Hereditary neuropathies (IPN) are a group of inherited peripheral neuropathies, which are characterized by distal muscle weakness, foot deformities and muscle atrophy. We have gathered a few families in whom the cause of the disease remained unknown – even after using a variety of methods like linkage analysis, targeted massively parallel sequencing of a gene panel and whole exome sequencing (WES). The aim of the project is to implement advanced analyses, clarify the causes of CMT disease in this group of patients with previously unexplained cause of hereditary neuropathy. We will use new possibilities and methods such as whole genome sequencing and RNA sequencing. Firstly, we will focus on four larger families, with clinically well documented inherited peripheral neuropathy and multiple affected members. Secondly, other families will also be included in the project (up to ten families).

Dědičné neuropatie, včetně nejčastější formy Charcot-Marie-Tooth (CMT), jsou skupinou onemocnění, pro které je charakteristické distální postižení končetin - svalová slabost a deformity nohou i rukou, svalové atrofie. V naší laboratoři je díky dlouholeté diagnostice této skupiny chorob pro celou ČR shromážděn velký soubor pacientů. Máme vybráno několik velkých rodin (minimálně 4), u kterých příčina onemocnění doposud není známa, a to i po provedení vyšetření nejčastějších genových poruch spojených s CMT, genového mapovaní na SNP čipech, nejnovější metody masivně paralelního sekvenování vyšetřením panelů všech genů, které jsou v současnosti spojovány s CMT a celoexomového sekvenování. Cílem projektu je provedení dalších moderních analýz v těchto rodinách, a tím objasnění příčiny dědičné neuropatie. Využijeme zcela nové možnosti a metody a to celogenomové sekvenování a transkriptomové sekvenování. V první fázi se zaměříme na objasnění příčiny u čtyř velkých rodin, ve druhé fázi budou do projektu zahrnuty i další rodiny (celkem až 10 rodin).

• MeSH
• hereditární motorické a senzitivní neuropatie diagnóza   genetika   MeSH
• lidé MeSH
• sekvenční analýza RNA metody   MeSH
• sekvenování celého genomu metody   MeSH
• sekvenování transkriptomu MeSH
• vzácné nemoci diagnóza   genetika   MeSH
• Check Tag
• lidé MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• genetika, lékařská genetika
• neurologie
• NLK Publikační typ
• závěrečné zprávy o řešení grantu AZV MZ ČR

The association of GNB4 with Charcot-Marie-Tooth (CMT) has recently been described in a publication by Soong et al. (Soong, et al., 2013). Here we present a patient with CMT in whom whole exome sequencing identified the mutation p.Lys57Glu in the GNB4 gene (NM_021629.3:c.169A>G). The patient, now 41 years old, is a sporadic case in the family. At the age of 35 he presented with severe disability (CMT neuropathy score 29), profound muscle atrophies, pes cavus and scoliosis. Previously, the patient was tested for PMP22 duplications/deletions and later also with 64 CMT gene panel, with no causal variant found. Subsequently, whole exome sequencing was performed. The p.Lys57Glu in the GNB4 gene was identified as the most probable causal variant, the mutation is not present in the patient's parents, neither in his unaffected sister, therefore we assume that the mutation arose de novo. Taken together, these findings support the causal and pathogenic character of the variant. Our report provides important evidence that GNB4 should become an established CMT gene and our findings confirm the original publication by Soong et al. (2013).

• MeSH
• Charcotova-Marieova-Toothova nemoc genetika   patologie   patofyziologie   MeSH
• dospělí MeSH
• lidé MeSH
• mutace MeSH
• proteiny vázající GTP - beta-podjednotky genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Geografické názvy
• Česká republika MeSH

BACKGROUND: Charcot-Marie-Tooth disease type 1A (CMT1A) is the most common inherited neuropathy, a debilitating disease without known cure. Among patients with CMT1A, disease manifestation, progression and severity are strikingly variable, which poses major challenges for the development of new therapies. Hence, there is a strong need for sensitive outcome measures such as disease and progression biomarkers, which would add powerful tools to monitor therapeutic effects in CMT1A. METHODS: We established a pan-European and American consortium comprising nine clinical centres including 311 patients with CMT1A in total. From all patients, the CMT neuropathy score and secondary outcome measures were obtained and a skin biopsy collected. In order to assess and validate disease severity and progression biomarkers, we performed qPCR on a set of 16 animal model-derived potential biomarkers in skin biopsy mRNA extracts. RESULTS: In 266 patients with CMT1A, a cluster of eight cutaneous transcripts differentiates disease severity with a sensitivity and specificity of 90% and 76.1%, respectively. In an additional cohort of 45 patients with CMT1A, from whom a second skin biopsy was taken after 2-3 years, the cutaneous mRNA expression of GSTT2, CTSA, PPARG, CDA, ENPP1 and NRG1-Iis changing over time and correlates with disease progression. CONCLUSIONS: In summary, we provide evidence that cutaneous transcripts in patients with CMT1A serve as disease severity and progression biomarkers and, if implemented into clinical trials, they could markedly accelerate the development of a therapy for CMT1A.

