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Abstract Background International patient registries are of particular importance for rare disorders, as they may contribute to overcome the lack of knowledge derived from low number of patients and limited awareness of these diseases, and help to learn more about their geographical or population-based specificities, which is relevant for research purposes and for promoting better standards of care and diagnosis. Our objective was to create and implement a European registry for patients with McArdle disease and other muscle glycogenoses (EUROMAC) and to disseminate the knowledge of these disorders. Results Teams from nine different countries (United Kingdom, Spain, Italy, France, Germany, Denmark, Greece, Turkey and USA) created a consortium that developed the first European registry dedicated to rare muscle glycogenoses. A work plan was implemented to design the database and platform that constitute the registry, by choosing clinical, genetics and molecular variables of interest, based on experience gained from previous national registries for similar metabolic disorders. Among dissemination activities, several teaching events were organized in different countries, especially those where the consortium considered the awareness of these diseases needs to be promoted among health professionals and patients. Conclusion EUROMAC represents a step forward in the knowledge of those disorders to which it is dedicated, and will have relevant clinical outcomes at the diagnostic, epidemiological, clinical and research level.

Transthyretin-related familial amyloid polyneuropathy (TTR-FAP) is caused by gain-of-toxic-function of TTR, which dissociates from its native tetramer form to a monomer form and aggregates in several tissues and organs. Mutations in the TTR gene lead to this amyloidogenic transformation and cause autosomal dominant disease. TTR-FAP typically causes sensorimotor FAP accompanied by autonomic involvement, but considerable phenotypic diversity is noted between different mutation types. In the event of clinical suspicion, TTR gene sequencing and pathologic confirmation are the recommended paths to follow. Significant improvement has been achieved in treating the disease over the past 20 years, starting with liver transplantation, followed by tetramer stabilizers and TTR-lowering therapies. Although there are still some uncertainties in diagnosing and treating TTR-FAP, recent advances are promising, especially in the field of treatment

OBJECTIVE: Oculopharyngodistal myopathy (OPDM) has been reported as a rare, adult-onset hereditary muscle disease. Patients show progressive oculopharyngeal and distal limb muscle involvement. As the genetic defect underlying OPDM is not known yet, the diagnosis currently rests upon clinical and histopathological features. This study aimed at investigating patterns of muscle alterations of OPDM patients by MRI and to search for possible clues to make differential diagnosis by using a non-invasive method. METHODS: Facial, upper and lower extremity muscles of 10 patients with OPDM, followed by the Neuromuscular Unit, Department of Neurology, Istanbul Faculty of Medicine, who had undergone detailed evaluation with manual muscle testing and who had different disease severity were evaluated with a 1.5-Tesla Philipps Achieve MR scanner using conventional T1 and T2 weighted axial images. The degree of muscle involvement on MRI was evaluated according to a modified 5-point scale. RESULTS: The mean age of onset was 20.1± 8.2 years (range 7- 39 years) and the mean disease duration was 14.5± 12.4 years (range 2-41 years). Seven patients showed dominantly distal (mild to severe/wheelchair bound), one patient dominantly proximal weakness and two patients had no weakness. The patients without weakness had normal imaging, but facial muscle MRI from one of them revealed mild involvement. Zygomatic and nasal muscles were the most severely and earliest involved muscles. MRI of all patients with muscle weakness showed a consistent selective muscle involvement pattern. Distal extremity muscles were more affected than proximal muscles. Earliest and most sever changes were found in semimembranous, biceps femoris and medial head of gastrocnemius and soleus muscle. Interestingly, sartorius, gracilis and semitendinous muscles and the lateral head of gastrocnemius were well-preserved in OPDM. CONCLUSION: Muscle MRI by showing selective involvement of exteremity muscle may be a non-invasive tool in the differential diagnosis of OPDM.

Stem cell application is one of the potential treatment methods for seizing the progression of amyotrophic lateral sclerosis (ALS) and for returning motor function if ever possible. Several different methods of stem cell application have been performed in experimental motor neuron disease models; the beneficial effects of these studies are controversial. There are few stem cell studies on ALS patients reported in the literature. The results of these studies either negative or have serious methodological problems. There is no sufficient laboratory or clinical data for designing a stem cell application trial in ALS patients for today.

