Long term follow-up in GAMT deficiency - Correlation of therapy regimen, biochemical and in vivo brain proton MR spectroscopy data.

GAMT deficiency is a rare autosomal recessive disease within the group of cerebral creatine deficiency syndromes. Cerebral creatine depletion and accumulation of guanidinoacetate (GAA) lead to clinical presentation with intellectual disability, seizures, speech disturbances and movement disorders. Treatment consists of daily creatine supplementation to increase cerebral creatine, reduction of arginine intake and supplementation of ornithine for reduction of toxic GAA levels. This study represents the first long-term follow-up over a period of 14 years, with detailed clinical data, biochemical and multimodal neuroimaging findings. Developmental milestones, brain MRI, quantitative single voxel 1H magnetic resonance spectroscopy (MRS) and biochemical analyses were assessed. The results reveal insights into the dose dependent effects of creatine/ornithine supplementation and expand the phenotypic spectrum of GAMT deficiency. Of note, the creatine concentrations, which were regularly monitored over a long follow-up period, increased significantly over time, but did not reach age matched control ranges. Our patient is the second reported to show normal neurocognitive outcome after an initial delay, stressing the importance of early diagnosis and treatment initiation.

Biallelic NUDT2 variants defective in mRNA decapping cause a neurodevelopmental disease.

Dysfunctional RNA processing caused by genetic defects in RNA processing enzymes has a profound impact on the nervous system, resulting in neurodevelopmental conditions. We characterized a recessive neurological disorder in 18 children and young adults from 10 independent families typified by intellectual disability, motor developmental delay and gait disturbance. In some patients peripheral neuropathy, corpus callosum abnormalities and progressive basal ganglia deposits were present. The disorder is associated with rare variants in NUDT2, a mRNA decapping and Ap4A hydrolysing enzyme, including novel missense and in-frame deletion variants. We show that these NUDT2 variants lead to a marked loss of enzymatic activity, strongly implicating loss of NUDT2 function as the cause of the disorder. NUDT2-deficient patient fibroblasts exhibit a markedly altered transcriptome, accompanied by changes in mRNA half-life and stability. Amongst the most up-regulated mRNAs in NUDT2-deficient cells, we identified host response and interferon-responsive genes. Importantly, add-back experiments using an Ap4A hydrolase defective in mRNA decapping highlighted loss of NUDT2 decapping as the activity implicated in altered mRNA homeostasis. Our results confirm that reduction or loss of NUDT2 hydrolase activity is associated with a neurological disease, highlighting the importance of a physiologically balanced mRNA processing machinery for neuronal development and homeostasis.

Pretreatment Neurofilament Light Chain Serum Levels, Early Disease Severity, and Treatment Response in Pediatric Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: High disease activity and frequent therapy failure in pediatric multiple sclerosis (MS) make prognostic biomarkers urgently needed. We investigated whether serum neurofilament light chain (sNfL) levels in treatment-naive pediatric patients with MS are associated with early disease severity and indicate treatment outcomes. METHODS: A retrospective cohort study of patients seen in the Göttingen Center for MS in Childhood and Adolescence, Germany. Inclusion criteria were MS diagnosis according to the McDonald criteria, MS onset <18 years, and available pretreatment serum sample. sNfL levels were analyzed using a single-molecule array assay. Associations with clinical and MRI evidence of disease severity at sampling were evaluated using the Spearman correlations and nonparametric tests for group comparisons. Correlations between pretreatment sNfL and annualized relapse and new T2 lesion rate on first-line therapy, and odd ratios for switch to high-efficacy therapy were assessed. RESULTS: A total of 178 patients (116 women [65%]) with a mean sampling age of 14.3 years were included in the study. Pretreatment sNfL levels were above the ≥90th percentile reported for healthy controls in 80% of patients (median 21.1 pg/mL) and correlated negatively with age, but no correlation was seen with sex, oligoclonal band status, or body mass index. High pretreatment sNfL levels correlated significantly with a high number of preceding relapses, a shorter first interattack interval, a high T2 lesion count, and recent gadolinium-enhancing lesions. Of interest, sNfL levels reflected more strongly MRI activity rather than clinical activity. Pretreatment sNfL levels also correlated significantly with the relapse rate and occurrence of new/enlarging T2 lesions while on first-line injectable therapy. Odds of future therapy escalation increased from 0.14 for sNfL below 7.5 pg/mL to 6.38 for sNfL above 15 pg/mL. In patients with a recent relapse, higher sNfL levels were associated with poorer recovery 3 months after attack. DISCUSSION: The results of this study have 3 important implications: First, pretreatment sNfL levels are a valuable biomarker for underlying disease activity in pediatric patients with MS. Second, pretreatment sNfL levels in pediatric patients with MS have a predictive value for the response to first-line therapy and the necessity of future therapy escalation. Third, high sNfL levels during a relapse are associated with poor recovery in this age group.

