The Canadian Collaborative Project on Genetic Susceptibility to Multiple Sclerosis cohort population structure and disease etiology

Background

Previous genetic and epidemiological studies have examined subpopulations from the Canadian Collaborative Project on Genetic Susceptibility to Multiple Sclerosis (CCPGSMS) patient cohort, but an encompassing analysis of the study population has not yet been carried out.

Objective

This study examines patterns of multiple sclerosis (MS) prevalence in 13,663 cohort members, including 4,821 patients with MS or suspected MS and 8,842 family members.

Methods

We grouped participants into epidemiologic subgroups based on age of MS onset, clinical stage at diagnosis, symptom type at disease onset, sex, proband status, disability as measured by the EDSS, and ancestry based on reported ethnicity.

Results

We observed a 2.7:1 MS prevalence ratio of women to men, though disease severity was greater for male patients. Variation in the age of disease onset between patients was only slightly associated with sex and strongly associated with disease type. Specific types of clinical symptoms at disease onset were associated with the prognosis. Regional residence did not correlate with disease onset, type, or severity.

Conclusion

Population trends, as presented here, are not explained by environmental factors alone, highlighting the need for a comprehensive genetic analysis to understand disease variance across families.

Erdheim-Chester disease of brain parenchyma without any systemic involvement: A case report and review of literature

Erdheim-Chester disease is a non-Langerhans cell histiocytosis syndrome characterised by histiocytic infiltration of different organs and systems in the body. Erdheim-Chester disease with isolated central nervous system (CNS) involvement causes diagnostic difficulties due to the absence of systemic findings and may result in misdiagnosis and inaccurate treatment choices. The case discussed in this report exemplifies how challenging it is to diagnose Erdheim-Chester disease with isolated CNS involvement. This case, which presented with progressive pyramidocerebellar syndrome, was clinically and radiologically resistant to all immunosuppressive and immunomodulatory treatments administered. The presence of false negative results in repeated histopathological investigations and the absence of evidence for systemic disease hindered the diagnosis and treatment work-up. In this study, we reviewed and discussed the prominent features of the presented case in light of the relevant literature.

HLA-B gene methylation and expression in Behçet's syndrome: a potential role of epigenetics in the pathogenesis

OBJECTIVES

The HLA-B51 locus has the strongest association with Behçet's syndrome (BS). The presence of a CpG island in the HLA-B gene led us to examine the role of epigenetic regulation in BS.

METHODS

HLA-B51 genotyping was performed via sequence-specific PCR in 15 index familial BS cases, 17 affected relatives, 26 unaffected relatives, 46 sporadic BS cases, and 41 healthy controls. HLA-B methylation level was determined using the Zymo OneStep qMethyl kit, and HLA-B51 mRNA level was assessed by quantitative real-time PCR in 14 index familial BS cases, 15 affected relatives, 15 unaffected relatives, 11 sporadic BS cases, and 10 healthy controls.

RESULTS

HLA-B51 carrier ratio was 13/15 in index familial cases, 13/17 in affected relatives, 22/26 in unaffected relatives, 8/25 in healthy controls, and 35/47 in sporadic BS cases. HLA-B51 expression level in HLA-B51+ BS cases was 2.2-fold higher than in their unaffected relatives (p=0.0149) and 1.3-fold higher than in healthy controls (p=0.0188), while sporadic BS cases had a 2.7-fold higher level than healthy controls (p=0.0487). HLA-B promoter methylation was significantly lower in HLA-B51+ familial BS cases than in unaffected relatives (0.4-fold, p=0.01), affected relatives (0.36-fold, p=0.0219), and healthy controls (0.34-fold, p=0.0371) and slightly lower in HLA-B51+ sporadic BS cases than in healthy controls (0.71-fold, p=0.2347). There was an inverse correlation between HLA-B promoter methylation and HLA-B51 expression in HLA-B51+ sporadic BS cases (p=0.0164).

CONCLUSIONS

This study indicates epigenetic involvement associated with the HLA-B51 locus in BS, both in familial and sporadic cases. Further studies with larger sample sizes are needed to confirm our results.

A Case of Coexistent Spinocerebellar Ataxia Type 2 and Primary Progressive Multiple Sclerosis-Coincidental or Associated?

