits. As we look forward to this pipeline of DMTs, focused consideration should be given to the challenges they pose to conventional clinical trial designs for epilepsy therapeutics. Just as DMTs promise to fundamentally alter how we approach the care of patients with genetic epilepsy syndromes, DMTs likewise challenge how we traditionally construct and measure the success of clinical trials. In the following, we briefly review the historical and preclinical frameworks for DMT development for genetic epilepsies and explore the many novel challenges posed for such trials, including the choice of suitable outcome measures, trial structure, timing and duration of treatment, feasible follow-up period, varying safety profile, and ethical concerns.

Results of an international Delphi consensus in epilepsy with myoclonic atonic seizures/ Doose syndrome

OBJECTIVE

To establish a standard framework for early phenotypic diagnosis, investigations, expected findings from investigations, evolution, effective therapies and prognosis in the syndrome of Epilepsy with myoclonic atonic seizures (EMAS) / Doose syndrome.

METHODS

A core study group (CSG) interested in EMAS was convened. CSG then identified and nominated 15 experts in the field of EMAS. This expert panel (EP) from English speaking nations was invited to participate in anonymous questionnaires. A literature review was provided to them (supplement 1). Three rounds of questionnaires were sent to identify areas of consensus, strength of consensus and areas of contention.

RESULTS

Strong consensus was obtained regarding the clinical phenotype of EMAS: myoclonic atonic seizure was identified among others as a mandatory seizure type with typical onset of afebrile seizures between one and six years. A new term "stormy phase" (SP) was designated to delineate a characteristic phenotypic evolution in EMAS patients associated with seizure worsening. Strong consensus regarding the existence and time of onset of the SP, mandatory investigations to be performed early and later in the clinical course of EMAS, first and second tier treatment and prognostic factors for poor outcome were identified. Areas of lack of consensus included some seizure types that are necessary to diagnose EMAS, interictal EEG findings that prognosticate the course of EMAS, overall duration of SP, time to complete remission, and best approach to treat drug resistant EMAS.

SIGNIFICANCE

Expert consensus on core diagnostic criteria of EMAS necessary for natural history studies, phenotype-genotype correlations, and clinical trials including comparative studies was demonstrated. Areas of disagreements (especially prognostic features; treatment options) need further research.

Exploring quality of life in individuals with a severe developmental and epileptic encephalopathy, CDKL5 Deficiency Disorder

BACKGROUND

CDKL5 Deficiency Disorder (CDD) is a rare genetic disorder caused by a mutation in the cyclin-dependent kinase-like 5 (CDKL5) gene. It is now considered to be a developmental and epileptic encephalopathy because of the early onset of seizures in association with severe global delay. Other features include cortical visual impairment, sleep and gastro-intestinal problems. Progress in clinical understanding, especially regarding the spectrum of functional ability, seizure patterns, and other comorbidities was initially slow but accelerated in 2012 with the establishment of the International CDKL5 Database (ICDD). Our aim was to use this data source to investigate quality of life (QOL) and associated factors in this disorder.

METHOD

A follow-up questionnaire was administered in 2018 to parents of children registered with the ICDD who had a pathogenic CDKL5 variant. QOL was assessed using QI Disability, an instrument, specifically developed to measure total and specific domains of QOL (physical health, positive emotions, negative emotions, social interaction, leisure and the outdoors (leisure) and independence) in children with intellectual disability. Associations with functional abilities, physical health, mental health and family factors were investigated, initially using univariate analyses followed by multivariate analyses for each of these groups with a final composite model which included the important variables identified from previous models.

RESULTS

Questionnaires were returned by 129/160 families with a child aged >3 years. Functional impairment, including lack of ability to sit, use hands and communicate had the greatest adverse impact on QOL. There were also some relationships with major genotype groupings. Individuals using three or more anti-epileptic medications had poorer QOL than those on one or no medication, particularly in the physical health domain. There was also variation by geographical region with those living in North America typically having the best QOL and those living in middle or lower income countries poorer QOL.

CONCLUSION

Although lower functional abilities were associated with poorer quality of life further research is needed to understand how environmental supports might mitigate this deficit. Comprehensive care and support for both the child and family have important roles to play in helping families to thrive despite the severity of CDD.

