Pediatric-onset Multiple Sclerosis Research Articles

Six-Minute Walk as a Measure of Walking Capacity and Endurance in Patients With Pediatric-Onset Multiple Sclerosis.

Despite low levels of disability, youth with pediatric-onset multiple sclerosis (POMS) engage in less physical activity compared with peers. The contribution of walking capacity, endurance, behavior, and MS comorbidities remains relatively undefined and may provide valuable insights into the limitations toward physical activity in youth with MS. The primary objective of this study was to investigate differences in walking capacity, endurance, and real-world behaviors of daily activity between youth with POMS and controls. Youth diagnosed with MS prior to 18 years and aged 21 years or younger were recruited in addition to healthy controls. Participants completed questionnaires to quantify fatigue, depression, and physical activity levels and the timed 2- and 6-minute walk (6MW) as an assessment of walking capacity and endurance. Participants completed questionnaires to quantify fatigue, depression, and physical activity levels. Participants also completed the timed 2- and 6-minute walk (6MW) as an assessment of walking capacity and endurance and were sent home with a waist-worn accelerometer to assess real-world walking behavior. Forty-five patients with POMS and 85 control participants were enrolled. The POMS cohort had a mean age of 16.9 ± 2.7 years, with a mean disease duration of 2.8 ± 2.6 years. A greater proportion of the POMS cohort was overweight/obese compared with controls (75% vs 33%). Participants with MS walked a significantly shorter distance in 6 minutes compared with controls (1,848 feet vs 2,134 feet, p < 0.0001) and, unlike controls, were unable to accelerate to their peak speed at the end of the 6MW. Body mass index category and MS disease significantly affected 6MW performance. Using continuous accelerometry, participants with MS spent less time in moderate-to-vigorous physical activity compared with controls (20.4 vs 35.4 min/d, p = 0.0003). The POMS cohort reported significantly higher levels of depression and fatigue but self-reported similar levels of daily physical activity as controls. Youth with POMS exhibit slower 6MW performance and less daily engagement in moderate-to-vigorous physical activity, suggesting limitations in functional walking capacity, endurance, and daily activity behavior. Limitations in walking endurance and capacity are most prominent in those youth who are overweight/obese and living with MS. This study provides Class III evidence that, compared with healthy controls, patients with POMS walk shorter distances on the 6MW test, are less able to accelerate to peak speed at the end of the test, and are less physically active.

Frequency of myelin oligodendrocyte glycoprotein antibodies in pediatric onset multiple sclerosis

BackgroundMyelin oligodendrocyte glycoprotein antibodies (MOG-Ab) are associated with acute demyelinating syndromes and only rarely detected in multiple sclerosis (MS). As MOG-Ab associated disease is common in childhood, we speculated young patients might be more likely to produce MOG-Ab and investigated the frequency of MOG-Ab seropositivity in pediatric onset MS (POMS). Material and methodsPatients who experienced their first acute demyelinating event before age 18 years and were diagnosed with MS during follow-up were included in this single-center study. Patient data were retrieved from clinical records. Serum samples obtained and frozen at clinical visits were analyzed for MOG-Ab by a live cell-based assay (CBA) measuring delta mean fluorescence intensity (MFI) and MFI ratio. The control group consisted of patients referred to pediatric neurology for headache or vertigo and who had no neurological disorder (n = 48). Another control group consisted of patients with systemic inflammatory disorders systemic lupus erythematosus (n = 17) and juvenile idiopathic arthritis (n = 13) diagnosed in the rheumatology clinic. ResultsThe patient group (n = 122, F/M: 90/32, mean age 17.8 ± 2.6 years) were initially diagnosed as: MS, 62/122 (50.8%), clinically isolated syndrome, 43/122 (35.2%), radiologically isolated syndrome, 9/122 (7.3%), and acute disseminated encephalomyelitis 8/122 (6.5%). All received the final diagnosis of POMS. Serum was sampled 22.4 ± 29.2 (0–132) months after the first episode. None of the control groups had MOG-Ab positivity while 2/122 (1.6%) POMS cases had MOG-Abs, and a third patient had positive MFI and a MFI ratio slightly below the cut-off. These three patients’ initial and final diagnoses were MS, their annualized relapsing rates (ARRs) were 0.4–0.6, and most recent Expanded Disability Status Scale was 0. ConclusionLow titers of MOG-Ab can be detected in a small number of POMS patients at similar frequency with adult MS. Our POMS cases with MOG-Abs presented brainstem-cerebellar findings or seizures and had low ARR. Further series and longer follow-up will define whether these cases differ significantly from MOG-Ab negative POMS cases.