Neuromuscular transmission failure in myasthenia gravis (MG) is most commonly elicited by autoantibodies (ab) to the acetylcholine receptor or the muscle-specific kinase, constituting AChR-MG and MuSK-MG. It is controversial whether these MG subtypes arise through different T helper (Th) 1, Th2 or Th17 polarized immune reactions and how these reactions are blunted by immunosuppression. To address these questions, plasma levels of cytokines related to various Th subtypes were determined in patients with AChR-MG, MuSK-MG and healthy controls (CON). Peripheral blood mononuclear cells (PBMC) were activated in vitro by anti-CD3, and cytokines were quantified in supernatants. In purified blood CD4+ T cells, RNA of various cytokines, Th subtype specific transcription factors and the co-stimulatory molecule, CD40L, were quantified by qRT-PCR. Plasma levels of Th1, Th2 and Th17 related cytokines were overall not significantly different between MG subtypes and CON. By contrast, in vitro stimulated PBMC from MuSK-MG but not AChR-MG patients showed significantly increased secretion of the Th1, Th17 and T follicular helper cell related cytokines, IFN-γ, IL-17A and IL-21. Stimulated expression of IL-4, IL-6, IL-10 and IL-13 was not significantly different. At the RNA level, expression of CD40L by CD4+ T cells was reduced in both AChR-MG and MuSK-MG patients while expression of Th subset related cytokines and transcription factors were normal. Immunosuppression treatment had two effects: First, it reduced levels of IL12p40 in the plasma of AChR-MG and MuSK-MG patients, leaving other cytokine levels unchanged; second, it reduced spontaneous secretion of IFN-γ and increased secretion of IL-6 and IL-10 by cultured PBMC from AChR-MG, but not MuSK-MG patients. We conclude that Th1 and Th17 immune reactions play a role in MuSK-MG. Immunosuppression attenuates the Th1 response in AChR-MG and MuSK-MG, but otherwise modulates immune responses in AChR-MG and MuSK-MG patients differentially.

A functional single nucleotide polymorphism (SNP) of the PTPN22 gene encoding a protein tyrosine phosphatase has been associated with autoimmune disorders including myasthenia gravis (MG). As the PTPN22 R620W polymorphism has a wide variation of allele frequencies among different populations, this polymorphism was investigated in MG in Turkey. An emphasis is put on MG subgroups according to autoantibody (Abs) production and presence of thymoma. DNA samples from 416 patients with clinically diagnosed generalized MG (231 with Abs to acetylcholine receptor, AChR-MG), 53 with Abs to muscle-specific kinase (MuSK-MG), 55 patients with no detectable Abs (SN-MG), 77 patients with thymoma (TAMG) and 293 healthy controls (HC) were genotyped for the SNP (PTPN22 R620W, C1858T, rs2476601). The PTPN22 T allele was increased in AChR-MG patients (odds ratio [OR]: 2.5, 95%CI: 1.2-5.1). The association was stronger in late disease-onset AChR (LOMG, OR: 3.1, 95%CI: 1.2-8.2). MuSK-MG, SN-MG and TAMG groups did not carry the variant allele more frequently than the HC. In contrast to findings in other autoimmune diseases, the distribution of the PTPN22 polymorphism in this population provides a susceptibility marker for AChR-MG. The strongest association is detected in patients with LOMG.

Abstract SNURPORTIN-1, encoded by SNUPN, plays a central role in the nuclear import of spliceosomal small nuclear ribonucleoproteins. However, its physiological function remains unexplored. In this study, we investigate 18 children from 15 unrelated families who present with atypical muscular dystrophy and neurological defects. Nine hypomorphic SNUPN biallelic variants, predominantly clustered in the last coding exon, are ascertained to segregate with the disease. We demonstrate that mutant SPN1 failed to oligomerize leading to cytoplasmic aggregation in patients’ primary fibroblasts and CRISPR/Cas9-mediated mutant cell lines. Additionally, mutant nuclei exhibit defective spliceosomal maturation and breakdown of Cajal bodies. Transcriptome analyses reveal splicing and mRNA expression dysregulation, particularly in sarcolemmal components, causing disruption of cytoskeletal organization in mutant cells and patient muscle tissues. Our findings establish SNUPN deficiency as the genetic etiology of a previously unrecognized subtype of muscular dystrophy and provide robust evidence of the role of SPN1 for muscle homeostasis.

The genome-wide presence of copy number variations (CNVs), which was shown to affect the expression and function of genes, has been recently suggested to confer risk for various human disorders, including Amyotrophic Lateral Sclerosis (ALS). We have performed a genome-wide CNV analysis using PennCNV tool and 733K GWAS data of 117 Turkish ALS patients and 109 matched healthy controls. Case-control association analyses have implicated the presence of both common (>5%) and rare (

Expansions of the polyglutamine (polyQ) domain (≥ 34) in Ataxin-2 (ATXN2) are the primary cause of spinocerebellar ataxia type 2 (SCA2). Recent studies reported that intermediate-length (27-33) expansions increase the risk of Amyotrophic Lateral Sclerosis (ALS) in 1-4% of cases in diverse populations. This study investigates the Turkish population with respect to ALS risk, genotyping 158 sporadic, 78 familial patients and 420 neurologically healthy controls. We re-assessed the effect of ATXN2 expansions and extended the analysis for the first time to cover the ATXN2 locus with 18 Single Nucleotide Polymorphisms (SNPs) and their haplotypes. In accordance with other studies, our results confirmed that 31-32 polyQ repeats in the ATXN2 gene are associated with risk of developing ALS in 1.7% of the Turkish ALS cohort (p=0.0172). Additionally, a significant association of a 136 kb haplotype block across the ATXN2 and SH2B3 genes was found in 19.4% of a subset of our ALS cohort and in 10.1% of the controls (p=0.0057, OR: 2.23). ATXN2 and SH2B3 encode proteins that both interact with growth receptor tyrosine kinases. Our novel observations suggest that genotyping of SNPs at this locus may be useful for the study of ALS risk in a high percentage of individuals and that ATXN2 and SH2B3 variants may interact in modulating the disease pathway.

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