Spinocerebellar ataxia type 2 (SCA2) is a dominantly inherited ataxia primarily characterised by progressive cerebellar syndrome, which is developed due to the expansion of the CAG trinucleotide repeat within the first exon of the ATXN2 gene. We report a rare case of a 41-year-old woman with coexistent genetically verified SCA2 and primary progressive multiple sclerosis (MS). Considering our case and a few others reported in the literature, as well as a possible genetic association between ATXN2 and MS susceptibility, we suggest that the coexistence of SCA and MS may not be coincidental, especially in patients with a progressive MS course.

Detection of a rare variant in PSTPIP1 through three generations in a family with an initial diagnosis of FMF/MKD-overlapping phenotype

OBJECTIVE

The presence of FMF cases without MEFV (MEFV innate immunity regulator, pyrin) pathogenic variants led us to search for other genes' involvement in the disease development. Here, we describe the presence of genetic heterogeneity in a three-generation family with an FMF/mevalonate kinase deficiency (MKD)-overlapping phenotype without MEFV/MVK (mevalonate kinase) pathogenic variants.

METHOD

Targeted sequencing revealed a rare, fully penetrant variant in PSTPIP1 (p.Arg228Cys, rs781341816). Computational stability analyses of PSTPIP1 protein were performed. PSTPIP1-pyrin protein interaction was examined by immunoprecipitation and immunoblotting in peripheral blood mononuclear cells (PBMCs) of patients and healthy controls. PBMCs were cultured, and inflammation was induced by LPS+ATP treatment, followed by protein level measurements of caspase-1, IL1ß, pyrin and PSTPIP1 in cell lysates and mature caspase-1 and mature IL1ß in supernatants.

RESULTS

The conserved, rare (GnomAD, 0.000028) PSTPIP1 p.Arg228Cys variant, previously reported in ClinVar as a variant with uncertain significance, showed complete penetrance in the family presenting an autosomal dominant pattern. Computational analyses showed a potentially destabilizing effect of the variant on PSTPIP1 protein. Accordingly, PSTPIP1-pyrin interaction was increased in patients harboring the variant, which resulted in elevated levels of mature caspase-1 and IL1ß in the inflammation-induced patient samples.

CONCLUSIONS

Unlike previously described cases with pyogenic arthritis, pyoderma gangrenosum, and acne (PAPA)-associated PSTPIP1 variants, our patients with the p.Arg228Cys variant presented with an FMF/MKD-overlapping phenotype. As additional data on the genetic heterogeneity in the variable clinical spectrum of autoinflammatory syndromes, we suggest that the p.Arg228Cys variant in PSTPIP1 is related to inflammation responses through strong PSTPIP1-pyrin interaction and pyrin inflammasome activation.

Comparison of multiple sclerosis patients with or without rebound activity after fingolimod cessation: Five-year clinical outcomes

BACKGROUND

Patients with multiple sclerosis (MS) who discontinue fingolimod might present with rebound activity. The reasons for the development of rebound have been identified, but there are limited data on the long-term clinical outcomes of these patients. This study aimed to compare the long-term outcomes of patients with MS with and without rebound activity after fingolimod discontinuation.

METHODS

A total of 31 patients who discontinued fingolimod for various reasons with a minimum follow-up of 5 years were included in the study. Of these, 10 were assigned to the rebound group and 21 to the non-rebound group. Clinical and demographic data and 5-year clinical outcomes of both groups were prospectively examined.

RESULTS

At fingolimod initiation, there were no significant differences in age, disease duration, and Expanded Disability Status Scale (EDSS) score. The annualized relapse rate (ARR) was significantly higher in the rebound group than in the non-rebound group before the fingolimod treatment (p = 0.005). In the rebound group, EDSS scores 2 months after rebound treatment and at the 5-year follow-up were not significantly different than before fingolimod initiation (p = 0.14 and p = 0.46, respectively). The last recorded EDSS was significantly higher in the non-rebound group than in the rebound group (3.6 ± 2.3 vs. 2.15 ± 1.4, p = 0.045). At the last follow-up, one patient was diagnosed with secondary progressive multiple sclerosis in the rebound group (10%), and 11 patients were in the non-rebound group (52.4%, p = 0.05).

CONCLUSION

When rebound activity is well-monitored and treated after fingolimod discontinuation, no overall EDSS change is expected in the long-term follow-up.

Prospective outcome analysis of multiple sclerosis cases reveals candidate prognostic cerebrospinal fluid markers

BACKGROUND

Predicting the long-term disability outcomes of multiple sclerosis (MS) cases is challenging.

