Expanding the Clinical Spectrum of DRP2-Associated Charcot-Marie-Tooth Disease

BACKGROUND AND OBJECTIVES

Germline truncating variants in the DRP2 gene (encoding dystrophin-related protein 2) cause the disruption of the periaxin-DRP2-dystroglycan complex and have been linked to Charcot-Marie-Tooth disease. However, the causality and the underlying phenotype of the genetic alterations are not clearly defined.

METHODS

This cross-sectional retrospective observational study includes 9 patients with Charcot-Marie-Tooth disease (CMT) with DRP2 germline variants evaluated at 6 centers throughout Spain.

RESULTS

We identified 7 Spanish families with 4 different DRP2 likely pathogenic germline variants. In agreement with an X-linked inheritance, men harboring hemizygous DRP2 variants presented with an intermediate form of CMT, whereas heterozygous women were asymptomatic. Symptom onset was variable (36.6 ± 16 years), with lower limb weakness and multimodal sensory loss producing a mild-to-moderate functional impairment. Nerve echography revealed an increase in the cross-sectional area of nerve roots and proximal nerves. Lower limb muscle magnetic resonance imaging confirmed the presence of a length-dependent fatty infiltration. Immunostaining in intradermal nerve fibers demonstrated the absence of DRP2 and electron microscopy revealed abnormal myelin thickness that was also detectable in the sural nerve sections.

DISCUSSION

Our findings support the causality of DRP2 pathogenic germline variants in CMT and further define the phenotype as a late-onset sensory and motor length-dependent neuropathy, with intermediate velocities and thickening of proximal nerve segments.

Description of clinical and genetic features of 122 patients included in the Spanish Pompe registry

Pompe disease is a rare genetic disorder with an estimated prevalence of 1:60.000. The two main phenotypes are Infantile Onset Pompe Disease (IOPD) and Late Onset Pompe Disease (LOPD). There is no published data from Spain regarding the existing number of cases, regional distribution, clinical features or, access and response to the treatment. We created a registry to collect all these data from patients with Pompe in Spain. Here, we report the data of the 122 patients registered including nine IOPD and 113 LOPD patients. There was a high variability in how the diagnosis was obtained and how the follow-up was performed among different centres. Seven IOPD patients were still alive being all treated with enzymatic replacement therapy (ERT) at last visit. Ninety four of the 113 LOPD patients had muscle weakness of which 81 were receiving ERT. We observed a progressive decline in the results of muscle function tests during follow-up. Overall, the Spanish Pompe Registry is a valuable resource for understanding the demographics, patient's journey and clinical characteristics of patients in Spain. Our data supports the development of agreed guidelines to ensure that the care provided to the patients is standardized across the country.

Association of Blood-Based DNA Methylation Markers With Late-Onset Alzheimer Disease: A Potential Diagnostic Approach

BACKGROUND AND OBJECTIVES

There is an urgent need to identify novel noninvasive biomarkers for Alzheimer disease (AD) diagnosis. Recent advances in blood-based measurements of phosphorylated tau (pTau) species are promising but still insufficient to address clinical needs. Epigenetics has been shown to be helpful to better understand AD pathogenesis. Epigenetic biomarkers have been successfully implemented in other medical disciplines, such as oncology. The objective of this study was to explore the diagnostic accuracy of a blood-based DNA methylation marker panel as a noninvasive tool to identify patients with late-onset Alzheimer compared with age-matched controls.

METHODS

A case-control study was performed. Blood DNA methylation levels at 46 cytosine-guanine sites (21 genes selected after a comprehensive literature search) were measured by bisulfite pyrosequencing in patients with "probable AD dementia" following National Institute on Aging and the Alzheimer's Association guidelines (2011) and age-matched and sex-matched controls recruited at Neurology Department-University Hospital of Navarre, Spain, selected by convenience sampling. Plasma pTau181 levels were determined by Simoa technology. Multivariable logistic regression analysis was performed to explore the optimal model to discriminate patients with AD from controls. Furthermore, we performed a stratified analysis by sex.

RESULTS

The final study cohort consisted of 80 patients with AD (age: median [interquartile range] 79 [11] years; 58.8% female) and 100 cognitively healthy controls (age 77 [10] years; 58% female). A panel including DNA methylation levels at NXN, ABCA7, and HOXA3 genes and plasma pTau181 significantly improved (area under the receiver operating characteristic curve 0.93, 95% CI 0.89-0.97) the diagnostic performance of a single pTau181-based model, adjusted for age, sex, and APOE ɛ4 genotype. The sensitivity and specificity of this panel were 83.30% and 90.00%, respectively. After sex-stratified analysis, HOXA3 DNA methylation levels showed consistent association with AD.

DISCUSSION

These results highlight the potential translational value of blood-based DNA methylation biomarkers for noninvasive diagnosis of AD.

REGISTRATION INFORMATION

Research Ethics Committee of the University Hospital of Navarre (PI17/02218).

Liquid Biopsy in Alzheimer's Disease Patients Reveals Epigenetic Changes in the PRLHR Gene

In recent years, new DNA methylation variants have been reported in genes biologically relevant to Alzheimer's disease (AD) in human brain tissue. However, this AD-specific epigenetic information remains brain-locked and unreachable during patients' lifetimes. In a previous methylome performed in the hippocampus of 26 AD patients and 12 controls, we found higher methylation levels in AD patients in the promoter region of PRLHR, a gene involved in energy balance regulation. Our aim was to further characterize PRLHR's role in AD and to evaluate if the liquid biopsy technique would provide life access to this brain information in a non-invasive way. First, we extended the methylation mapping of PRLHR and validated previous methylome results via bisulfite cloning sequencing. Next, we observed a positive correlation between PRLHR methylation levels and AD-related neuropathological changes and a decreased expression of PRLHR in AD hippocampus. Then, we managed to replicate the hippocampal methylation differences in plasma cfDNA from an additional cohort of 35 AD patients and 35 controls. The isolation of cfDNA from the plasma of AD patients may constitute a source of potential epigenetic biomarkers to aid AD clinical management.