Evaluation of Novel Enhancer Compounds in Gentamicin-Mediated Readthrough of Nonsense Mutations in Rett Syndrome.

Rett syndrome (RTT), a severe X-linked neurodevelopmental disorder, is primarily caused by mutations in the methyl CpG binding protein 2 gene (MECP2). Over 35% RTT patients carry nonsense mutation in MECP2, making it a suitable candidate disease for nonsense suppression therapy. In our previous study, gentamicin was found to induce readthrough of MECP2 nonsense mutations with modest efficiency. Given the recent discovery of readthrough enhancers, CDX compounds, we herein evaluated the potentiation effect of CDX5-1, CDX5-288, and CDX6-180 on gentamicin-mediated readthrough efficiency in transfected HeLa cell lines bearing the four most common MECP2 nonsense mutations. We showed that all three CDX compounds potentiated gentamicin-mediated readthrough and increased full-length MeCP2 protein levels in cells expressing the R168X, R255X, R270X, and R294X nonsense mutations. Among all three CDX compounds, CDX5-288 was the most potent enhancer and enabled the use of reduced doses of gentamicin, thus mitigating the toxicity. Furthermore, we successfully demonstrated the upregulation of full-length Mecp2 protein expression in fibroblasts derived from Mecp2R255X/Y mice through combinatorial treatment. Taken together, findings demonstrate the feasibility of this combinatorial approach to nonsense suppression therapy for a subset of RTT patients.

Mutations in TAF8 cause a neurodegenerative disorder.

TAF8 is part of the transcription factor II D complex, composed of the TATA-binding protein and 13 TATA-binding protein-associated factors (TAFs). Transcription factor II D is the first general transcription factor recruited at promoters to assemble the RNA polymerase II preinitiation complex. So far disorders related to variants in 5 of the 13 subunits of human transcription factor II D have been described. Recently, a child with a homozygous c.781-1G>A mutation in TAF8 has been reported. Here we describe seven further patients with mutations in TAF8 and thereby confirm the TAF8 related disorder. In two sibling patients, we identified two novel compound heterozygous TAF8 splice site mutations, c.45+4A > G and c.489G>A, which cause aberrant splicing as well as reduced expression and mislocalization of TAF8. In five further patients, the previously described c.781-1G > A mutation was present on both alleles. The clinical phenotype associated with the different TAF8 mutations is characterized by severe psychomotor retardation with almost absent development, feeding problems, microcephaly, growth retardation, spasticity and epilepsy. Cerebral imaging showed hypomyelination, a thin corpus callosum and brain atrophy. Moreover, repeated imaging in the sibling pair demonstrated progressive cerebral and cerebellar atrophy. Consistently, reduced N-acetylaspartate, a marker of neuronal viability, was observed on magnetic resonance spectroscopy. Further review of the literature shows that mutations causing a reduced expression of transcription factor II D subunits have an overlapping phenotype of microcephaly, developmental delay and intellectual disability. Although transcription factor II D plays an important role in RNA polymerase II transcription in all cells and tissues, the symptoms associated with such defects are almost exclusively neurological. This might indicate a specific vulnerability of neuronal tissue to widespread deregulation of gene expression as also seen in Rett syndrome or Cornelia de Lange syndrome.