Current knowledge of SLC6A1-related neurodevelopmental disorders

Advances in gene discovery have identified genetic variants in the solute carrier family 6 member 1 gene as a monogenic cause of neurodevelopmental disorders, including epilepsy with myoclonic atonic seizures, autism spectrum disorder and intellectual disability. The solute carrier family 6 member 1 gene encodes for the GABA transporter protein type 1, which is responsible for the reuptake of the neurotransmitter GABA, the primary inhibitory neurotransmitter in the central nervous system, from the extracellular space. GABAergic inhibition is essential to counterbalance neuronal excitation, and when significantly disrupted, it negatively impacts brain development leading to developmental differences and seizures. Aggregation of patient variants and observed clinical manifestations expand understanding of the genotypic and phenotypic spectrum of this disorder. Here, we assess genetic and phenotypic features in 116 individuals with solute carrier family 6 member 1 variants, the vast majority of which are likely to lead to GABA transporter protein type 1 loss-of-function. The knowledge acquired will guide therapeutic decisions and the development of targeted therapies that selectively enhance transporter function and may improve symptoms. We analysed the longitudinal and cell type-specific expression of solute carrier family 6 member 1 in humans and localization of patient and control missense variants in a novel GABA transporter protein type 1 protein structure model. In this update, we discuss the progress made in understanding and treating solute carrier family 6 member 1-related disorders thus far, through the concerted efforts of clinicians, scientists and family support groups.

Brief assessment of (in)direct questions on domestic/partner violence in the Belgian HIS 2013-2018

Background

Domestic and partner violence have considerable physical and mental consequences for the victims. The Belgian Health Interview Survey (HIS) 2013 previously evaluated a combination of two (indirect) related questions as an appropriate tool to assess domestic and partner violence in the general population. A more direct approach in the HIS 2018 will be compared with the HIS 2013 deduction method.

Methods

The HIS is a cross-sectional survey in a representative population sample. The more sensitive subjects like domestic and partner violence are part of the self-administered questionnaire. In 2013 the indicator related to domestic violence was derived from the question whether the perpetrators was a member of the household; for the indicator on partner violence also the household composition was taken into account. For the HIS 2018, the question has been adapted. It was specifically asked who the perpetrator was (i.e. unknown, colleague, acquaintance, friend, (ex-)partner, parents, children) from where easily these two indicators could be defined. Proportions are compared.

Results

In 2018, 1.0% of the population aged 15+ indicated being victim of domestic violence in the past 12 months, which is in line with the proportion found in 2013 (1.1%). However, for partner violence there is a difference in the proportions. In 2018, 0.6% of the population 18-74 years indicated being victim of partner violence in the past 12 months, which is only half of the proportion found in 2013 (1.3%).

Conclusions

For assessing domestic violence, defining perpetrators as members of the household or detailed questioning about the relationship towards the perpetrator produce similar results. For distinguishing partner violence, the estimations benefit from directly defining the relationship towards the perpetrator.

Key messages

Even when investigating sensitive topics, straightforward questions produce more accurate results. The problem of domestic violence and partner violence remains underreported and so it needs to be explored more.

Response patterns in the Belgian health interview survey: web versus face-to-face mode

Background

Potential is seen in web data collection for population health surveys due to a combination of its cost-effectiveness and ease of implementation and the increased internet penetration rates. Nonetheless, web modes may lead to lower and more selective unit response rates than traditional modes such as face-to-face (F2F) interviewing and hence may increase bias in the measured indicators. This research assesses the response patterns of a web versus F2F study.

Methods

A Belgian health interview survey by web (BHISWEB; net sample=1010) was organized parallel to the traditional F2F BHIS 2018 (BHIS2018; net sample=11611; subsample used in this study=2748). Socio-demographic data on invited individuals were obtained from the national register and census linkages. To address the high item-missingness on education level deriving from the census, multiple imputation (m = 20) was applied. Unit response rates considering the different sampling probabilities of both surveys were calculated. Logistic regression analyses examined the impact of mode (web vs. F2F) and interactions between mode and socio-demographic characteristics on unit response.