Exploring the Disease-Associated Microglia State in Amyotrophic Lateral Sclerosis

BACKGROUND

Neuroinflammation, and specifically microglia, plays an important but not-yet well-understood role in the pathophysiology of amyotrophic lateral sclerosis (ALS), constituting a potential therapeutic target for the disease. Recent studies have described the involvement of different microglial transcriptional patterns throughout neurodegenerative processes, identifying a new state of microglia: disease-associated microglia (DAM). The aim of this study is to investigate expression patterns of microglial-related genes in ALS spinal cord.

METHODS

We analyzed mRNA expression levels via RT-qPCR of several microglia-related genes in their homeostatic and DAM state in postmortem tissue (anterior horn of the spinal cord) from 20 subjects with ALS-TDP43 and 19 controls donors from the Navarrabiomed Biobank.

RESULTS

The expression levels of TREM2, MS4A, CD33, APOE and TYROBP were found to be elevated in the spinal cord from ALS subjects versus controls (p-value < 0.05). However, no statistically significant gene expression differences were observed for TMEM119, SPP1 and LPL.

CONCLUSIONS

This study suggests that a DAM-mediated inflammatory response is present in ALS, and TREM2 plays a significant role in immune function of microglia. It also supports the role of C33 and MS4A in the physiopathology of ALS.

Profiling TREM2 expression in amyotrophic lateral sclerosis

BACKGROUND AND OBJECTIVES

There is growing evidence of the contribution of neuroinflammation, and in particular microglia, in the pathogenesis of amyotrophic lateral sclerosis (ALS). TREM2 gene plays a crucial role in shaping microglia in neurodegenerative conditions. To deepen the understanding of TREM2 in ALS and investigate the performance of TREM2 as a biomarker, we profiled TREM2 expression levels in spinal cord, cerebrospinal fluid and blood of patients with sporadic ALS. We also wanted to investigate whether the combined measurement of sTREM2 in fluids could improve the diagnostic yield of total and phosphorylated TDP-43 levels.

METHODS

We performed a case-control study to profile overall and transcript-specific TREM2 mRNA levels by RT-qPCR and protein expression levels by Western-blot in postmortem specimens of spinal cord from ALS patients and controls. In parallel, we measured soluble TREM2 (sTREM2) protein levels and full length and phosphorylated TDP-43 (tTDP-43 and pTDP-43) by ELISA in CSF and serum from ALS patients vs healthy controls. Patients were prospectively recruited from an ALS unit of a tertiary hospital and fulfilled El Escorial revised criteria. After bivariate analysis, a logistic regression model was developed to identify adjusted estimates of the association of sTREM2 levels in CSF and serum with ALS status.

RESULTS

Overall and transcript-specific TREM2 mRNA were upregulated in the spinal cord of ALS patients (n = 21) compared to controls (n = 19). Similar changes were observed in TREM2 protein levels (p < 0.01) in spinal cord of ALS patients vs healthy controls. We also detected significantly higher sTREM2 levels in CSF (p-value < 0.01) of ALS patients (n = 46) vs controls (n = 46) and serum (p-value < 0.001) of ALS patients (n = 100) vs controls (n = 100). In a logistic regression model, both CSF and serum sTREM2 remained independently associated with ALS status with OR = 3.41 (CI 95 %=1.34-8.66) (p-value < 0.05) and OR = 3.38 (CI 95 %: 1.86-6.16) (p-value < 0.001), respectively. We also observed that pTDP-43 levels in CSF is an independent predictor of ALS (p-value < 0.05).

CONCLUSIONS

Our results support the role of TREM2 in ALS pathophysiology and demonstrates that the three TREM2 transcripts are deregulated in ALS in postmortem human specimens of spinal cord. We hypothesise about the possible influence of systemic-peripheral inflammation in the disease. Finally, we conclude that pTDP-43 levels in CSF could be a biomarker of ALS, and sTREM2 measurement in CSF and blood emerge as potential non-invasive biomarker in ALS.

A novel phenotype of AChR-deficiency syndrome with predominant facial and distal weakness resulting from the inclusion of an evolutionary alternatively-spliced exon in CHRNA1

Primary acetylcholine receptor deficiency is the most common subtype of congenital myasthenic syndrome, resulting in reduced amount of acetylcholine receptors expressed at the muscle endplate and impaired neuromuscular transmission. AChR deficiency is caused mainly by pathogenic variants in the ε-subunit of the acetylcholine receptor encoded by CHRNE, although pathogenic variants in other subunits are also seen. We report the clinical and molecular features of 13 patients from nine unrelated kinships with acetylcholine receptor deficiency harbouring the CHRNA1 variant NM_001039523.3:c.257G>A (p.Arg86His) in homozygosity or compound heterozygosity. This variant results in the inclusion of an alternatively-spliced evolutionary exon (P3A) that causes expression of a non-functional acetylcholine receptor α-subunit. We compare the clinical findings of this group to the other cases of acetylcholine receptor deficiency within our cohort. We report differences in phenotype, highlighting a predominant pattern of facial and distal weakness in adulthood, predominantly in the upper limbs, which is unusual for acetylcholine receptor deficiency syndromes, and more in keeping with slow-channel syndrome or distal myopathy. Finally, we stress the importance of including alternative exons in variant analysis to increase the probability of achieving a molecular diagnosis.