• MeSH
• biopsie MeSH
• Charcotova-Marieova-Toothova nemoc krev   genetika   terapie   MeSH
• dospělí MeSH
• fosfodiesterasy genetika   MeSH
• genetická transkripce genetika   MeSH
• genetické markery genetika   MeSH
• glutathiontransferasa genetika   MeSH
• glykoproteiny genetika   MeSH
• kathepsin A genetika   MeSH
• kůže patologie   MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• lidé středního věku MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• neuregulin-1 genetika   MeSH
• PPAR gama genetika   MeSH
• prognóza MeSH
• progrese nemoci * MeSH
• pyrofosfatasy genetika   MeSH
• senioři MeSH
• výsledek terapie * MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Although mutations in more than 90 genes are known to cause CMT, the underlying genetic cause of CMT remains unknown in more than 50% of affected individuals. The discovery of additional genes that harbor CMT2-causing mutations increasingly depends on sharing sequence data on a global level. In this way-by combining data from seven countries on four continents-we were able to define mutations in ATP1A1, which encodes the alpha1 subunit of the Na+,K+-ATPase, as a cause of autosomal-dominant CMT2. Seven missense changes were identified that segregated within individual pedigrees: c.143T>G (p.Leu48Arg), c.1775T>C (p.Ile592Thr), c.1789G>A (p.Ala597Thr), c.1801_1802delinsTT (p.Asp601Phe), c.1798C>G (p.Pro600Ala), c.1798C>A (p.Pro600Thr), and c.2432A>C (p.Asp811Ala). Immunostaining peripheral nerve axons localized ATP1A1 to the axolemma of myelinated sensory and motor axons and to Schmidt-Lanterman incisures of myelin sheaths. Two-electrode voltage clamp measurements on Xenopus oocytes demonstrated significant reduction in Na+ current activity in some, but not all, ouabain-insensitive ATP1A1 mutants, suggesting a loss-of-function defect of the Na+,K+ pump. Five mutants fall into a remarkably narrow motif within the helical linker region that couples the nucleotide-binding and phosphorylation domains. These findings identify a CMT pathway and a potential target for therapy development in degenerative diseases of peripheral nerve axons.

• MeSH
• Charcotova-Marieova-Toothova nemoc genetika   MeSH
• dítě MeSH
• dominantní geny * MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mutace genetika   MeSH
• rodina MeSH
• rodokmen MeSH
• sekvence aminokyselin MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• sodíko-draslíková ATPasa chemie   genetika   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Birk Barel syndrome also known as KCNK9 imprinting syndrome is a rare developmental disorder associated with a loss-of-function variant in KCNK9, an imprinted gene with maternal expression on the 8th chromosome encoding the TASK3 (TWIK-related acidity inhibited K + -channel 3). Only two variants of KCNK9 have been associated with this condition before, both of them leading to the same amino-acid exchange p.Gly236Arg (Barel, 2008, Graham, 2016). We describe a case of a 17-year-old girl presenting with very similar phenotype and pure motor neuropathy with a novel variant c.710C > A: p.Ala237Asp (NM_001282534.1) in KCNK9 found by whole exome sequencing. Our case suggests that Birk Barel syndrome may not be caused only by variants leading to amino-acid exchange p.Gly236Arg but also by other missense variant in this gene and that peripheral motor neuropathy might be a feature of this syndrome.