Results

The unit response rate was significantly lower in the BHISWEB (18.0% (95% CI: 17.0-19.1)) than in the BHIS2018 (43.1% (95% CI: 41.5-44.7)). A lower web versus F2F response rate was found among all socio-demographic groups, however, this lower web response was less pronounced among youngsters, people cohabiting with household members, higher educated people and native Belgians.

Conclusions

The F2F unit response rate was generally higher, yet for certain groups the difference between web versus F2F was smaller. It is therefore worthwhile to experiment with adaptive mixed-mode designs to optimize resources without increasing selection bias; e.g. only inviting socio-demographic groups more eager to participate online for web surveys (e.g. youngsters) while remaining to focus on increasing the F2F response rates for other groups.

Key messages

The advantages of web versus F2F interviewing come against its considerable lower unit response rate. Differences in unit non-response between web and F2F vary between socio-demographic groups.

Social inequalities in overweight and obesity in 26 European countries

Background

Previous studies have shown inequalities in overweight and obesity in disfavor of the socially disadvantaged groups. This study examines the extent of these inequalities in 26 European countries.

Methods

Data from the 2017 EU Statistics on Income and living Conditions (EU-SILC) were used (18 years and older, n = 482,595). A body mass index of 25.0 to 29.9 kg/m2 was classified as overweight and 30.0 and more as obese. Educational level (EL) was used as socioeconomic indicator. Generalized linear models were fitted to compute low-versus high absolute (RD) and relative (RR) inequality. Absolute inequality amplitude (RDA) was calculated as RD/Prevalence.

Results

Among men, average EU inequalities for overweight were slightly in disfavor of the low educated (RR = 1.05, RDA=5%). A mixed inequality pattern was observed across countries, as the risk of overweight was higher among high educated men in most Eastern countries, in contrast to other parts of Europe (RR from 0.74 to 1.19, RDA from -27% to 20%). Male obesity showed more pronounced inequalities (RR = 1.22, RDA=18%), and a consistent pattern of higher risk among the low educated and wide variation across countries (RR from 1.20 to 2.18, RDA from 16% to 49%). Among women, significant inequalities in overweight were observed (RR = 1.23, RDA=21%), with a consistent pattern of higher risk among the lowest EL, and substantial variation across countries (RR from 1.06 to 1.53, RDA from 7% to 36%). Inequalities were even larger for female obesity, with average RR and RDA reaching 1.49 and 35%, and wider variation (RR from 1.35 to 2.77, RDA from 12% to 88%).

Conclusions

Social inequalities in weight status are widespread in Europe, but vary substantially between countries. Inequalities are larger among women. For male overweight, a reverse inequality is observed in most Eastern countries. This study allows countries to benchmark the inequalities observed nationally to the situation in other EU countries.

Key messages

Social inequalities in weight status are widespread in Europe. The pattern of social inequalities in overweight and obesity varies substantially by country and gender.

Factors associated with short term transitions in frailty status in the population ≥ 50 years of age

Background

Frailty is a clinical state that increases an individual's vulnerability and leads to chronic and complex medical needs in the older population. Transition to frailty is a dynamic and reversible process. Therefore, identification of determinants of transitions between frailty states is important for preventive action. This study assesses correlates of short time transitions in frailty states in the non-institutionalized population aged ≥ 50 years in Belgium.

Methods

404 respondents of the Belgian health interview survey 2018 belonging to the target age group participated in a subsequent health examination survey (average time lapse 53 days). At both time points frailty was assessed with the SHARE frailty instrument classifying respondents as robust, prefrail or frail according to Fried's phenotype. Physical, biomedical, mental, social and demographic determinants of transitions in frailty status were explored through relative risk ratios (RRR) from a backward stepwise multinomial regression analysis.

Results

Both upward and downward transitions occurred in 21% of the respondents. Transitions were more frequent in women. Being obese (RRR 1.93; 95%CI 1.02-3.67) and being unsatisfied with social contacts (RRR 4.35; 95%CI 1.59-11.86) were significantly associated with a transition to a less favorable frailty status. Activity limitations (RRR 0.30; 95%CI 0.13-0.68) and a high serum total/HDL-cholesterol ratio (RRR 0.19; 95%CI 0.04-0.79) were inversely associated with an improvement of the frailty status. No significant associations were found with age, education level, multimorbidity, mental health, quality of life, smoking, physical activity, hyperglycemia, hypertension and increased C-reactive protein.