Neuroinflammation-Related Proteins NOD2 and Spp1 Are Abnormally Upregulated in Amyotrophic Lateral Sclerosis

BACKGROUND AND OBJECTIVES

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of unknown etiology and poorly understood pathophysiology. There is no specific biomarker either for diagnosis or prognosis. The aim of our study was to investigate differentially expressed proteins in the CSF and serum from patients with ALS to determine their role in the disease process and evaluate their utility as diagnostic or prognostic biomarkers.

METHODS

We performed mass spectrometry in the CSF from 3 patients with ALS and 3 healthy controls (HCs). The results were compared with motor cortex dysregulated transcripts obtained from 11patients with sporadic ALS and 8 HCs. Candidate proteins were tested using ELISA in the serum of 123 patients with ALS, 30 patients with Alzheimer disease (AD), 28 patients with frontotemporal dementia (FTD), and 102 HCs. Patients with ALS, AD, and FTD were prospectively recruited from January 2003 to December 2020. A group of age-matched HCs was randomly selected from the Sant Pau Initiative on Neurodegeneration cohort of the Sant Pau Memory Unit.

RESULTS

Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) and osteopontin (Spp1) were differentially expressed in the CSF and the motor cortex transcriptome of patients with ALS compared with that in HCs (p < 0.05). NOD2 and Spp1 levels were significantly higher in sera from patients with ALS than in HCs (p < 0.001). Receiver operating characteristic analysis showed an area under the curve of 0.63 for NOD2 and 0.81 for Spp1. NOD2 levels were significantly lower in patients with AD and FTD than in patients with ALS (p < 0.0001), but we found no significant differences in Spp1 levels between patients with ALS, AD (p = 0.51), and FTD (p = 0.42). We found a negative correlation between Spp1 levels and ALS functional rating scale (r = -0.24, p = 0.009).

DISCUSSION

Our discovery-based approach identified NOD2 as a novel biomarker in ALS and adds evidence to the contribution of Spp1 in the disease process. Both proteins are involved in innate immunity and autophagy and are increased in the serum from patients with ALS. Our data support a relevant role of neuroinflammation in the pathophysiology of the disease and may identify targets for disease-modifying treatments in ALS. Further longitudinal studies should investigate the diagnostic and prognostic value of NOD2 and Spp1 in clinical practice.

Drug-refractory myasthenia gravis: Clinical characteristics, treatments, and outcome

Objective

To describe the clinical characteristics and outcomes in patients with refractory myasthenia gravis (MG) and to determine the effectiveness and side effects of the drugs used for their treatment.

Methods

This observational retrospective cross‐sectional multicenter study was based on data from the Spanish MG Registry (NMD‐ES). Patients were considered refractory when their MG Foundation of America post‐interventional status (MGFA‐PIS) was unchanged or worse after corticosteroids and two or more other immunosuppressive agents. Clinical and immunologic characteristics of drug‐refractory patients, efficiency and toxicity of drugs used, and outcome (MGFA‐PIS) at end of follow‐up were studied.

Results

We included 990 patients from 15 hospitals. Eighty‐four patients (68 of 842 anti‐acetylcholine receptor [AChR], 5 of 26 anti‐muscle‐specific tyrosine kinase [MusK], 10 of 120 seronegative, and 1 of 2 double‐seropositive patients) were drug refractory. Drug‐refractory patients were more frequently women (p < 0.0001), younger at onset (p < 0.0001), and anti‐MuSK positive (p = 0.037). Moreover, they more frequently presented a generalized form of the disease, bulbar symptoms, and life‐threatening events (p < 0.0001; p = 0.018; and p = 0.002, respectively) than non‐drug‐refractory patients. Mean follow‐up was 9.8 years (SD 4.5). Twenty‐four (50%) refractory patients had side effects to one or more of the drugs. At the end of follow‐up, 42.9% of drug‐refractory patients (42.6% of anti‐AChR, 100% of anti‐MuSK, and 10% of seronegative patients) and 79.8% of non‐drug‐refractory patients (p < 0.0001) achieved remission or had minimal manifestations. Eighty percent of drug‐refractory‐seronegative patients did not respond to any drug tested.

Interpretation

In this study, 8.5% of MG patients were drug‐refractory. New more specific drugs are needed to treat drug‐refractory MG patients.

Clinical characteristics and outcomes of thymoma-associated myasthenia gravis

BACKGROUND AND PURPOSE

Prognosis of myasthenia gravis (MG) in patients with thymoma is not well established. Moreover, it is not clear whether thymoma recurrence or unresectable lesions entail a worse prognosis of MG.

METHODS

This multicenter study was based on data from a Spanish neurologist-driven MG registry. All patients were aged >18 years at onset and had anti-acetylcholine receptor antibodies. We compared the clinical data of thymomatous and nonthymomatous patients. Prognosis of patients with recurrent or nonresectable thymomas was assessed.

RESULTS

We included 964 patients from 15 hospitals; 148 (15.4%) had thymoma-associated MG. Median follow-up time was 4.6 years. At onset, thymoma-associated MG patients were younger (52.0 vs. 60.4 years, p < 0.001), had more generalized symptoms (odds ratio [OR]: 3.02, 95% confidence interval [CI]: 1.95-4.68, p < 0.001) and more severe clinical forms according to the Myasthenia Gravis Foundation of America (MGFA) scale (OR: 1.6, 95% CI: 1.15-2.21, p = 0.005). Disease severity based on MGFA postintervention status (MGFA-PIS) was higher in thymomatous patients at 1 year, 5 years, and the end of follow-up. Treatment refractoriness and mortality were also higher (OR: 2.28, 95% CI: 1.43-3.63, p = 0.001; hazard ratio: 2.46, 95% CI: 1.47-4.14, p = 0.001). Myasthenic symptoms worsened in 13 of 27 patients with recurrences, but differences in long-term severity were not significant. Fifteen thymomatous patients had nonresectable thymomas with worse MGFA-PIS and higher mortality at the end of follow-up.