OBJECTIVE

We prospectively analysed our previous MS cohort with initial cerebrospinal fluid (CSF) proteomics data to reveal disability markers after 8.2±2.2 years of follow-up.

METHODS

Patients with regular follow-up visits were assigned into two groups: those with an age-related MS severity (ARMSS) score ≥5 (unfavourable course group, N = 27) and ARMSS score <5 (favourable course group, N = 67). A machine learning-based algorithm was applied to reveal candidate poor prognosis-associated initial CSF proteins, which were measured in an independent MS cohort (verification group, N = 40) by ELISA. Additionally, the correlation of initial clinical and radiological parameters with long-term disability was analysed.

RESULTS

CSF alpha-2-macroglobulin (P = 0.0015), apo-A1 (P = 0.0016), and haptoglobin (P = 0.0003) protein levels, as well as cerebral lesion load (>9 lesions) on magnetic resonance imaging, gait disturbance (P = 0.04), and bladder/bowel symptoms (P = 0.01) were significantly higher in the unfavourable course group than in the favourable course group. Optic nerve involvement evident on initial magnetic resonance imaging (P = 0.002) and optic neuritis (P = 0.01) were more frequent in the favourable course group.

CONCLUSION

The herein identified initial CSF protein levels, in addition to the clinical and radiological parameters at disease onset, have predictive value for long-term disability in MS cases.

Genome-wide analysis of schizophrenia and multiple sclerosis identifies shared genomic loci with mixed direction of effects

Common genetic variants identified in genome-wide association studies (GWAS) show varying degrees of genetic pleiotropy across complex human disorders. Clinical studies of schizophrenia (SCZ) suggest that in addition to neuropsychiatric symptoms, patients with SCZ also show variable immune dysregulation. Epidemiological studies of multiple sclerosis (MS), an autoimmune, neurodegenerative disorder of the central nervous system, suggest that in addition to the manifestation of neuroinflammatory complications, patients with MS may also show co-occurring neuropsychiatric symptoms with disease progression. In this study, we analyzed the largest available GWAS datasets for SCZ (N = 161,405) and MS (N = 41,505) using Gaussian causal mixture modeling (MiXeR) and conditional/conjunctional false discovery rate (condFDR) frameworks to explore and quantify the shared genetic architecture of these two complex disorders at common variant level. Despite detecting only a negligible genetic correlation (rG = 0.057), we observe polygenic overlap between SCZ and MS, and a substantial genetic enrichment in SCZ conditional on associations with MS, and vice versa. By leveraging this cross-disorder enrichment, we identified 36 loci jointly associated with SCZ and MS at conjunctional FDR < 0.05 with mixed direction of effects. Follow-up functional analysis of the shared loci implicates candidate genes and biological processes involved in immune response and B-cell receptor signaling pathways. In conclusion, this study demonstrates the presence of polygenic overlap between SCZ and MS in the absence of a genetic correlation and provides new insights into the shared genetic architecture of these two disorders at the common variant level.

MYO1H is a novel candidate gene for autosomal dominant pure hereditary spastic paraplegia

In this study, we aimed to determine the genetic basis of a Turkish family related to hereditary spastic paraplegia (HSP) by exome sequencing. HSP is a progressive neurodegenerative disorder and displays genetic and clinical heterogeneity. The major symptoms are muscle weakness and spasticity, especially in the lower extremities. We studied seven affected and seven unaffected family members, as well as a clinically undetermined member, to identify the disease-causing gene. Exome sequencing was performed for four affected and two unaffected individuals. The variants were firstly filtered for HSP-associated genes, and we found a common variant in the ZFYVE27 gene, which has been previously implied for association with HSP. Due to the incompletely penetrant segregation pattern of the ZFYVE27 variant, revealed by Sanger sequencing, with the disease in this family, filtering was re-performed according to the mode of inheritance and allelic frequencies. The resulting 14 rare variants were further evaluated in terms of their cellular functions, and three candidate variants in ATAD3C, VPS16, and MYO1H genes were selected as possible causative variants, which were analyzed for their familial segregation. ATAD3C and VPS16 variants were eliminated due to incomplete penetrance. Eventually, the MYO1H variant NM_001101421.3:c.2972_2974del (p.Glu992del, rs372231088) was found as the possible disease-causing deletion for HSP in this family. This is the first study reporting the possible role of a MYO1H variant in HSP pathogenesis. Further studies on the cellular roles of Myo1h protein are needed to validate the causality of MYO1H gene at the onset of HSP.