Evaluation of Self-Efficacy and Health-Related Quality of Life in Pediatric-Onset Multiple Sclerosis Patients

Objective: To assess the self-efficacy level and health-related quality of life in pediatric-onset multiple sclerosis (POMS) patients. Material and Methods: A cross-sectional study was conducted between January-April 2022 at Hacettepe University Department of Pediatric Neurology using The Pediatric Rating of Chronic Illness Self-Efficacy (PRCISE) Scale and Pediatric Quality of Life Inventory (PedsQL). Results: Twenty-nine POMS patients with a median age of 16.4 years (F/M: 20/9) were included in the study. The mean PRCISE Scale score was 101.8±22.4 and the mean PedsQL score was 66.5±16.2. Both scores were lower than previously reported in the literature. Conclusion: Lower self-efficacy and HRQoL levels might be attributed to fatigue which is common in POMS. The impact of the COVID-19 pandemic on mental health and quality of life should be addressed in patients with POMS.

Quantitative Meta-analyses of Cognitive Abilities in Children With Pediatric-onset Multiple Sclerosis.

Pediatric-onset multiple sclerosis (POMS), is the manifestation of multiple sclerosis in individuals before 18years of age. About a third of children with POMS show some form of lower cognitive performance. The purpose of this study is to examine using quantitative meta-analyses the effect size of altered performance between children with and without POMS on overall intelligence quotient (IQ), information processing speed, and language functions. We searched the literature for studies that reported scores on cognitive tests administered to children with and without POMS. Studies were systematically reviewed using PRISMA guidelines. We analyzed data from 14 studies that examined 1283 children with and without POMS when cognitive categories consisted of five or more studies. Effect sizes, publication bias and potential confounds were considered. Significant cognitive differences are revealed for all categories with the strongest effect observed for overall IQ. A moderate effect is observed for information processing speed, and small effects for verbal fluency and verbal memory. Cognitive abilities present differently in children with POMS and a better understanding of this manifestation will inform intervention and remediation tools that can improve clinical and educational practice for the benefit of children with POMS.

Assessment of cervical spinal cord volume in pediatric-onset multiple sclerosis

PurposeSeveral studies of adult-onset multiple sclerosis (AOMS) patients have demonstrated that spinal cord volume loss is associated with disease progression and clinical disability. However, complementary studies of young patients with pediatric-onset multiple sclerosis (POMS) are lacking. Our retrospective study aimed to assess spinal cord volume in POMS patients compared with that in healthy controls. MethodsCervical spinal cord magnetic resonance images were evaluated for 20 POMS patients and 20 age- and sex-matched controls. Cross-sectional areas (CSAs) were measured at C2 and C7, along with the spinal cord average segmental area (CASA). The POMS group was further subdivided based on the presence or absence of spinal cord lesions, specifically C2 lesions. Pairwise area and volume comparisons were made across the different groups. ResultsNo significant difference was found in CASA and CSA at C2 and C7 between POMS patients and comparative controls. However, CASA, CSA at C7, and estimated spinal cord volume were significantly lower in a small subset of POMS patients with C2 lesions (3 patients) than in controls (P = 0.001, 0.02, and 0.001, respectively). ConclusionNo significant difference was found in spinal cord areas and volumes between POMS patients and controls. This finding contrasts with spinal cord volume measurements in AOMS patients.

Newer disease modifying treatments in pediatric onset multiple sclerosis: Experience from a single center.