CONCLUSIONS

Thymoma-associated MG patients had more severe myasthenic symptoms and worse prognosis. Thymoma recurrence was frequently associated with transient worsening of MG, but long-term prognosis did not differ from nonrecurrent thymoma. Patients with nonresectable thymoma tended to present severe forms of MG.

Clinical features and incidence trends of amyotrophic lateral sclerosis in Navarre, Spain, 2007-2018: a population-based study

Objective: Amyotrophic Lateral Sclerosis (ALS) is a heterogeneous neurodegenerative disorder with a median survival of 3 years. The aim of our study is to analyze the incidence, age-related phenotype and clinical onset, geographical distribution, survival and diagnostic delay of ALS in Navarre. Methods: This is a population-based observational retrospective study, including all residents of Navarre (a northern Spanish region) from 2007 to 2018, who were followed until 30th September 2020. Results: We observed a global incidence 2.47/100,000 person-years, with an upward trend throughout the study, with the highest being in the age group of 70-74 years old. Point prevalence in December 2018 was 6.64/100,000 inhabitants (95%CI: 4.52-8.45). Upper limbs weakness onset was the most frequent in young people (<60 years), and bulbar, lower limbs weakness, generalized and respiratory associated with older age. Bulbar phenotype is the most frequent in women and in 80+ group. The median survival from clinical onset was 27.7 months (95%CI: 24.0-31.4), higher in spinal phenotype and younger onset age, and the diagnosis delay was 10.0 months (95%CI: 8.9-11.2) from clinical onset. Conclusions: We have observed a trend of increasing incidence in older people where the bulbar phenotype and female predominance.

Novel PLEKHG5 mutations in a patient with childhood-onset lower motor neuron disease

The PLEKHG5 gene encodes a protein that activates the nuclear factor kappa B (NFκB) signaling pathway. Mutations in this gene have been associated with distal spinal muscular atrophy IV and intermediate axonal neuropathy C, both with an autosomal recessive mode of inheritance. Two families with low motor neuron disease (LMND) caused by mutations in PLEKHG5 have been reported to date. We present a third LMND family, the first nonconsanguineous, due to two not previously reported PLEKHG5 mutations. Our results confirm and extend previous findings linking PLEKHG5 mutations to lower motor neuron diseases.

Clinical and therapeutic features of myasthenia gravis in adults based on age at onset

OBJECTIVE

To describe the characteristics of patients with very-late-onset myasthenia gravis (MG).

METHODS

This observational cross-sectional multicenter study was based on information in the neurologist-driven Spanish Registry of Neuromuscular Diseases (NMD-ES). All patients were >18 years of age at onset of MG and onset occurred between 2000 and 2016 in all cases. Patients were classified into 3 age subgroups: early-onset MG (age at onset <50 years), late-onset MG (onset ≥50 and <65 years), and very-late-onset MG (onset ≥65 years). Demographic, immunologic, clinical, and therapeutic data were reviewed.

RESULTS

A total of 939 patients from 15 hospitals were included: 288 (30.7%) had early-onset MG, 227 (24.2%) late-onset MG, and 424 (45.2%) very-late-onset MG. The mean follow-up was 9.1 years (SD 4.3). Patients with late onset and very late onset were more frequently men (p < 0.0001). Compared to the early-onset and late-onset groups, in the very-late-onset group, the presence of anti-acetylcholine receptor (anti-AChR) antibodies (p < 0.0001) was higher and fewer patients had thymoma (p < 0.0001). Late-onset MG and very-late-onset MG groups more frequently had ocular MG, both at onset (<0.0001) and at maximal worsening (p = 0.001). Although the very-late-onset group presented more life-threatening events (Myasthenia Gravis Foundation of America IVB and V) at onset (p = 0.002), they required fewer drugs (p < 0.0001) and were less frequently drug-refractory (p < 0.0001).

CONCLUSIONS

Patients with MG are primarily ≥65 years of age with anti-AChR antibodies and no thymoma. Although patients with very-late-onset MG may present life-threatening events at onset, they achieve a good outcome with fewer immunosuppressants when diagnosed and treated properly.

Epidemiological study and genetic characterization of inherited muscle diseases in a northern Spanish region

Background

Inherited muscle diseases are a group of rare heterogeneous muscle conditions with great impact on quality of life, for which variable prevalence has previously been reported, probably due to case selection bias. The aim of this study is to estimate the overall and selective prevalence rates of inherited muscle diseases in a northern Spanish region and to describe their demographic and genetic features. Retrospective identification of patients with inherited muscle diseases between 2000 and 2015 from multiple data sources. Demographic and molecular data were registered.

Results

On January 1, 2016, the overall prevalence of inherited muscle diseases was 59.00/ 100,000 inhabitants (CI 95%; 53.35–65.26). Prevalence was significantly greater in men (67.33/100,000) in comparison to women (50.80/100,000) (p = 0.006). The highest value was seen in the age range between 45 and 54 (91.32/100,000) years. Myotonic dystrophy type 1 was the most common condition (35.90/100,000), followed by facioscapulohumeral muscular dystrophy (5.15/100,000) and limb-girdle muscular dystrophy type 2A (2.5/100,000).

Conclusions

Prevalence of inherited muscle diseases in Navarre is high in comparison with the data reported for other geographical regions. Standard procedures and analyses of multiple data sources are needed for epidemiological studies of this heterogeneous group of diseases.