Effect of fingolimod on health-related quality of life in paediatric patients with multiple sclerosis: results from the phase 3 PARADIGMS Study.

Background: In the PARADIGMS Study, fingolimod demonstrated superior efficacy versus interferon (IFN) ß-1a and comparable overall incidence of adverse events but slightly higher rate of serious adverse events in patients with paediatric-onset multiple sclerosis (PoMS). Here, we report the health-related quality of life (HRQoL) outcomes from PARADIGMS. Methods: Patients with PoMS (N=215; aged 10-<18 years) were randomised to once-daily oral fingolimod (N=107) or once-weekly intramuscular IFN ß-1a (N=108). HRQoL outcomes were assessed using the 23-item Pediatric Quality of Life (PedsQL) scale that comprises Physical and Psychosocial Health Summary Scores (including Emotional, Social and School Functioning). A post hoc inferential analysis evaluated changes in self-reported or parent-reported PedsQL scores from baseline up to 2 years between treatment groups using an analysis of covariance model. Results: Treatment with fingolimod showed improvements versus IFN ß-1a on the PedsQL scale in both the self-reported and parent-reported Total Scale Scores (4.66 vs -1.16, p≤0.001 and 2.71 vs -1.02, p≤0.05, respectively). The proportion of patients achieving a clinically meaningful improvement in the PedsQL Total Scale Score was two times higher with fingolimod versus IFN ß-1a per the self-reported scores (47.5% vs 24.2%, p=0.001), and fingolimod was favoured versus IFN ß-1a per the parent-reported scores (37.8% vs 24.7%, p=non-significant). Group differences in self-reported Total Scale Scores in favour of fingolimod were most pronounced among patients who had ≥2 relapses in the year prior to study entry or who showed improving or stable Expanded Disability Status Scale scores during the study. Conclusion: Fingolimod improved HRQoL compared with IFN ß-1a in patients with PoMS as evidenced by the self-reported and parent-reported PedsQL scores.

A novel remitting leukodystrophy associated with a variant in FBP2.

Leukodystrophies are genetic disorders of cerebral white matter that almost exclusively have a progressive disease course. We became aware of three members of a family with a disorder characterized by a sudden loss of all previously acquired abilities around 1 year of age followed by almost complete recovery within 2 years. Cerebral MRI and myelin sensitive imaging showed a pronounced demyelination that progressed for several months despite signs of clinical improvement and was followed by remyelination. Exome sequencing did not-identify any mutations in known leukodystrophy genes but revealed a heterozygous variant in the FBP2 gene, c.343G>A, p. Val115Met, shared by the affected family members. Cerebral MRI of other family members demonstrated similar white matter abnormalities in all carriers of the variant in FBP2. The FBP2 gene codes for muscle fructose 1,6-bisphosphatase, an enzyme involved in gluconeogenesis that is highly expressed in brain tissue. Biochemical analysis showed that the variant has a dominant negative effect on enzymatic activity, substrate affinity, cooperativity and thermal stability. Moreover, it also affects the non-canonical functions of muscle fructose 1,6-bisphosphatase involved in mitochondrial protection and regulation of several nuclear processes. In patients' fibroblasts, muscle fructose 1,6-bisphosphatase shows no colocalization with mitochondria and nuclei leading to increased reactive oxygen species production and a disturbed mitochondrial network. In conclusion, the results of this study indicate that the variant in FBP2 disturbs cerebral energy metabolism and is associated with a novel remitting leukodystrophy.

Temporal profile of lymphocyte counts and relationship with infections with fingolimod therapy in paediatric patients with multiple sclerosis: Results from the PARADIGMS study.