Conclusions

Preventive action to delay or reverse the transition towards frailty should start from 50 years onwards and include nutritional advise, actions that facilitate people to participate in activities and initiatives to improve social networks of people.

Key messages

Obesity and a high serum total/HDL-cholesterol ratio are risk factors for developing frailty. Investing in a good social network and an environment which facilitates participation in activities is important to delay or reverse the evolution towards frailty.

Intracerebroventricular Cerliponase Alfa for Neuronal Ceroid Lipofuscinosis Type 2 Disease: Clinical Practice Considerations From US Clinics

BACKGROUND

Neuronal ceroid lipofuscinosis type 2 or CLN2 disease is a rare, autosomal recessive, neurodegenerative lysosomal storage disorder caused by tripeptidyl peptidase 1 deficiency. Cerliponase alfa, a recombinant human tripeptidyl peptidase 1 enzyme, is the first and only approved treatment for CLN2 disease and the first approved enzyme replacement therapy administered via intracerebroventricular infusion.

METHODS

A meeting of health care professionals from US institutions with experience in cerliponase alfa treatment of children with CLN2 disease was held in November 2018. Key common practices were identified, and later refined during the drafting of this article, that facilitate safe chronic administration of cerliponase alfa.

RESULTS

Key practices include developing a multidisciplinary team of clinicians, pharmacists, and coordinators, and institution-specific processes. Infection risk may be reduced through strict aseptic techniques and minimizing connections and disconnections during infusion. The impact of intracerebroventricular device design on port needle stability during extended intracerebroventricular infusion is a critical consideration in device selection. Monitoring for central nervous system infection is performed at each patient contact, but with flexibility in the degree of monitoring. Although few institutions had experienced positive cerebrospinal fluid test results, the response to a positive cerebrospinal fluid culture should be determined on a case-by-case basis, and the intracerebroventricular device should be removed if cerebrospinal fluid infection is confirmed.

CONCLUSIONS

The key common practices and flexible practices used by institutions with cerliponase alfa experience may assist other institutions in process development. Continued sharing of experiences will be essential for developing standards and patient care guidelines.

The association of positive mental health indicators and normal body weight, Belgian HIS 2018

Background

An important health promotion goal is to maintain a normal body weight. However, knowledge about positive mental health indicators that might be associated with normal weight is scarce. The aim is to study positive mental health indicators and normal weight in a cross-sectional national representative population sample.

Methods

Study participants included adults aged ≥ 18 year (n = 6643) of the Belgian Health Interview Survey (HIS) 2018. Mental health indicators were having no psychological distress (GHQ-12&lt;2), no self-reported anxiety or depression (EQ_5D), medium to high vitality (SF-36 vitality scale) and high to medium level of life satisfaction. BMI was calculated on self-declared height and weight. The associations were assessed through logistic regression taking into account confounding and effect modification by age, gender, educational level, health status, physical activity, daily eating of fruit and vegetables and daily consuming sugared soft drinks or sweet/salty snacks.

Results

50.1% had a BMI≥25. In the crude models, all indicators were negatively associated with being obese, but there was no association between having a normal weight (versus overweight and obesity) and absence of psychological distress, absence of anxiety and depression, and medium to high vitality. Medium to high level of life satisfaction was associated with normal weight in the fully adjusted model (OR 1.3; 95%CI 1.0-1.6) but when stratified, medium to high life satisfaction was associated with normal weight only among high educated women (OR 1.8; 95%CI 1.1-2.9), but not among men and low educated women. Surprisingly, among low educated women, having no psychological distress was negatively associated with normal weight (OR 0.7; 95%CI 0.5-0.9).

Conclusions

These preliminary results showed a variable impact of gender and educational levels on the association between positive mental health indicators and normal weight. Trends and distribution in society should be further explored.

Key messages

Although unequivocal associations with obesity, positive mental health is not clearly associated with normal body weight in today’s obesogenic society. The effect of a shift towards a higher BMI in society on mental health needs to be further explored.