Parkinsonism and spastic paraplegia type 7: Expanding the spectrum of mitochondrial Parkinsonism

BACKGROUND

Pathogenic variants in the spastic paraplegia type 7 gene cause a complicated hereditary spastic paraplegia phenotype associated with classical features of mitochondrial diseases, including ataxia, progressive external ophthalmoplegia, and deletions of mitochondrial DNA.

OBJECTIVES

To better characterize spastic paraplegia type 7 disease with a clinical, genetic, and functional analysis of a Spanish cohort of spastic paraplegia type 7 patients.

METHODS

Genetic analysis was performed in patients suspecting hereditary spastic paraplegia and in 1 patient with parkinsonism and Pisa syndrome, through next-generation sequencing, whole-exome sequencing, targeted Sanger sequencing, and multiplex ligation-dependent probe analysis, and blood mitochondrial DNA levels determined by quantitative polymerase chain reaction.

RESULTS

Thirty-five patients were found to carry homozygous or compound heterozygous pathogenic variants in the spastic paraplegia type 7 gene. Mean age at onset was 40 years (range, 12-63); 63% of spastic paraplegia type 7 patients were male, and three-quarters of all patients had at least one allele with the c.1529C>T (p.Ala510Val) mutation. Eighty percent of the cohort showed a complicated phenotype, combining ataxia and progressive external ophthalmoplegia (65% and 26%, respectively). Parkinsonism was observed in 21% of cases. Analysis of blood mitochondrial DNA indicated that both patients and carriers of spastic paraplegia type 7 pathogenic variants had markedly lower levels of mitochondrial DNA than control subjects (228 per haploid nuclear DNA vs. 176 vs. 573, respectively; P < 0.001).

CONCLUSIONS

Parkinsonism is a frequent finding in spastic paraplegia type 7 patients. Spastic paraplegia type 7 pathogenic variants impair mitochondrial DNA homeostasis irrespective of the number of mutant alleles, type of variant, and patient or carrier status. Thus, spastic paraplegia type 7 supports mitochondrial DNA maintenance, and variants in the gene may cause parkinsonism owing to mitochondrial DNA abnormalities. Moreover, mitochondrial DNA blood analysis could be a useful biomarker to detect at risk families. © 2019 International Parkinson and Movement Disorder Society.

DNA methylation signature of human hippocampus in Alzheimer's disease is linked to neurogenesis

Background

Drawing the epigenome landscape of Alzheimer’s disease (AD) still remains a challenge. To characterize the epigenetic molecular basis of the human hippocampus in AD, we profiled genome-wide DNA methylation levels in hippocampal samples from a cohort of pure AD patients and controls by using the Illumina 450K methylation arrays.

Results

Up to 118 AD-related differentially methylated positions (DMPs) were identified in the AD hippocampus, and extended mapping of specific regions was obtained by bisulfite cloning sequencing. AD-related DMPs were significantly correlated with phosphorylated tau burden. Functional analysis highlighted that AD-related DMPs were enriched in poised promoters that were not generally maintained in committed neural progenitor cells, as shown by ChiP-qPCR experiments. Interestingly, AD-related DMPs preferentially involved neurodevelopmental and neurogenesis-related genes. Finally, InterPro ontology analysis revealed enrichment in homeobox-containing transcription factors in the set of AD-related DMPs.

Conclusions

These results suggest that altered DNA methylation in the AD hippocampus occurs at specific regulatory regions crucial for neural differentiation supporting the notion that adult hippocampal neurogenesis may play a role in AD through epigenetic mechanisms.

Graphical abstract

Electronic supplementary material

The online version of this article (10.1186/s13148-019-0672-7) contains supplementary material, which is available to authorized users.

Evaluation of Chitotriosidase and CC-Chemokine Ligand 18 as Biomarkers of Microglia Activation in Amyotrophic Lateral Sclerosis

Background: The development of biomarkers for use in diagnosing, monitoring disease progression and analyzing therapeutic trials response in amyotrophic lateral sclerosis (ALS) is essential. Objective: The aim of this study was to identify inflammatory factors in plasma or cerebrospinal fluid (CSF) from patients with ALS with particular attention to specific markers of microglia activation as chitotriosidase (ChT) and chemokine (C-C motif) ligand 18 (CCL18) to determine its potential as ALS biomarkers. Methods: We studied CSF and plasma samples from 32 patients and 42 healthy controls. We assayed the ChT activity by a spectrofluorometric method and protein levels of other inflammatory ­biomarkers (tumor necrosis factor [TNF]-alpha, interleukin [IL]-6 and CCL18) by enzyme-linked immunosorbent assay. CHIT1 gene polymorphism in exon 10 (c.1049_1072dup24) encoding inactive ChT enzyme was genotyped in all subjects. Results: ChT activity and TNF-alpha protein levels were significantly higher in CSF of ALS patients, but we found no correlation with the severity and progression of the disease. Nevertheless, we did not found any differences in CCL18 or IL-6 protein levels between both groups in CSF or plasma. In our sample, only 3% of subjects were homozygous carriers for the CHIT1 exon 10 duplication associated with defective enzyme. Conclusions: High ChT activity in CSF of patients with ALS may reflect microglia activation and could be a potential biomarker of the disease. We did not find any significant difference regarding CCL-18, another specific marker of microglia activation that is related with M2-like microglia phenotype. Deepening the understanding of the activation state of microglia (M1 and M2) may contribute to the knowledge about the specific role of neuroinflammation in ALS and future therapeutic strategies.