BACKGROUND: Reduction in absolute lymphocyte count (ALC) is expected with fingolimod treatment. OBJECTIVE: To evaluate the effect of fingolimod 0.5 mg versus intramuscular interferon ß-1a (30 µg) on ALC and its relationship with infections in paediatric-onset multiple sclerosis (POMS) up to 4 years. METHODS: We assessed ALC at baseline, monthly till 3 months, and every 3 months (core phase) and with variable periodicity (extension phase) of Phase 3 PARADIGMS study (N = 215). Incidence rates (IRs) of infection-related adverse events (infAEs)/100 patient-years were analysed by on-study nadir ALC. RESULTS: With fingolimod, ALC rapidly reduced to 29.9%-34.4% of baseline values within 2 weeks and remained stable thereafter; no relevant changes observed with interferon. IRs of infAEs were 67.6 with fingolimod and 61.8 with interferon; IR ratios with respect to interferon, overall: 1.09, by nadir ALC 0.2-0.4 × 109/L: 1.13 and >0.4 × 109/L: 0.91. Three patients had a single episode of ALC <0.2 × 109/L (core phase). No opportunistic infections were observed and infection risk did not increase during the extension phase. CONCLUSION: In paediatric patients, the overall incidence of infections was comparable between fingolimod and interferon. No association was observed between nadir ALC and infections in POMS, although sample size may have been too small to rule an association.

CASPR2 autoimmunity in children expanding to mild encephalopathy with hypertension.

OBJECTIVE: To delineate autoimmune disease in association with contactin-associated protein 2 (CASPR2) antibodies in childhood, we reviewed the clinical phenotype of children with CASPR2 antibodies. METHODS: Retrospective assessment of patients recruited through laboratories specialized in autoimmune CNS disease. RESULTS: Ten children with serum CASPR2 antibodies were identified (age at manifestation 18 months to 17 years). Eight children with CASPR2 antibody titers from ≥1:160 to 1:5,120 had complex autoimmune diseases with an age-dependent clinical phenotype. Two children with structural epilepsy due to CNS malformations harbored nonspecific low-titer CASPR2 antibodies (serum titers 1:80). The clinical symptoms of the 8 children with high-titer CASPR2 antibodies were general weakness (8/8), sleep dysregulation (8/8), dysautonomia (8/8) encephalopathy (7/8), neuropathic pain (7/8), neuromyotonia (3/8), and flaccid paresis (3/8). Adolescents (3/8) showed pain, neuromyotonia, and encephalopathy, whereas younger children (5/8) displayed severe hypertension, encephalopathy, and hormonal dysfunction mimicking a systemic disease. No tumors were identified. Motor symptoms remitted with immunotherapy. Mild behavioral changes persisted in 1 child, and autism spectrum disorder was diagnosed during follow-up in a young boy. CONCLUSION: High-titer CASPR2 antibodies are associated with Morvan syndrome in children as young as 2 years. However, CASPR2 autoimmunity mimics systemic disease and hypertensive encephalopathy in children younger than 7 years. The outcome following immunotherapy was mostly favorable; long-term behavioral impairment may occur in younger children.

Serum neurofilament light chain is a useful biomarker in pediatric multiple sclerosis.

OBJECTIVE: To investigate serum neurofilament light chain (sNfL) as a potential biomarker for disease activity and treatment response in pediatric patients with multiple sclerosis (MS). METHODS: In this retrospective cohort study, sNfL levels were measured in a pediatric MS cohort (n = 55, follow-up 12-105 months) and in a non-neurologic pediatric control cohort (n = 301) using a high-sensitivity single-molecule array assay. Association of sNfL levels and treatment and clinical and MRI parameters were calculated. RESULTS: Untreated patients had higher sNfL levels than controls (median 19.0 vs 4.6 pg/mL; CI [4.732, 6.911]), p < 0.001). sNfL levels were significantly associated with MRI activity (+9.1% per contrast-enhancing lesion, CI [1.045, 1.138], p < 0.001; +0.6% per T2-weighted lesion, CI [1.001, 1.010], p = 0.015). Higher values were associated with a relapse <90 days ago (+51.1%; CI [1.184, 1.929], p < 0.001) and a higher Expanded Disability Status Scale score (CI [1.001, 1.240], p = 0.048). In patients treated with interferon beta-1a/b (n = 27), sNfL levels declined from 14.7 to 7.9 pg/mL after 6 ± 2 months (CI [0.339, 0.603], p < 0.001). Patients with insufficient control of clinical or MRI disease activity under treatment with interferon beta-1a/b or glatiramer acetate who switched to fingolimod (n = 18) showed a reduction of sNfL levels from 16.5 to 10.0 pg/mL 6 ± 2 months after switch (CI [0.481, 0.701], p < 0.001). CONCLUSIONS: sNfL is a useful biomarker for monitoring disease activity and treatment response in pediatric MS. It is most likely helpful to predict disease severity and to guide treatment decisions in patients with pediatric MS. This study provides Class III evidence that sNfL levels are associated with disease activity in pediatric MS.