Disease modifying treatments (DMTs) for multiple sclerosis include injectable drugs (iDMTs) like interferons (IFNs) or glatiramer acetate (GA), and newer agents (nDMTs) in oral and intravenous forms. nDMTs are usually applied in escalation and less frequently as initial treatment in pediatric-onset (POMS). We intended to evaluate the effect of nDMTs in comparison with iDMTs by retrospective examination of our patients with POMS. Clinical records of POMS cases who received nDMTs either as escalation or initial treatment and who had at least 12 months' follow-up in our clinic were examined in two groups: patients who were started on iDMTs and later switched to nDMTs (Group A), and those who received nDMTs from the beginning (Group B). Presenting symptoms, annualized relapsing rate (ARR), recent Expanded Disability Status Scale (EDSS), lesion load and presence of contrast enhancing (CE) lesions on magnetic resonance imaging (MRI) were compared. Total 43 patients were included: 33 in Group A and 10 in Group B. Age at onset, female/male ratio, duration since disease onset and duration under nDMT were similar in both groups. Initial involvement was predominantly brainstem and cerebellar in Group A and sensorial, brainstem/cerebellar, and optic nerve in Group B. The most frequently used nDMT was fingolimod in Group A (n=17, 51.5%) and teriflunomide (n=6, 60%) in Group B. Median ARR before any treatment was 2 in Group A and 1.5 in Group B (p>0.05); it decreased to median 1 under iDMTs in Group A and to 0 under nDMTs. Mean follow-up was 6.7±5 years (1-19, median 6 years) in Group A and 3.9±3.7 years (range 1-12, median 2 years) in Group B. At the latest follow-up median EDSS scores were 1 in Group A and 0 in Group B. ARR had increased and lesion load on MRI went up progressively in both groups during follow-up. However, the rate of patients with CE lesions diminished in Group B. This single-center study of POMS shows the ARR decreases under any treatment, more markedly under nDMTs, and nDMTs reduce the rate of patients with CE lesions on MRI without a clear effect on lesion load. The ARR tends to increase after the first 2 years of both iDMT and nDMT, suggesting a re-evaluation at that time. The ARR decreases shorty after treatment is changed from an iDMT to a nDMT.

The Outcome of COVID-19 in Pediatric-Onset Multiple Sclerosis Patients

BackgroundThe pathogenesis of multiple sclerosis (MS) involves immune-mediated mechanisms, and disease-modifying therapies (DMTs) administered in MS have immunomodulatory effects. The concern about MS patients' susceptibility to coronavirus disease 2019 (COVID-19) has prompted several studies based on clinical observations and questionnaires. Information about COVID-19 in pediatric-onset multiple sclerosis (POMS) is scarce. The objective of this study was to collect information on the experience of POMS patients with COVID-19 during the pandemic. MethodsThis cross-sectional study was conducted with POMS patients diagnosed at Hacettepe University Pediatric Neurology Department and under 23 years of age between October 1 and December 31, 2021. Those who experienced COVID-19 or had a history of contact and were found seropositive for COVID-19 were evaluated for the severity of COVID-19, disability, treatment status, and comorbidities. ResultsAmong the 101 POMS patients, 13 reported having had COVID-19 and five were exposed and seropositive but clinically asymptomatic. Of these 18 patients, 14 were ≤18 years of age at the time of the study. All 13 patients (72%) reported mild symptoms without hospitalization or respiratory support. Four of 18 had a neurological disability (Expanded Disability Status Scale [EDSS] scores ranging between 1 and 7.5), while the remaining had a score of 0. The outcome of COVID-19 was not affected by DMTs, neurological disabilities, and comorbidities. ConclusionsIn this single-center POMS series, the small subgroup of patients who had contacted the SARS-CoV-2 virus or developed COVID-19 had reported no or mild symptoms. This may be partly related to the infrequent use of rituximab in this group. Our results corroborate those in adult-onset MS where no increased risk is reported for patients whose EDSS scores are <6 and who are not on B cell–depleting DMTs. Although less frequently than in adult MS, immunosuppressive DMTs may be needed in POMS; therefore, the importance of appropriate vaccination is to be underlined.

P.081 Evolving treatment of pediatric-onset multiple sclerosis in Alberta

Background: Pediatric-onset multiple sclerosis (MS) is associated with a high rate of disease activity. However, only a single DMT – fingolimod – has been approved by Health Canada for children, in 2018. In this study, we describe trends in the treatment of pediatric-onset MS in Alberta. Methods: We performed a retrospective review of Alberta administrative health databases, identifying cases of MS under 19 years of age from January 1, 2011 - December 31, 2020. Pharmacy dispenses of MS DMTs were identified by Anatomical Therapeutic Chemical classification code and grouped as injectables (glatiramer acetate, interferon-beta) or newer agents (all others). Results: 79 incident cases of pediatric MS were identified during the study period. 47/79 (59%) had at least one DMT dispense, with the first dispense occurring a median 263 days (IQR 134.5-988) from the index date at a median age of 17.2 years (IQR 16.0-18.6). Injectables accounted for all initial DMT dispenses &lt; 19 years of age prior to 2019, while from 2019-2020 injectables accounted for only 3/15 (20%) initial dispenses, with rituximab (5/15, 33%) being the most common initial DMT in those years. Conclusions: The treatment of children with MS in Alberta has rapidly evolved, shifting shift towards earlier treatment using newer high-efficacy agents.