Liquid biopsy: a new source of candidate biomarkers in amyotrophic lateral sclerosis

Noninvasive tests to diagnose and monitor the progression of neurodegenerative disorders have been a challenge for decades. The aim of this study was to explore the feasibility of applying liquid biopsy procedures to patients with a neurodegenerative disease such as amyotrophic lateral sclerosis (ALS). We isolated plasma cell‐free DNA (cfDNA) in 20 ALS patients and 20 controls and used cfDNA to identify a novel differentially methylated mark in RHBDF2 gene in ALS patients compared to controls. Our findings support the notion that liquid biopsy may be applied to living patients as a source of potential epigenetic biomarkers for neurodegenerative disorders.

Brain Involvement in Myotonic Dystrophy Type 1: A Morphometric and Diffusion Tensor Imaging Study with Neuropsychological Correlation

Objective

Myotonic dystrophy type 1 (DM1), the most prevalent inherited neuromuscular disease in adults, is a genetic multisystem disorder with a well-established but not well-characterized cerebral involvement. The aim of this study was to evaluate the presence of white matter and gray matter abnormalities in DM1 patients and to investigate their relationship with neurocognitive dysfunction.

Methods

A total of 42 DM1 patients and 42 healthy controls were included in the study. Clinical, cognitive, and magnetic resonance imaging evaluations, including the use of structural and diffusion tensor imaging (DTI) techniques, were performed. White matter lesion (WML) load, volumetric analysis, and diffusivity changes were assessed and correlated with clinical and neuropsychological test findings.

Results

WMLs were significantly more frequent in DM1 patients (p < .001), and anterior temporal lobe lesions were only found in the patient group. Global and regional cortical volume loss and corpus callosum atrophy were found. Diffuse white matter DTI abnormalities, including fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity were observed with sparing of the internal capsule. Subcortical structures showed volume loss and increased median diffusivity. Neuropsychological evaluation showed significant impairment in several cognitive functions, but only visuospatial impairment was correlated with white matter abnormalities and cortical atrophy. Daytime sleepiness was associated with WML and ventral diencephalon and pallidum volume loss.

Conclusion

DM1 produces a widespread involvement of white matter and gray matter, including cortical and subcortical structures. These structural abnormalities are involved in the progressive neuropsychological functional impairment in these patients.

Myasthenia gravis: sleep quality, quality of life, and disease severity

INTRODUCTION

There is much research on quality of life in myasthenia gravis (MG), and its relationship to disease severity is well-established. However, evidence regarding sleep disturbance in MG is inconclusive.

METHODS

To evaluate sleep and quality of life among clinically stable MG patients, 54 subjects were investigated by means of the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and 15-Item-Quality-Of-Life Instrument for MG (MG-QOL15).

RESULTS

A pathological PSQI score, which was observed in 59% of patients, was increased in subjects with active disease compared with patients in clinical remission [odds ratio = 4.3; confidence interval 95% (1.0-17.6); P = 0.04]. We found a relationship between PSQI and MG-QOL15 scores in patients with clinically active disease (r = 0.62; P < 0.001).

CONCLUSIONS

Our study highlights the high prevalence of sleep disturbance among MG patients. Disease severity may be considered to be a MG-specific risk factor for patient-reported sleep disturbance. The MG-QOL15 and PSQI should be used to estimate the impact of the disease on sleep and quality of life.

Analysis of the C9orf72 gene in patients with amyotrophic lateral sclerosis in Spain and different populations worldwide

A hexanucleotide repeat expansion in chromosome 9 open reading frame 72 (C9orf72) can cause amyotrophic lateral sclerosis (ALS) and/or frontotemporal dementia (FTD). We assessed its frequency in 781 sporadic ALS (sALS) and 155 familial ALS (fALS) cases, and in 248 Spanish controls. We tested the presence of the reported founder haplotype among mutation carriers and in 171 Ceph Europeans from Utah (CEU), 170 Yoruba Africans, 81 Han Chinese, and 85 Japanese subjects. The C9orf72 expansion was present in 27.1% of fALS and 3.2% of sALS. Mutation carriers showed lower age at onset (P = 0.04), shorter survival (P = 0.02), greater co-occurrence of FTD (P = 8.2 × 10(-5)), and more family history of ALS (P = 1.4 × 10(-20)), than noncarriers. No association between alleles within the normal range and the risk of ALS was found (P = 0.12). All 61 of the mutation carriers were tested and a patient carrying 28 hexanucleotide repeats presented with the founder haplotype. This haplotype was found in 5.6% Yoruba Africans, 8.9% CEU, 3.9% Japanese, and 1.6% Han Chinese chromosomes.

Clinical and myopathological evaluation of early- and late-onset subtypes of myofibrillar myopathy

Myofibrillar myopathies (MFM) are a group of disorders associated with mutations in DES, CRYAB, MYOT, ZASP, FLNC, or BAG3 genes and characterized by disintegration of myofibrils and accumulation of degradation products into intracellular inclusions. We retrospectively evaluated 53 MFM patients from 35 Spanish families. Studies included neurologic exam, muscle imaging, light and electron microscopic analysis of muscle biopsy, respiratory function testing and cardiologic work-up. Search for pathogenic mutations was accomplished by sequencing of coding regions of the six genes known to cause MFM. Mutations in MYOT were the predominant cause of MFM in Spain affecting 18 of 35 families, followed by DES in 11 and ZASP in 3; in 3 families the cause of MFM remains undetermined. Comparative analysis of DES, MYOT and ZASP associated phenotypes demonstrates substantial phenotypic distinctions that should be considered in studies of disease pathogenesis, for optimization of subtype-specific treatments and management, and directing molecular analysis.