Pregnancy outcomes in interferon-beta-exposed patients with multiple sclerosis: results from the European Interferon-beta Pregnancy Registry.

BACKGROUND: Family planning is an important consideration for women with multiple sclerosis (MS), who are often diagnosed during their reproductive years. Currently, limited data are available on pregnancy outcomes in patients exposed to interferon-beta (IFN-beta) before or during pregnancy. Here, we present the cumulative pregnancy exposure data and prevalence of pregnancy and infant outcomes in IFN-beta-exposed pregnant women with MS from the European IFN-beta Pregnancy Registry. METHODS: Using spontaneous and solicited reports, the registry collected data from 26 countries of the European Economic Area, consisting of information on women with MS identifying themselves to one of the Marketing Authorisation Holders (Bayer, Biogen, Merck KGaA, and Novartis) or healthcare professionals as pregnant and exposed to IFN-beta during pregnancy or within 1 month before conception. The outcomes collected by the registry included ectopic pregnancies, spontaneous abortions, elective terminations, live, and stillbirths with or without congenital anomalies. The prevalence of pregnancy outcomes was put in context with those reported in the general population. RESULTS: Between 2009 and 2017, the registry collected 948 pregnancy reports with a known pregnancy outcome. Overall, 82.0% (777/948) of pregnancies resulted in live birth without congenital anomaly. When comparing IFN-beta-exposed pregnancies with the general population, the prevalence of spontaneous abortions (10.7% vs. 10-21%) and congenital anomalies in live births (2.1% vs. 2.1-4.1%) were found to be within reported ranges. CONCLUSIONS: The data gathered from these pregnancy cases suggest no evidence that IFN-beta exposure before conception and/or during pregnancy adversely increases the rate of congenital anomalies or spontaneous abortions.

Delayed-Release Dimethyl Fumarate Safety and Efficacy in Pediatric Patients With Relapsing-Remitting Multiple Sclerosis.

Background: Pediatric multiple sclerosis (MS) is rare: only 1.5-5% of MS cases are diagnosed before 18 years of age, and data on disease-modifying therapies (DMTs) for pediatric MS are limited. The CONNECTED study assessed the long-term safety and efficacy of treatment with delayed-release dimethyl fumarate (DMF), an oral MS DMT, in pediatric patients with MS. Methods: CONNECTED is the 96-week extension to FOCUS, a 24-week phase 2 study of patients aged 13-17 years; participants received DMF 240 mg twice daily. Endpoints included (primary) incidence of adverse events (AEs), serious AEs, and DMF discontinuations due to an AE, and (secondary) T2 hyperintense lesion incidence by magnetic resonance imaging and annualized relapse rate (ARR). Results: Twenty participants [median (range) age, 17 (14-18) years; 65% female] who completed FOCUS enrolled into CONNECTED; 17 (85%) completed CONNECTED. Eighteen participants (90%) experienced AEs: the most frequent was flushing (25%). None experienced infections or fever related to low lymphocyte counts. Three participants experienced four serious AEs; none led to DMF discontinuation. Twelve of 17 participants (71%) had no new/newly enlarged T2 lesions from weeks 16-24, two (12%) had one, and one each (6%) had two, three, or five or more lesions [median (range), 0 (0-6)]. Over the full 120-week treatment period, ARR was 0.2, an 84.5% relative reduction (n = 20; 95% confidence interval: 66.8-92.8; p < 0.0001) vs. the year before DMF initiation. Conclusions: The long-term safety and efficacy observed in CONNECTED was consistent with adults, suggesting pediatric and adolescent patients with MS might benefit from DMF treatment.