Interrogating large multiple sclerosis registries and databases: what information can be gained?

Although substantial progress has been made in understanding the natural history of multiple sclerosis (MS) and the development of new therapies, many questions concerning disease behavior and therapeutics remain to be answered. Data generated from real-world observational studies, based on large MS registries and databases and analyzed with advanced statistical methods, are offering the scientific community answers to some of these questions that are otherwise difficult or impossible to address. This review focuses on observational studies published in the last 2 years designed to compare the effectiveness of escalation vs. induction treatment strategies, to assess the effectiveness of treatment in pediatric-onset and late-onset MS, and to identify the clinical phenotype of secondary progressive (SP)MS. The main findings originating from real-world studies suggest that MS patients who will qualify for high-efficacy disease-modifying therapies (DMTs) should be offered these as early as possible to prevent irreversible accumulation of neurological disability. Especially pediatric patients derive substantial benefits from early treatment. In patients with late-onset MS, sustained exposure to DMTs may result in more favorable outcomes. Data-driven definitions are more accurate in defining transition to SPMS than diagnosis based solely on neurologists' judgment. Patients, physicians, industry, and policy-makers have all benefited from real-world evidence based on registry data, in answering questions of diagnostics, choice of treatment, and timing of treatment decisions.

Cognitive impairment in paediatric onset multiple sclerosis and its relation to thalamic volume and cortical thickness of temporal lobe by magnetic resonance imaging

BackgroundPediatric onset multiple sclerosis (POMS), defined as an age at onset younger than 18 years, which occurs in 5% of patients with MS. cognitive dysfunction is one of the prominent disabling sequelae of Multiple sclerosis. Brain volumetric studies by magnetic resonance images revealed the decline of whole and regional brain volumes along the disease course. This work aimed to investigate the relationship between cognitive impairment in pediatric MS patients with thalamic atrophy and cortical thickness of temporal lobe. This study included 50 patients who were diagnosed as POMS and 50 healthy control participants matched for age and sex. Both groups were compared for volumetric measurements of thalamic volumes and temporal lobes cortical thickness using a computerized program called FreeSurfer.MS group was evaluated for cognitive dysfunction using Arabic version of fifth edition of Standford–Benit test. A correlation between volumetric results and neuropsychological evaluation of MS group was done.ResultsOur study showed that the MS group has the lowest value regarding their thalamic volumes and their cortical thickness of temporal lobes in relation to the healthy control group, while there was a significant relation between cognitive impairment and decrease in thalamic volume and specific areas in cortical thickness, such as superior temporal thickness, middle temporal thickness, inferior temporal thickness, fusiform thickness and para hippocampal thickness of temporal lobe in pediatric onset MS patients.ConclusionsPOMS affects specific brain areas such as thalamus and cortical thickness of temporal lobes regarding their volume and thickness which influence the neuropsychological evaluation detected by Standford–Benit test.

Social Networks in Pediatric-Onset Multiple Sclerosis are Associated with Less Negative Peer Pressure (P18-4.002)

Social Networks in Pediatric-Onset Multiple Sclerosis are Associated with Less Negative Peer Pressure (P18-4.002)

Assessment of cervical spinal cord volume in pediatric-onset multiple sclerosis (P15-4.004)

Assessment of cervical spinal cord volume in pediatric-onset multiple sclerosis (P15-4.004)

Academic Underachievement is Common in Pediatric-Onset Multiple Sclerosis (P4-4.006)

Academic Underachievement is Common in Pediatric-Onset Multiple Sclerosis (P4-4.006)

Quality of life in pediatric-onset multiple sclerosis: Different disease course, different impact, different measurement approach needed