• MeSH
• draslíkové kanály s dvoupórovou doménou genetika   MeSH
• genetická predispozice k nemoci * MeSH
• genomový imprinting genetika   MeSH
• kraniofaciální abnormality genetika   patologie   MeSH
• lidé MeSH
• mentální retardace genetika   patologie   MeSH
• missense mutace genetika   MeSH
• mladiství MeSH
• sekvence aminokyselin genetika   MeSH
• sekvenování exomu MeSH
• svalová hypotonie genetika   patologie   MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

BACKGROUND: We investigated the features of the genomic rearrangements in a cohort of 50 male individuals with proteolipid protein 1 (PLP1) copy number gain events who were ascertained with Pelizaeus-Merzbacher disease (PMD; MIM: 312080). We then compared our new data to previous structural variant mutagenesis studies involving the Xq22 region of the human genome. The aggregate data from 159 sequenced join-points (discontinuous sequences in the reference genome that are joined during the rearrangement process) were studied. Analysis of these data from 150 individuals enabled the spectrum and relative distribution of the underlying genomic mutational signatures to be delineated. METHODS: Genomic rearrangements in PMD individuals with PLP1 copy number gain events were investigated by high-density customized array or clinical chromosomal microarray analysis and breakpoint junction sequence analysis. RESULTS: High-density customized array showed that the majority of cases (33/50; ~ 66%) present with single duplications, although complex genomic rearrangements (CGRs) are also frequent (17/50; ~ 34%). Breakpoint mapping to nucleotide resolution revealed further previously unknown structural and sequence complexities, even in single duplications. Meta-analysis of all studied rearrangements that occur at the PLP1 locus showed that single duplications were found in ~ 54% of individuals and that, among all CGR cases, triplication flanked by duplications is the most frequent CGR array CGH pattern observed. Importantly, in ~ 32% of join-points, there is evidence for a mutational signature of microhomeology (highly similar yet imperfect sequence matches). CONCLUSIONS: These data reveal a high frequency of CGRs at the PLP1 locus and support the assertion that replication-based mechanisms are prominent contributors to the formation of CGRs at Xq22. We propose that microhomeology can facilitate template switching, by stabilizing strand annealing of the primer using W-C base complementarity, and is a mutational signature for replicative repair.

• MeSH
• body zlomu chromozomu MeSH
• duplikace genu MeSH
• genetická predispozice k nemoci MeSH
• genetické asociační studie MeSH
• genom lidský MeSH
• genomika metody   MeSH
• genová přestavba * MeSH
• jednonukleotidový polymorfismus MeSH
• lidé MeSH
• mutace * MeSH
• myelinový proteolipidový protein genetika   MeSH
• nestabilita genomu MeSH
• srovnávací genomová hybridizace MeSH
• variabilita počtu kopií segmentů DNA * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Mutations in MORC2 lead to an axonal form of Charcot-Marie-Tooth (CMT) neuropathy type 2Z. To date, 31 families have been described with mutations in MORC2, indicating that this gene is frequently involved in axonal CMT cases. While the genetic data clearly establish the causative role of MORC2 in CMT2Z, the impact of its mutations on neuronal biology and their phenotypic consequences in patients remains to be clarified. We show that the full-length form of MORC2 is highly expressed in both embryonic and adult human neural tissues and that Morc2 expression is dynamically regulated in both the developing and the maturing murine nervous system. To determine the effect of the most common MORC2 mutations, p.S87L and p.R252W, we used several in vitro cell culture paradigms. Both mutations induced transcriptional changes in patient-derived fibroblasts and when expressed in rodent sensory neurons. These changes were more pronounced and accompanied by abnormal axonal morphology, in neurons expressing the MORC2 p.S87L mutation, which is associated with a more severe clinical phenotype. These data provide insight into the neuronal specificity of the mutated MORC2-mediated phenotype and highlight the importance of neuronal cell models to study the pathophysiology of CMT2Z.

• MeSH
• axony metabolismus   patologie   MeSH
• Charcotova-Marieova-Toothova nemoc genetika   patologie   MeSH
• embryonální kmenové buňky metabolismus   MeSH
• fibroblasty metabolismus   patologie   MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• mutace genetika   MeSH
• nervové kmenové buňky MeSH
• nervové receptory metabolismus   patologie   MeSH
• regulace genové exprese genetika   MeSH
• transkripční faktory genetika   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Patients with the neurological disorder HSAN-I suffer frequent infections, attributed to a lack of pain sensation and failure to seek care for minor injuries. Whether protective CD8+ T cells are affected in HSAN-I patients remains unknown. Here, we report that HSAN-I-associated mutations in serine palmitoyltransferase subunit SPTLC2 dampened human T cell responses. Antigen stimulation and inflammation induced SPTLC2 expression, and murine T-cell-specific ablation of Sptlc2 impaired antiviral-T-cell expansion and effector function. Sptlc2 deficiency reduced sphingolipid biosynthetic flux and led to prolonged activation of the mechanistic target of rapamycin complex 1 (mTORC1), endoplasmic reticulum (ER) stress, and CD8+ T cell death. Protective CD8+ T cell responses in HSAN-I patient PBMCs and Sptlc2-deficient mice were restored by supplementing with sphingolipids and pharmacologically inhibiting ER stress-induced cell death. Therefore, SPTLC2 underpins protective immunity by translating extracellular stimuli into intracellular anabolic signals and antagonizes ER stress to promote T cell metabolic fitness.