[Emergencies in neuromuscular pathology]

Acute muscle weakness (AMW) is the predominant symptom of neuromuscular emergencies, especially if it affects the respiratory or oropharyngeal musculature . AMW is a multi-etiological syndrome, with different lesion levels in the motor unit. Within the broad group of neuromuscular diseases, those that most frequently provoke AMW and respiratory failure are Guillain-Barré syndrome (GBS) and myasthenia gravis (MG). GBS is the most frequent cause of acute flaccid paralysis; it can cause respiratory failure in a third of cases, making mechanical ventilation necessary. Accurate diagnosis of this syndrome enables immunomodulatory treatment to be started, which has been shown to modify the course of the disease. Besides, clinical evaluation of the patients and knowledge of the simple tests of neurophysiology and respiratory function will guide the decision on mechanical ventilation, avoiding emergency intubation. The most frequent emergency caused by MG is myasthenic crisis, defined by the deterioration in the bulbar function with acute respiratory insufficiency and risk of respiratory stoppage. This occurs in 15-20% of myasthenic patients and can be triggered by numerous factors. Besides early identification of the crisis, it is important to suppress the triggering factors and to provide measure of ventilatory support. Amongst the pharmacological measures, the most useful instruments at present are plasmapheresis and intravenous immunoglobulins; these treatments do not cancel the need for intensive vigilance and of checking for imminent signs of respiratory failure that will involve invasive or non-invasive ventilatory support.

[Stroke in the XXI century. Emergency care]

Cerebrovascular diseases have reached epidemic proportions worldwide. They are the major cause of mortality in developed countries, accounting for over one-quarter of worldwide documented deaths, and the leading cause of severe disability in adults. Given that Spain will become one of the countries most affected by population ageing, an increase in the incidence of these diseases is expected in coming years. Several studies have reported that public levels of awareness of stroke warning signs, symptoms and risk factors are relatively low. Information campaigns aimed at increasing these levels of awareness and considering stroke as a neurological emergency are needed. The stroke code is a system which allows rapid identification, notification, and transfer of stroke patients to the emergency units. Technological advances in stroke diagnosis, and the development of effective therapeutic measures, such as thrombolytics, require a coordinated multidisciplinary approach. Treating patients in Stroke Units is the most effective and efficient approach in acute ischemic or hemorrhagic stroke management. In coming years research advances will provide new and better strategies in acute stroke treatment.

Serum chitotriosidase activity is increased in subjects with atherosclerosis disease

OBJECTIVE

This study was undertaken to analyze the relation between serum activity of chitotriosidase enzyme, a protein synthesized exclusively by activated macrophages, and atherosclerotic lesion extent in subjects with atherothrombotic stroke (ATS) and in subjects with ischemic heart disease (IHD).

METHODS AND RESULTS

We assayed the serum chitotriosidase activity and a common chitotriosidase gene polymorphism that causes deficiency in chitotriosidase activity in 3 Spanish populations, ATS (n=153), IHD (n=124), and control (n=148) subjects. Statistical differences were found in serum chitotriosidase activity between ATS (88.1+/-4.6 nmol/mL. h, P<0.0001) and IHD subjects (79.0+/-6.3, P=0.002) versus control group (70.9+/-5.2). These observed differences were not attributable to a distinct allelic or genotype distribution. The extension of the atherosclerotic lesion in carotids of ATS subjects was measured by duplex sonography. Chitotriosidase activities were 66.9+/-9.6, 88.7+/-8.3, and 107.7+/-11.8 for subjects with carotid stenosis <or=30%, 31% to 60%, and >60%, respectively. Statistical differences were observed between subjects with major and intermediate stenosis grade compared with subjects with minor stenosis, P=0.005 and P=0.016, respectively.

CONCLUSIONS

Serum chitotriosidase activity is significantly increased in individuals suffering from atherosclerosis disease and is related to the severity of the atherosclerotic lesion, suggesting a possible role as atherosclerotic extent marker.

[Acute symptomatic epilepsies]

OBJECTIVES

To review the differentiating characteristics of symptomatic acute epilepsies, epidemiology, aetiology and controversies over treatment, and describe our experience with symptomatic acute epilepsy in cerebrovascular disorders.

DEVELOPMENT AND CONCLUSIONS

The so-called symptomatic acute epilepsies show clearly differentiated characteristics with regard to true epileptic disorders: 1. A clearly identified causal association; 2. Generally tend not to recur; 3. Usually long-term anti-epileptic treatment is not necessary. Therefore the most suitable term for them is symptomatic acute seizures. They make up a large proportion of all newly-diagnosed epilepsies around 40%. The highest incidence occurs during the first year of life (probably because of the high incidence of seizures due to encephalopathies, metabolic disorders and infections) and in elderly patients (especially in relations to cerebrovascular disorders). The commonest causes are: cerebrovascular disorders, head injury, infections of the central nervous system, alcohol and drugs. The risk of subsequent epilepsy is increased in a subgroup of these patients, especially in cases with associated cerebrovascular disorders, head injuries and central nervous system infection. Long-term preventive treatment is rarely indicated in these patients.

[Acute transverse myelitis secondary to hepatitis B vaccination]

INTRODUCTION

Acute transverse myelitis is an inflammatory disorder. The pathogenesis is unclear, but the probable mechanism involves an autoimmune phenomenon. Possible causes included multiple sclerosis and parainfectious and postvaccinal events. Myelitis has rarely been reported secondary to vaccinations including hepatitis B. We present a case of acute myelitis, which seems secondary to the administration of the hepatitis B vaccine.