ObjectiveTo understand the impact of pediatric multiple sclerosis (MS), health-related quality of life (HRQL) measures have been used. However, specific areas of concern of youths with MS are not known. The objective of this study was to contribute content for inclusion in a new condition-specific measure of the life impact of MS for children and adolescents. MethodsA patient engagement framework was used, and an online survey was developed using the Patient Generated Index (PGI). Text threads generated by the PGI were mapped to the International Classification of Functioning, Disability, and Health (ICF) and the Comprehensive ICF Core Set for MS. ResultsA total of 20 people completed the PGI survey of which 11 were youths with MS aged 14 to 22 years. Over 75% of the areas nominated by youths with MS were related to activities and participation and approximately 20% were related to body function. In contrast, 60% of the areas nominated by parents were related to body function. This finding indicated that a measure of life impact would need to include both impairments associated with MS and important activities and roles. This new approach has a disability component covers MS-related impairments and is completed using the PGI system where the youth select disability areas affected by MS, rate, and prioritize each area for improvement. The "quality of life" component queries those areas that are going well. ConclusionThis new measurement approach could prove useful in overcoming challenges in developing condition-specific measures for rare conditions.

Natalizumab therapy in patients with pediatric-onset multiple sclerosis in Greece: clinical and immunological insights of time-long administration and future directions-a single-center retrospective observational study.

Pediatric-onset multiple sclerosis (MS, POMS) accounts for 3-5% of all MS cases and is characterized by a highly inflammatory profile, often warranting treatment with high-efficacy agents. Our aim is to present real-world data of a series of 18 Hellenic POMS patients treated with natalizumab (NTZ) either as adolescents or as adults, after high disease activity has efficiently subsided. Clinical and imaging/laboratory data from 18 POMS patients who have received at least one NTZ infusion were selected in this single-center retrospective observational study. Human leukocyte antigen (HLA) genotyping was performed with standard low-resolution sequence-specific oligonucleotide techniques. Eighteen patients with a mean age of disease onset of 15.3 ± 2.4years were treated with NTZ with a mean of 51.7 ± 46.4 infusions, 6 as adolescents and 12 as adults. 22.2% were treatment naïve. At the end of the observational period, patients of both groups remained relapse-free, with no radiological activity and significantly reduced disability accumulation. No evidence of disease activity (NEDA)-3 status was achieved in 66.7% of all patients, 58.3% in the adult-treated, and 83.3% in the adolescent-treated POMS patients. NTZ was generally well tolerated. Only 5 adverse events were observed, in 3 patients who were carriers of the HLA-DRB1*15 (HLA-DRB1*15/HLA-DRB1*11 and HLA-DRB1*15/HLA-DRB1*13 genotypes), 1 homozygous for the HLA-DRB1*03 allele and 1 heterozygous for HLA-DRB1*04 and HLA-DRB1*16 alleles. NTZ is highly efficacious and mostly safe for POMS patients with high disease activity in all age groups. The role of immunogenetics in personalized patient evaluation and treatment needs to be further investigated.

Spotlight on the April 19 Issue

#### Notable in Neurology This Week This issue features an article that explores racial and ethnic disparities in the rate of thrombolytic declination among patients with acute ischemic stroke; another evaluates the long-term cognitive function and socioprofessional attainment of people with pediatric-onset multiple sclerosis. A featured Historical Neurology article discusses Jean-Louis Prévost's contributions to the study of oculomotor functions. ### Cerebral Microbleeds, Cerebral Amyloid Angiopathy, and Their Relationships to Quantitative Markers of Neurodegeneration ![Graphic][1]</img> In this study on the association of cerebral microbleeds (CMBs) and cerebral amyloid angiopathy (CAA) with morphologic markers of neurodegeneration, … [1]: /embed/inline-graphic-1.gif

Long-term Cognitive Outcomes and Socioprofessional Attainment in People With Multiple Sclerosis With Childhood Onset.