Effectiveness of protective measures on dental care utilization: analysis from linked database

Background

Financial accessibility to healthcare is a cornerstone in the Belgian health care system. A whole range of financial protectives measures are applied to ensure accessibility to all residents by minimizing the medical costs including a higher reimbursement for vulnerable population groups and protective measures for people with high health expenses due to chronic diseases. This study examines the effectiveness of such protective measures on the use of dental care among a representative sample of Belgian adults.

Methods

Data from the participants of the Belgian health interview survey (BHIS) 2013 aged 18 years and over were individually linked with data from the Belgian compulsory health insurance data (BCHI), (n = 8,668). Multivariate logistic regression was applied to assess the impact of the financial measures on the use of dental care.

Results

Five percent of the population reported having delayed dental care in the past 12 months due to financial barriers. Results from the multivariate model show that irrespective of gender, age, and educational level, individuals who have preferential reimbursement are more likely to postpone their dental care (OR = 3.32, 95% CI: 1.87-5.92), while those who can account on measures for high health expenses due to chronic diseases are less likely to do so (but not significantly).

Conclusions

Findings suggest that vulnerable people have more postponement despite the fact that they have a preferential reimbursement and, high expenses as a result of chronic diseases are not associated with more postponement of dental care. More targeted financial interventions should be necessary to reduce postponement of dental service utilization.

Key messages

Current health interventions are not yet effective for vulnerable people in dental care use. High expenses as a result of chronic diseases are not associated with more postponement of dental care.

Randomized Clinical Trial of First-Line Genome Sequencing in Pediatric White Matter Disorders

OBJECTIVE

Genome sequencing (GS) is promising for unsolved leukodystrophies, but its efficacy has not been prospectively studied.

METHODS

A prospective time-delayed crossover design trial of GS to assess the efficacy of GS as a first-line diagnostic tool for genetic white matter disorders took place between December 1, 2015 and September 27, 2017. Patients were randomized to receive GS immediately with concurrent standard of care (SoC) testing, or to receive SoC testing for 4 months followed by GS.

RESULTS

Thirty-four individuals were assessed at interim review. The genetic origin of 2 patient's leukoencephalopathy was resolved before randomization. Nine patients were stratified to the immediate intervention group and 23 patients to the delayed-GS arm. The efficacy of GS was significant relative to SoC in the immediate (5/9 [56%] vs 0/9 [0%]; Wild-Seber, p < 0.005) and delayed (control) arms (14/23 [61%] vs 5/23 [22%]; Wild-Seber, p < 0.005). The time to diagnosis was significantly shorter in the immediate-GS group (log-rank test, p = 0.04). The overall diagnostic efficacy of combined GS and SoC approaches was 26 of 34 (76.5%, 95% confidence interval = 58.8-89.3%) in <4 months, greater than historical norms of <50% over 5 years. Owing to loss of clinical equipoise, the trial design was altered to a single-arm observational study.

INTERPRETATION

In this study, first-line GS provided earlier and greater diagnostic efficacy in white matter disorders. We provide an evidence-based diagnostic testing algorithm to enable appropriate clinical GS utilization in this population. ANN NEUROL 2020;88:264-273.

PLPHP deficiency: clinical, genetic, biochemical, and mechanistic insights

Biallelic pathogenic variants in PLPBP (formerly called PROSC) have recently been shown to cause a novel form of vitamin B6-dependent epilepsy, the pathophysiological basis of which is poorly understood. When left untreated, the disease can progress to status epilepticus and death in infancy. Here we present 12 previously undescribed patients and six novel pathogenic variants in PLPBP. Suspected clinical diagnoses prior to identification of PLPBP variants included mitochondrial encephalopathy (two patients), folinic acid-responsive epilepsy (one patient) and a movement disorder compatible with AADC deficiency (one patient). The encoded protein, PLPHP is believed to be crucial for B6 homeostasis. We modelled the pathogenicity of the variants and developed a clinical severity scoring system. The most severe phenotypes were associated with variants leading to loss of function of PLPBP or significantly affecting protein stability/PLP-binding. To explore the pathophysiology of this disease further, we developed the first zebrafish model of PLPHP deficiency using CRISPR/Cas9. Our model recapitulates the disease, with plpbp-/- larvae showing behavioural, biochemical, and electrophysiological signs of seizure activity by 10 days post-fertilization and early death by 16 days post-fertilization. Treatment with pyridoxine significantly improved the epileptic phenotype and extended lifespan in plpbp-/- animals. Larvae had disruptions in amino acid metabolism as well as GABA and catecholamine biosynthesis, indicating impairment of PLP-dependent enzymatic activities. Using mass spectrometry, we observed significant B6 vitamer level changes in plpbp-/- zebrafish, patient fibroblasts and PLPHP-deficient HEK293 cells. Additional studies in human cells and yeast provide the first empirical evidence that PLPHP is localized in mitochondria and may play a role in mitochondrial metabolism. These models provide new insights into disease mechanisms and can serve as a platform for drug discovery.

The association between frailty and satisfaction with social contacts in the general older population

Background

As a result of the demographic evolution, the proportion of older people will continue to increase in the coming decades. Frailty among elderly is one of the important challenges that Europe is facing. From a biomedical, perspective frailty is considered as a clinical syndrome that increases vulnerability. However, the role of social contacts in relation to frailty needs to be investigated. In this study, we assessed the association between frailty and perceived satisfaction with social contacts in a sample of the general older population.

Methods

This study was conducted on a representative sample of 2364, both institutionalized and non-institutionalized older participants (≥65 years) from the Belgian Health Interview Survey 2018. Frailty was assessed with the instrument used in the Survey of Health Ageing and Retirement in Europe (SHARE) including dimensions of the Fried phenotype: exhaustion, weight loss, muscle strength, weakness and physical activity. The Oslo-3 Social Support Scale (OSS-3) was used to assess perceived quality of social support. Logistic regression was used to determine the association between frailty status and satisfaction with social contacts while controlling for age, gender, region, educational attainment and household composition.

Results

The prevalence of frailty was 22.8% (95%CI:21.2-24.6). The results showed that elderly who are unsatisfied with their social contacts are more likely to be frail (OR(95%CI):4.65 (2.82-7.66)). In addition, being older ≥75 years (OR(95%CI):2.40 (1.68-3.43)), being female (OR(95%CI):2.48 (1.73-3.56)), having a lower education (OR(95%CI):2.57 (1.71-3.87)), living alone (OR(95%CI):1.58 (1.10-2.27)) were associated with frailty.

Conclusions

Frailty is associated with living alone and being unsatisfied with the social contacts, among older people in Belgium. These findings confirm that the social component should be taken into account in strategies to reduce frailty in the general older population.

Key messages

Frailty is associated with living alone and being unsatisfied with the social contacts, among older people in Belgium. The social component should be taken into account in strategies to reduce frailty in the general older population.

Predictors of nursing-home entry for elders in Belgium

Background

Due to the aging of the population the demand for long-term care services is expected to rise during the coming years. For a better planning of health care resources policy makers have to be aware of risk factors associated to nursing home entry (NHE). The present study aims to identify predictors of NHE in a representative sample of Belgian community dwelling older residents.

Methods

Date from the participants of the Belgian health interview survey (BHIS) 2013 aged 65 years and over were individually linked with longitudinal data from the Belgian compulsory health insurance data (BCHI) over a 5-year period (2012-2017). Institutionalized BHIS participants were excluded, resulting in a final database of 1,927 individuals. A multivariate Cox proportional hazards model was fit to estimate the hazard of NHE. The model examined the hazard of NHE over the follow-up period in function of predisposing, enabling and need variables observed at baseline. All analyses were done using SAS 9.3 taking into account the survey design settings.

Results

Over the follow-up period, 169 out of 1,927 individuals entered in NH (56% males, mean age =74.7±0.25). Significant predictors of NHE were older age (hazard ratio (HR) =2.40, CI = 1.23-4.67 and HR = 6.19, 95% CI = 2.75-13.92, respectively for 75-84 years and 85+ years compared to 65-74 years), living condition (HR = 4.28, 95% CI = 1.01-18.19 for living alone), severity of limitation in ADLs (HR = 2.61, 95% CI = 1.39-4.88 for moderate limitation and HR = 2.40, 95% CI = 1.10-5.26 for severe limitation, compared to those without limitation).

Conclusions

Apart from age and living condition, the ADLs limitations were the strongest predictors of NHE. Public health action to reduce NHE of older people should first of all focus on preventive action at middle age which will reduce activity limitations at later age.

Key messages

Risk profiles for NHE are highly dependent individuals. NH should be more specialized with qualified professionals.

Severity Assessment in CDKL5 Deficiency Disorder

BACKGROUND

Pathologic mutations in cyclin-dependent kinase-like 5 cause CDKL5 deficiency disorder, a genetic syndrome associated with severe epilepsy and cognitive, motor, visual, and autonomic disturbances. This disorder is a relatively common genetic cause of early-life epilepsy. A specific severity assessment is lacking, required to monitor the clinical course and needed to define the natural history and for clinical trial readiness.

METHODS

A severity assessment was developed based on clinical and research experience from the International Foundation for CDKL5 Research Centers of Excellence consortium and the National Institutes of Health Rett and Rett-Related Disorders Natural History Study consortium. An initial draft severity assessment was presented and reviewed at the annual CDKL5 Forum meeting (Boston, 2017). Subsequently it was iterated through four cycles of a modified Delphi process by a group of clinicians, researchers, industry, patient advisory groups, and parents familiar with this disorder until consensus was achieved. The revised version of the severity assessment was presented for review, comment, and piloting to families at the International Foundation for CDKL5 Research-sponsored family meeting (Colorado, 2018). Final revisions were based on this additional input.

RESULTS

The final severity assessment comprised 51 items that comprehensively describe domains of epilepsy; motor; cognition, behavior, vision, and speech; and autonomic functions. Parental ratings of therapy effectiveness and child and family functioning are also included.

CONCLUSIONS

A severity assessment was rapidly developed with input from multiple stakeholders. Refinement through ongoing validation is required for future clinical trials. The consensus methods employed for the development of severity assessment may be applicable to similar rare disorders.

An Objective Method for Evaluating Next-Generation Sequencing Panels

PURPOSE

Next-generation sequencing panels are particularly useful in identifying genetic diagnoses in patients with nonspecific clinical findings by allowing for analysis of many genes at once. The purpose of this study was to develop a simple, objective system to evaluate the quality of available next-generation sequencing panels.

METHODS

A list of potentially important features of next-generation sequencing panels generated from the literature was evaluated for accessibility and objectivity and distilled to a "core" set of quality features. This was then applied to a clinical setting using the example of epilepsy panels. Panels at 8 laboratories were rated based on several objective measures to create a scoring system that differentiated between labs in a clinically meaningful way.

RESULTS

There was substantial variability in 6 "core" test criteria, allowing for creation of a scoring system that clearly distinguished labs based on identified strengths and weaknesses of each panel.

CONCLUSION

We have demonstrated an objective method for comparing next-generation sequencing panels that can be applied or adapted to any clinical phenotype for which genetic testing is available. This method offers an unbiased approach to determining the ideal test for a given indication at a given time.

Genetic testing in a cohort of patients with potential epilepsy with myoclonic-atonic seizures

Epilepsy with myoclonic-atonic seizures (EMAS) accounts for 1-2% of all childhood-onset epilepsies. EMAS has been shown to have an underlying genetic component, however the genetics of this disorder is not yet well understood. The purpose of this study was to review genetic testing results for a cohort of EMAS patients. A retrospective chart review was conducted for 77 patients evaluated at Children's Hospital Colorado with a potential diagnosis of EMAS. Genetic testing and biochemical testing was reviewed. Family history data was also collected. Seventy-seven percent of the cohort had at least one genetic test performed, and a molecular diagnosis was reached for six patients. Thirty-seven patients had a microarray, six of which identified a copy number variant. Only one was felt to contribute to the phenotype (2p16.3 deletion including NRXN1). Fifty-one patients had an epilepsy panel, two of which were positive (likely pathogenic variant in SCN1A, pathogenic variant in GABRG2). Of the six patients who had whole exome sequencing, two were negative, three were positive or likely positive, and one had multiple variants not felt to explain the phenotype. While EMAS is widely accepted to have a strong genetic component, the diagnostic yield of genetic testing remains low. This may be because several genes now thought to be associated with EMAS are not included on the more commonly ordered epilepsy panels, or have only recently been added to them.