Investigation of multiple sclerosis-related pathways through the integration of genomic and proteomic data

Background

Multiple sclerosis (MS) has a complex pathophysiology, variable clinical presentation, and unpredictable prognosis; understanding the underlying mechanisms requires combinatorial approaches that warrant the integration of diverse molecular omics data.

Methods

Here, we combined genomic and proteomic data of the same individuals among a Turkish MS patient group to search for biologically important networks. We previously identified differentially-expressed proteins by cerebrospinal fluid proteome analysis of 179 MS patients and 42 non-MS controls. Among this study group, 11 unrelated MS patients and 60 independent, healthy controls were subjected to whole-genome SNP genotyping, and genome-wide associations were assessed. Pathway enrichment analyses of MS-associated SNPs and differentially-expressed proteins were conducted using the functional enrichment tool, PANOGA.

Results

Nine shared pathways were detected between the genomic and proteomic datasets after merging and clustering the enriched pathways. Complement and coagulation cascade was the most significantly associated pathway (hsa04610, P = 6.96 × 10−30). Other pathways involved in neurological or immunological mechanisms included adherens junctions (hsa04520, P = 6.64 × 10−25), pathogenic Escherichia coli infection (hsa05130, P = 9.03 × 10−14), prion diseases (hsa05020, P = 5.13 × 10−13).

Conclusion

We conclude that integrating multiple datasets of the same patients helps reducing false negative and positive results of genome-wide SNP associations and highlights the most prominent cellular players among the complex pathophysiological mechanisms.

ICU shift related effects on sleep, fatigue and alertness levels

BACKGROUND

Shift work may lead to suboptimal sleep resulting in impaired alertness, and lowered performance levels, all of which can lead to medical errors.

AIMS

To examine fatigue, sleepiness and behavioural alertness prospectively in a tertiary level Australian intensive care unit (ICU).

METHODS

All full-time doctors providing 24-h resident cover on a 12-h day and 12-h night shift roster were invited to participate in this study. Data collected included Epworth Sleepiness Scale (ESS), sleep and awake history, Samn-Perelli Fatigue (SPF) Scale, Karolinska Sleepiness Scale (KSS) and iOS-based Psychomotor Vigilance Test (behavioural alertness). Data about medical emergency team (MET) shifts were collected separately as they were perceived to be busier shifts.

RESULTS

Twenty-nine ICU doctors participated in this study for a consecutive 6-week period. At baseline the median (interquartile range (IQR)) ESS was 5 (3-9). Day shift leads to an increase in fatigue and sleepiness (both P < 0.01). Night shift leads to worsening in fatigue, sleepiness and psychomotor vigilance (all P < 0.01). MET shifts had a lower psychomotor vigilance than non-MET shifts. The difference in the psychomotor vigilance was mostly due to the difference in recorded lapses and response time.

CONCLUSIONS

Shift work ICU doctors experience high levels of fatigue and sleepiness. Night shifts also lead to decreased vigilance. This is even more evident in doctors working MET shifts. These factors may lead to errors. Optimal rostering may reduce these effects and improve patient safety.

Correction to: Diagnostic utility of a targeted next-generation sequencing gene panel in the clinical suspicion of systemic autoinflammatory diseases: a multi-center study

The second affiliation of the corresponding author Eda Tahir Turanlı was incorrectly published as İstanbul Medeniyet University instead of Istanbul Technical University.

Alternatively spliced MEFV transcript lacking exon 2 and its protein isoform pyrin-2d implies an epigenetic regulation of the gene in inflammatory cell culture models

The function of gene body DNA methylation in alternative splicing, and its relation to disease pathogenesis is not fully elucidated. The gene for familial Mediterranean fever (MEFV) encodes the pyrin protein and contains a 998 bp CpG island, covering the second exon, which is differentially methylated in FMF patients compared to healthy controls. Our further observation of increased exon 2-spliced MEFV transcript in leukocytes of FMF patients provoked us to test the role of exon methylation in alternative splicing using inflammatory cell culture models. First, in vitro exon methylation triggered an increased level of exon 2 exclusion using a splicing cassette in a promyelocytic leukemia cell line (HL-60). HL-60 cells subjected to methylating and demethylating agents, as well as cells differentiated to neutrophil-like cells, exhibited different levels of spliced/unspliced transcripts. We observed increased levels of spliced transcripts in neutrophil-like (p = 0.0005), activated (p = 0.0034) and methylated cells (p < 0.0001), whereas decreased levels in demethylated cells (p = 0.0126) compared to control untreated HL-60 cells. We also showed that the protein isoform of pyrin lacking the exon 2 has an adverse subcellular localization in neutrophil-like cells. Therefore, it remains in the cytoplasm rather than the nucleus. This may point to an epigenetic involvement in an important inflammatory gene.

Group A streptococcal fasciitis

OBJECTIVE

To review the current understanding of group A streptococcal fasciitis; the different bacterial serotypes, the role of superantigens, antibiotic and other therapies, and transmission to house hold contacts and health care workers.

DATA SOURCES

Articles and published abstracts on the mechanisms and management of group A streptococcal fasciitis.

SUMMARY OF REVIEW

The development of streptococcal fasciitis depends on the inoculation of a susceptible individual (i.e. one who has not been previously exposed to that particular serotype or superantigen) with a virulent streptococcus that has the ability to produce superantigens. The superantigens produce an excessive stimulation of the immune system, with a subsequent outpouring of inflammatory cytokines causing the multiorgan failure that characterises both streptococcal necrotising fasciitis as well as streptococcal toxic shock syndrome. Effective management of streptococcal necrotising fasciitis requires an early diagnosis, appropriate surgery, administration of clindamycin (600 mg/70 kg i.v. 6-hourly), penicillin G (1.2 g/70 kg i.v. 2 to 4-hourly), and polyvalent immunoglobulin (0.2 - 0.4 g/kg/day i.v. for 3 - 5 days). Household and health workers in close contact with the patient need to be warned to present to medical care early if they develop any signs of an infection.

CONCLUSIONS

Necrotising fasciitis is a severe disorder which is commonly caused by group A streptococcus. Early diagnosis and effective management with surgery, antibiotics and polyvalent immunoglobulin will reduce mortality. Further studies concerning the risk of transmission of the organism to close contacts need to be performed.

Pressure-limited ventilation with permissive hypercapnia and minimum PEEP in saline-lavaged rabbits allows progressive improvement in oxygenation, but does not avoid ventilator-induced lung injury

OBJECTIVE

To determine whether pressure-limited intermittent mandatory ventilation with permissive hypercapnia and positive end-expiratory pressure (PEEP) titrated to arterial oxygen tension (PaO2) prevents or reduces acute lung injury, compared to conventional ventilation, in saline-lavaged rabbits.

DESIGN

Prospective randomised trial.

SETTING

University animal laboratory.

SUBJECTS

18 New Zealand White rabbits.

INTERVENTIONS

Following five sequential saline lung lavages, anaesthetised rabbits were randomly allocated in pairs to receive either of two ventilation protocols using intermittent mandatory ventilation. The study group had peak inspiratory pressure limited to 15 cm H2O and arterial partial pressure of carbon dioxide (PaCO2) was allowed to rise. The control group received 12 ml/kg tidal volume with rate adjusted for normocarbia. PEEP and fractional inspired oxygen (FIO2) were adjusted to maintain, PaO2 between 8 and 13.3 kPa (60 and 100 mm Hg) using a predetermined protocol. At 10 h or following death, lung lavage was repeated and lung histology evaluated.

MEASUREMENTS AND MAIN RESULTS

The mean increase in lavage cell counts and protein concentration and hyaline membrane scores were not significantly different between the groups. Oxygenation progressively improved more in the study group (p = 0.01 vs control for PaO2/FIO2 ratio and alveolar-arterial oxygen tension gradient (AaDO2)). PEEP was similar and the mean airway pressure higher in the control group, suggesting that this probably resulted from less ventilator-induced injury in the study group. Four deaths occurred in the control group (three due to pneumothorax and one to hypoxaemia) and none in the study group (p = 0.08).

CONCLUSIONS

This ventilatory protocol may have failed to prevent lung overdistension or it may have provided insufficient PEEP to prevent injury in this model; PEEP greater than the lower inflection point of the pressure-volume curve has been shown to prevent injury almost entirely.

A combined moist chamber and tray

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