• MeSH
• CD8-pozitivní T-lymfocyty imunologie   MeSH
• cytokiny biosyntéza   MeSH
• dědičné senzorické a autonomní neuropatie genetika   MeSH
• kultivované buňky MeSH
• lidé středního věku MeSH
• lidé MeSH
• lymfocytární choriomeningitida imunologie   virologie   MeSH
• mechanistické cílové místo rapamycinového komplexu 1 metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• proliferace buněk MeSH
• serin-C-palmitoyltransferasa genetika   MeSH
• sfingolipidy biosyntéza   MeSH
• signální transdukce imunologie   MeSH
• stres endoplazmatického retikula genetika   imunologie   MeSH
• virus lymfocytární choriomeningitidy imunologie   MeSH
• zvířata MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Biallelic SBF2 mutations cause Charcot-Marie-Tooth disease type 4B2 (CMT4B2), a sensorimotor neuropathy with autosomal recessive inheritance and association with glaucoma. Since the discovery of the gene mutation, only few additional patients have been reported. We identified seven CMT4B2 families with nine different SBF2 mutations. Revisiting genetic and clinical data from our cohort and the literature, SBF2 variants were private mutations, including exon-deletion and de novo variants. The neuropathy typically started in the first decade after normal early motor development, was predominantly motor and had a rather moderate course. Electrophysiology and nerve biopsies indicated demyelination and excess myelin outfoldings constituted a characteristic feature. While neuropathy was >90% penetrant at age 10 years, glaucoma was absent in ~40% of cases but sometimes developed with age. Consequently, SBF2 mutation analysis should not be restricted to individuals with coincident neuropathy and glaucoma, and CMT4B2 patients without glaucoma should be followed for increased intraocular pressure. The presence of exon-deletion and de novo mutations demands comprehensive mutation scanning and family studies to ensure appropriate diagnostic approaches and genetic counseling.

• MeSH
• biopsie MeSH
• Charcotova-Marieova-Toothova nemoc diagnóza   genetika   MeSH
• dítě MeSH
• dospělí MeSH
• fenotyp * MeSH
• genetická predispozice k nemoci * MeSH
• genetické asociační studie * metody   MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutace * MeSH
• nereceptorové tyrosinfosfatasy genetika   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• metaanalýza MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

BACKGROUND: Charcot-Marie-Tooth type 2 (CMT2) neuropathy is characterised by a vast clinical and genetic heterogeneity complicating its diagnosis and therapeutic intervention. Identification of molecular signatures that are common to multiple CMT2 subtypes can aid in developing therapeutic strategies and measuring disease outcomes. METHODS: A proteomics-based approach was performed on lymphoblasts from CMT2 patients genetically diagnosed with different gene mutations to identify differentially regulated proteins. The candidate proteins were validated through real-time quantitative PCR and western blotting on lymphoblast samples of patients and controls, motor neurons differentiated from patient-derived induced pluripotent stem cells (iPSCs) and sciatic nerves of CMT2 mouse models. RESULTS: Proteomic profiling of patient lymphoblasts resulted in the identification of profilin 2 (PFN2) and guanidinoacetate methyltransferase (GAMT) as commonly downregulated proteins in different genotypes compared with healthy controls. This decrease was also observed at the transcriptional level on screening 43 CMT2 patients and 22 controls, respectively. A progressive decrease in PFN2 expression with age was observed in patients, while in healthy controls its expression increased with age. Reduced PFN2 expression was also observed in motor neurons differentiated from CMT2 patient-derived iPSCs and sciatic nerves of CMT2 mice when compared with controls. However, no change in GAMT levels was observed in motor neurons and CMT2 mouse-derived sciatic nerves. CONCLUSIONS: We unveil PFN2 and GAMT as molecular determinants of CMT2 with possible indications of the role of PFN2 in the pathogenesis and disease progression. This is the first study describing biomarkers that can boost the development of therapeutic strategies targeting a wider spectrum of CMT2 patients.

• MeSH
• axony patologie   MeSH
• Charcotova-Marieova-Toothova nemoc genetika   patologie   MeSH
• dospělí MeSH
• fenotyp MeSH
• genotyp * MeSH
• guanidinacetát-N-methyltransferasa genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mutace * MeSH
• profiliny genetika   MeSH
• proteomika MeSH
• rodokmen MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH