Frequency of an intrathecal IgM synthesis and MRZ reaction in children with MS

BACKGROUND

Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the CNS. An intrathecal IgM synthesis is associated with a more rapid progression of MS and the intrathecal immune response to measles -, rubella -and varicella zoster virus (MRZR) which, if present, increases the likelihood of a diagnosis of MS in adults.

OBJECTIVE

To evaluate the frequency of an intrathecal IgM synthesis and MRZR in children with MS. MethodsChildren with MS and a data set including clinical and treatment history, MRI at onset, in addition to a CSF analysis, and determination of antibody index (AI) of measles, rubella, and zoster antibodies, were eligible. The presence of an intrathecal IgM synthesis and/or a positive MRZ reaction were compared to biomarkers of a more progressive disease course.

RESULTS

In 75 children with MS, OCBs were present in 93.3 %). 49,2 % experienced their first relapse within 6 months. 50.7 % had a total lesion load of more than 10 lesions in the first brain MRI. Spinal lesions were identified in 64 %. 23.5 % had a positive MRZR and 40.3 % an intrathecal IgM synthesis. No significant associations were detected between the presence of an intrathecal IgM synthesis and MRZR and parameters including the relapse rate in the first two years.

CONCLUSION

An intrathecal IgM synthesis and a positive MRZR are found in a subset of MS children but are not associated with markers associated with a poor prognosis.

Natural History and Developmental Trajectories of Individuals With Disease-Causing Variants in STXBP1

BACKGROUND AND OBJECTIVES

Pathogenic variants in STXBP1 are among the major genetic causes of neurodevelopmental disorders. Despite the increasing number of individuals diagnosed without a history of epilepsy, little is known about the natural history and developmental trajectories in this subgroup and endpoints for future therapeutic studies are limited to seizure control.

METHODS

We performed a cross-sectional retrospective study using standardized questionnaires for clinicians and caregivers of individuals with STXBP1-related disorders capturing medical histories, genetic findings, and developmental outcomes. Motor and language function were assessed using Gross Motor Function Classification System (GMFCS) scores and a speech impairment score and were compared within and across clinically defined subgroups.

RESULTS

We collected data of 71 individuals with STXBP1-related disorders, including 44 previously unreported individuals. Median age at inclusion was 5.3 years (interquartile range 3.5-9.3) with the oldest individual aged 43.8 years. Epilepsy was absent in 18/71 (25%) of individuals. The range of developmental outcomes was broad, including 2 individuals presenting with close to age-appropriate motor development. Twenty-nine of 61 individuals (48%) were able to walk unassisted, and 24/69 (35%) were able to speak single words. Individuals without epilepsy presented with a similar onset and spectrum of phenotypic features but had lower GMFCS scores (median 3 vs 4, p < 0.01) than individuals with epilepsy. Individuals with epileptic spasms were less likely to walk unassisted than individuals with other seizure types (6% vs 58%, p < 0.01). Individuals with early epilepsy onset had higher speech impairment scores (p = 0.02) than individuals with later epilepsy onset.

DISCUSSION

We expand the spectrum of STXBP1-related disorders and provide clinical features and developmental trajectories in individuals with and without a history of epilepsy. Individuals with epilepsy, in particular epileptic spasms, and neonatal or early-onset presented with less favorable motor and language functional outcomes compared with individuals without epilepsy. These findings identify children at risk for severe disease and can serve as comparator for future interventional studies in STXBP1-related disorders.

Development and preliminary validation of the Sleep Screening for Children and Adolescents with Complex Chronic Conditions (SCAC)

Children and adolescents with complex chronic conditions, including those with life-threatening or life-limiting conditions, are a heterogeneous population. Many individuals exhibit sleep abnormalities that are measurable by proxy questionnaires. No suitable instrument to assess the wide range of different complex chronic conditions is currently available. The aim of the present study was to develop a screening tool-the Sleep Screening for Children and Adolescents with Complex Chronic Conditions-to effectively obtain sleep behaviour information in this population. Following a mixed-method design, potential items for the Sleep Screening for Children and Adolescents with Complex Chronic Conditions questionnaire were defined through literature research and expert meetings. In a pre-test with N = 60 family and professional caregivers, the items' relevance and comprehensibility as well as the instrument's overall design were assessed. For the main test, N = 315 participants were recruited in three tertiary paediatric hospitals. A principal components analysis detected the questionnaire's scales. Item analysis focused on mean values, range, difficulty and discriminatory power. Convergent validation of the Sleep Screening for Children and Adolescents with Complex Chronic Conditions was assessed via correlations between scale items. Most patients had neurological or neuromuscular diseases. Four scales ("Falling and staying asleep", "Sleep-associated respiration and arousal", "Daytime sleepiness" and "Sleep-associated movements") emerged. The item analysis showed satisfactory discriminative power. In the preliminary validation, all scales correlated positively with a child's care level and with various sleep circumstances items. Three scales additionally correlated with the number of complex chronic condition diagnoses. This newly developed questionnaire can provide clinicians with first indications of possible sleep problems in a growing paediatric population.

QIL1-dependent assembly of MICOS complex-lethal mutation in C19ORF70 resulting in liver disease and severe neurological retardation

Seven subunits of the mitochondrial contact site and cristae junction (CJ) organizing system (MICOS) in humans have been recently described in function and structure. QIL1 (also named MIC13) is a small complex that is crucial for the maintenance and assembling of MICOS. A novel mutation of an essential splice site in the C19orf70 gene encoding QIL1 induces severe mitochondrial encephalopathy, hepatopathy and lactate acidosis consistent with psychomotor retardation. In addition, bilateral kidney stones were observed. Disassembly of MICOS complex subunits displays lack of MIC10-MIC26-MIC27-QIL1 subcomplex, resulting in aberrant cristae structure and a loss of cristae junctions and contact sites. In liver and muscle tissue, the activity of the respiratory chain complexes (OXPHOS) was severely impaired. Defects in MICOS complex do not only affect mitochondrial architecture, but also mitochondrial fusion, metabolic signalling, lipid trafficking and cellular electric homeostasis.