Patients with pediatric-onset multiple sclerosis (MS) can be especially vulnerable to cognitive impairment (CI) due to the onset of MS during a critical period for CNS development and maturation. The objective of this longitudinal study was to assess long-term cognitive functioning and socioprofessional attainment in the Italian pediatric MS cohort, previously assessed at baseline and 2 and 5 years. The 48 patients evaluated at the 5-year assessment were screened for inclusion. All participants were assessed with a cognitive test battery exploring 4 different cognitive abilities. Depression, fatigue, and socioprofessional attainment were also assessed. Mean cognitive z scores were calculated for the whole cohort, and their evolution over time was analyzed with an analysis of variance for repeated measurements test. Predictors of cognitive worsening or improvement were assessed with a linear mixed-model analysis. Thirty-three participants were included (mean follow-up 12.8 ± 0.8 years). The global cognitive performance worsened at year 2 and improved at year 5, although the z score remained significantly lower than at baseline (-0.9 ± 1.2 vs -0.3 ± 0.9, p = 0.002). There was no significant variation between years 5 and 12 (-0.7 ± 1.1, p = 0.452). Higher IQ (>90) at baseline (effect 0.3, 95% CI 0.1-0.5, p = 0.017) and lower number of relapses in the 2 years before baseline (effect -0.1, 95% CI -0.1 to 0.1, p = 0.025) predicted better cognitive performances. Eighteen (54.5%) patients failed at least 2 tests compared with healthy controls and were defined as cognitively impaired. The presence of CI predicted worse socioprofessional attainment (β = 4.8, 95% CI 1.4-8.2, p = 0.008). The longitudinal cognitive trajectory in pediatric-onset MS has a heterogeneous course over time, with a decline in the first years followed by a partial recovery over the long term. However, at the last follow-up evaluation, the proportion of impaired patients was more than double compared with baseline, with a negative impact on the individual's socioprofessional attainment in adulthood. This study underscores how cognitive reserve may partially mitigate the negative effects of brain damage, highlighting the critical importance of intellectual enrichment early during the disease course.

Personalized Disease Monitoring in Pediatric Onset Multiple Sclerosis Using the Saliva Free Light Chain Test.

BackgroundDevelopment of new safe methods of monitoring disease activity in the pediatric onset multiple sclerosis (POMS) is a challenging task, especially when trying to refrain from frequent MRI usage. In our recent study, the saliva immunoglobulin free light chains (FLC) were suggested as biomarkers to discriminate between remission and active MS in adults.ObjectivesTo assess utility of saliva FLC measurements for monitoring disease activity in POMS.MethodsWe used semiquantitative Western blot analysis to detect immunoreactive FLC monomers and dimers and to calculate the intensity of their bands. Statistical tests included Firth logistic regression analysis suitable for small sample sizes, and Spearman’s non-parametric correlation.ResultsIn naive POMS patients, the saliva levels of FLC in relapse were significantly higher than those in remission. Significant correlation was found between FLC levels (monomers, dimers or both) and the load of enhanced lesions in MRI scans. FLC levels may be reduced under treatment, especially as result of corticosteroids therapy. Follow-up of individual patients showed the correspondence of changes in the FLC levels to MRI findings.ConclusionsOur results show the potential of the non-invasive saliva FLC test, as a new tool for monitoring the disease activity in POMS.

Six-Minute Walk Performance and Related Factors in Pediatric-Onset Multiple Sclerosis

To investigate functional exercise capacity and its relationship between physical activity levels, muscle strength, balance, fatigue, and quality of life in patients with pediatric-onset multiple sclerosis. Fifteen patients with pediatric-onset multiple sclerosis were included. The 6-minute walk test was used to determine functional exercise capacity and walking distance. The Godin Leisure-Time Exercise Questionnaire and pedometer were used to evaluate physical activity, Timed-Up and Go for dynamic balance, isokinetic testing for lower extremity muscle strength, Fatigue Severity Scale for fatigue, and the Pediatric Quality of Life Inventory (PedsQL) for quality of life. The 6-minute walking distance was positively correlated with GLTEQ and the School-Work subgroup score of the PedsQL-Self-report, and negatively correlated with Timed-Up and Go and Fatigue Severity Scale. Dynamic balance, physical activity, and fatigue were significant predictors of 6-minute walking distance. Our results showed that 6-minute walk test is influenced by physical activity, dynamic balance, and fatigue, and related to quality of life in patients with pediatric-onset multiple sclerosis.

Stability of the gut microbiota in persons with paediatric-onset multiple sclerosis and related demyelinating diseases

Objective: Examine if the gut microbiota composition changes across repeated samples in paediatric-onset multiple sclerosis (MS) or monophasic-acquired demyelinating syndromes (monoADS). Methods: A total of 36 individuals (18 MS/18 monoADS) with ⩾2 stool samples were included. Stool sample-derived DNA was sequenced. Alpha/beta diversities and genus-level taxa were analysed. Results: Mean ages at first sample procurement (MS/monoADS) = 18.0/13.8 years. Median time (months) between first/second samples = 11.2 and second/third = 10.3. Alpha/beta diversities did not differ between stool samples (p > 0.09), while one genus – Solobacterium did (p = 0.001). Conclusions: The gut microbiota composition in paediatric-onset MS and monoADS exhibited stability, suggesting that single stool sample procurement is a reasonable first approach.