Consistent control of disease activity with fingolimod versus IFN ß-1a in paediatric-onset multiple sclerosis: further insights from PARADIGMS.

BACKGROUND: In PARADIGMS, a double-blind phase III trial in 215 paediatric patients with multiple sclerosis (MS) (10 to <18 years), fingolimod administered for up to 2 years significantly reduced the annualised relapse rate (ARR) and rate of new/newly enlarged T2 (n/neT2) lesions compared with interferon (IFN) ß-1a. OBJECTIVES: To investigate (1) differences between treatment groups across subpopulations (treatment-naïve, younger/prepubertal patients); (2) disability progression. METHODS: ARRs at 10, 11 and 12 years were estimated based on predefined modelling extrapolations. Changes in Expanded Disability Status Scale (EDSS), and in 3 month (3M) and 6 month (6M) confirmed disability progression (CDP) were evaluated post hoc. RESULTS: In the treatment-naïve subpopulation, fingolimod reduced ARR and n/neT2 lesions by 85.8% and 53.4%, respectively versus INF ß-1a (both p<0.001), compared with 81.9% and 52.6% in the overall population. Model-based ARR reductions in younger patients (≤12 years) were 91.9%-94.6%. Twice as many IFN ß-1a-treated than fingolimod-treated patients had worse EDSS scores at study end (20.6% vs 10.5%, p=0.043). Risk reductions in 3M-CDP and 6M-CDP were 77.2% (p=0.007) and 80.2% (p=0.040), respectively. CONCLUSIONS: Fingolimod in paediatric MS was associated with consistent control of disease activity versus IFN ß-1a (including treatment-naïve and younger patients) and resulted in less disability progression for up to 2 years. TRIAL REGISTRATION NUMBER: NCT01892722.

Fatigue and depression predict health-related quality of life in patients with pediatric-onset multiple sclerosis.

BACKGROUND: Fatigue, depression and loss in health-related quality of life (HRQoL) have been reported to occur in a substantial amount of patients with pediatric-onset MS (POMS). This study aims to evaluate depression, fatigue and HRQoL and its relationship in a cohort of patients with POMS and matched healthy controls (HCs). METHODS: In a multicenter cross-sectional study, Beck Depression Inventory II, Depressionstest für Kinder, the Pediatric Quality of Life Inventory (PedsQL™) 4.0 Generic Core Scale and the PedsQL™ Multidimensional Fatique Scale were performed. RESULTS: In a cohort of 106 patients with POMS and 210 matched HCs, patients were significantly more often depressed (21.7% vs. 11.4%, p = 0.014) experienced greater fatigue (40.6% vs. 17.3%, p < 0.001) and a greater loss of HRQoL (43.4% vs. 15%, p < 0.001) than controls. Depression predicted 51.8% of variance of fatigue. Fatigue was also predicted by female gender. Loss of HRQoL was predicted by EDSS, depression and fatigue. Depression and fatigue together explained 67.7% of variance of HRQoL. CONCLUSION: Patients with POMS are at a significant increased risk for depression, fatigue and loss of HRQoL. Furthermore, fatigue and depression significantly predict reduced HRQoL in POMS, suggesting that testing for these symptoms and early therapy is of utmost importance in all patients with POMS.

Association of Obesity With Multiple Sclerosis Risk and Response to First-line Disease Modifying Drugs in Children.