CLINICAL CASE

A 15-years-old female presented with progressive numbness of the right arm and leg, with right leg weakness. Symptom began one week after receiving the first dose of the hepatitis B vaccine. Spinal cord magnetic resonance (MR) revealed a diffuse increased signal extending from C6 to D2. Cerebral MR and cerebrospinal fluid were normal. She was treated with high doses of methylprednisolone with a complete recovery of neurological functional. Repeat medullar cord MR was normal. There was no relapse during a four years follow up.

CONCLUSIONS

Potential causal relationship between vaccination against hepatitis B and multiple sclerosis was brought to the attention and to public debate. However, no conclusive association could be made between vaccination and demyelination. In the clinical setting, the distinction between a first episode of multiple sclerosis or postvaccinal myelitis depends upon subsequent course.

[Thalamic hematomas: etiology, clinical findings and prognosis]

INTRODUCTION

The appearance of new neuroimaging techniques has permitted study of large series of thalamic hematomas, amongst which differences have been observed according to the size and arterial territory affected.

OBJECTIVE

To determine the existence or not of differences between thalamic hematomas, according to their arterial territory and size, with regard to the aetiology, clinical findings and short term prognosis.

PATIENTS AND METHODS

A retrospective study was made of 60 patients admitted to hospital with the diagnosis of thalamic hematoma (between January 1987 and July 1997) classified according to localization as: anterior, dorsal, posterolateral, posteromedial and global, and according to size as: large (> 20 mm), and small (< 20 mm) in which we analyzed the aetiology, clinical signs and prognosis up to discharge from hospital.

RESULTS

The commonest aetiology was found to be arterial hypertension (60%); with regard to the arterial territory involved we have observed different clinical and prognostic features but the number of patients in each group was too small to permit statistical analysis. Significant differences were shown with regard to the size of the hematoma: large hematomas more often extended to nearby structures, caused hydrocephalia, were associated with alteration in the level of consciousness, severe motor deficit, oculomotor changes, alteration in superior functions and hemianopsia, and had worse prognosis and increased mortality and dependence in everyday activity than small hematomas.

CONCLUSION

According to their size, thalamic hematomas show statistically significant clinical and prognostic differences.

[Miller-Fisher syndrome associated with toxoplasmosis]

We report on an immunocompetent patient who developed acquired toxoplasmosis and Miller-Fisher syndrome with central and peripheral neural involvement. We suggest the possible relationship between acquired toxoplasmosis and Miller-Fisher syndrome, even though we cannot exclude a mere coincidence. To our knowledge such an association has not been reported.

[Reading-induced epilepsy: three new cases]

INTRODUCTION

Primary epilepsy of reading is a rare syndrome in which patients present with mandibular myoclonia when reading texts. Seizures are also frequently provoked by other stimuli. Occasionally they may be followed by generalized tonic-clonic seizures.

CLINICAL CASES

We present the clinical features and electroencephalographs of three patients with epilepsy of reading, one of them also had seizures when playing chess and after doing arithmetic and the third after reading music. Treatment with valproic acid and clonazepam completely controlled the seizures in all three patients. In two cases we saw epileptiform activity on EEG whilst they were reading, although the basal EEG was normal.

CONCLUSIONS

We believe that epilepsy of reading is under-diagnosed and emphasize the importance of careful questioning of epileptic patients as to factors which may precipitate the seizures. In view of the social problems which may arise, early recognition of the syndrome is important for the patient.

[Epileptic seizures during sleep]

Introduction. Epileptic crises presenting exclusively during sleep are rare and pose more problems of diagnosis than do crises of diurnal presentation.

PATIENTS

We present the clinical and electroencephalographic data of 20 patients with exclusively sleep-induced epileptic crises, evaluating not only the type of crises and the diagnosis of the particular syndrome, but also the response to treatment and prognosis. The patients studied were over 17 years old, had only nocturnal crises and were followed up for a period of three years. An EEG done during sleep and cerebral CT scan were available in all cases and a cranial MR was available in two cases. Diagnosis was made using clinical data and the sleep EEG.

RESULTS

The majority (40%) had temporal lobe epilepsy. In two patients (10%) occipital paroxysms were found. In all cases both the neurological examination and the mental state were normal. The sleep EEG was pathological in 75% of the cases. Only three of the twenty patients had changes on the CT scan. Monotherapeutic antiepileptic treatment completely controlled the crises in 15 patients.

CONCLUSIONS

We wish to emphasize the usefulness and importance of the sleep EEG in defining the syndrome affecting these patients, the diagnostic difficulties in sleep epilepsy, the good response to antiepileptic treatment and the high incidence of recurrence if antiepileptic treatment is no longer given. In view of all these factors we believe that sleep epilepsy may be considered to be a syndrome of epilepsy.

[Neuropathic beriberi as a complication of surgery of morbid obesity]

We describe a women of 22 years of age who had had a vertical gastroplasty (as treatment for morbid obesity). She was admitted to hospital with a 4 week history of nausea and vomiting of food. Treatment with intravenous dextrose, without vitamin supplements was started. One week later she complained of diplopia, paresthesia and weakness of the limbs. All investigations proved to be normal. A deficiency state was suspected, probably Wernicke's encephalopathy, although no alterations were seen in her mental state. We started treatment with high doses of parenteral thiamine, other vitamins and a suitable diet. The treatment was followed by complete recovery. Few neurological complications have been described in association with vertical gastroplasty. The commonest are polyneuropathies. The probable deficiency origin of these is considered. We emphasise the importance of vitamin supplements following the surgical treatment of morbid obesity to avoid the development of deficiency states. Wernicke's encephalopathy is due to thiamine deficiency. It may be associated with any type of malnutrition, not only with chronic alcoholism. The full clinical triad which is diagnostic of this condition is only present in one third of the cases. When the condition is suspected on clinical grounds treatment should be started early to avoid the occurrence of irreversible secuelae.