Importance: Obesity reportedly increases the risk of pediatric multiple sclerosis (MS), but little is known about its association with disease course. Objective: To investigate the association of obesity with pediatric MS risk and with first-line therapy response among children with MS. Design, Setting, and Participants: This single-center retrospective study used the medical records and database at the Center for MS in Childhood and Adolescence, Göttingen, Germany. The study included 453 patients with relapsing-remitting pediatric MS and body mass index (BMI) measurement taken within 6 months of diagnosis. Onset of the disease occurred between April 28, 1990, and June 26, 2016, and the mean disease duration was 38.4 months. Data were collected from July 14, 2016, to December 18, 2017. Main Outcomes and Measures: Data on BMIs were stratified by sex and age using German BMI references and compared with the BMI data of 14 747 controls from a nationwide child health survey for odds ratio (OR) estimates. Baseline magnetic resonance imaging findings, intervals between first and second MS attacks, annualized relapse rates before and during treatment with interferon beta-1a or -1b and glatiramer acetate, frequency of second-line treatment, and Expanded Disability Status Scale (EDSS) scores were compared between nonoverweight (BMI≤90th percentile), overweight (BMI>90th-97th percentile), and obese (BMI>97th percentile) patients. Results: In total, 453 patients with pediatric MS were included, of whom 306 (67.5%) were female, and the mean (SD) age at diagnosis was 13.7 (2.7) years. At diagnosis, 126 patients (27.8%) were overweight or obese, with obesity associated with statistically significant twofold odds of MS in both sexes (girls OR, 2.19; 95% CI, 1.5-3.1; P < .001 vs boys OR, 2.14; 95% CI, 1.3-3.5; P = .003). Obese patients, compared with nonoverweight patients, had statistically significantly more relapses on first-line treatment with interferon beta and glatiramer acetate (ARR, 1.29 vs 0.72; P < .001) and a higher rate of second-line treatment (21 [56.8%] of 37 vs 48 [38.7%] of 124; P = .06). Baseline neuroimaging, interval between first and second MS attacks, pretreatment relapses, and EDSS progression scores were not correlated with BMI. Conclusions and Relevance: In this study, increased pediatric MS risk appeared to be associated with obesity, and obese patients did not respond well to first-line medications; altered pharmacokinetics appeared to be most likely factors in treatment response, suggesting that achieving healthy weight or adjusting the dose according to BMI could improve therapy response.

Homozygous NMNAT2 mutation in sisters with polyneuropathy and erythromelalgia.

We identified a homozygous missense mutation in the gene encoding NAD synthesizing enzyme NMNAT2 in two siblings with childhood onset polyneuropathy with erythromelalgia. No additional homozygotes for this rare allele, which leads to amino acid substitution T94M, were present among the unaffected relatives tested or in the 60,000 exomes of the ExAC database. For axons to survive, axonal NMNAT2 activity has to be maintained above a threshold level but the T94M mutation confers a partial loss of function both in the ability of NMNAT2 to support axon survival and in its enzymatic properties. Electrophysiological tests and histological analysis of sural nerve biopsies in the patients were consistent with loss of distal sensory and motor axons. Thus, it is likely that NMNAT2 mutation causes this pain and axon loss phenotype making this the first disorder associated with mutation of a key regulator of Wallerian-like axon degeneration in humans. This supports indications from numerous animal studies that the Wallerian degeneration pathway is important in human disease and raises important questions about which other human phenotypes could be linked to this gene.

Therapy of highly active pediatric multiple sclerosis.

OBJECTIVE: Study aims were to determine the frequency of highly active disease in pediatric multiple sclerosis (MS), the response to natalizumab (NTZ) and fingolimod (FTY) treatment, and the impact of current treatment modalities on the clinical course. METHODS: Retrospective single-center study in the German Center for MS in Childhood and Adolescence. RESULTS: Of 144 patients with first MS manifestation between 2011 and 2015, 41.6% fulfilled the criteria for highly active MS. In total, 55 patients treated with NTZ and 23 with FTY demonstrated a significant reduction in relapse rate (NTZ: 95.2%, FTY: 75%), new T2 lesions (NTZ: 97%, FTY: 81%), and contrast-enhancing lesions (NTZ: 97%, FTY: 93%). However, seven patients switched from NTZ to FTY experienced an increase in disease activity. Comparing pediatric MS patients treated in 2005 with those treated in 2015 showed a 46% reduction in relapse rate and a 44% reduction in mean Expanded Disability Status Scale (EDSS). CONCLUSION: The rate of highly active disease among pediatric MS patients is high; more than 40% in our cohort. Response to NTZ and FTY treatment is similar if not better than observed in adults. Current treatment modalities including earlier treatment initiation and the introduction of NTZ and FTY have significantly improved the clinical course of pediatric MS.