scholarly journals Phenotypical and Myopathological Consequences of Compound Heterozygous Missense and Nonsense Variants in SLC18A3

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3481
Author(s):  
Adela Della Marina ◽  
Annabelle Arlt ◽  
Ulrike Schara-Schmidt ◽  
Christel Depienne ◽  
Andrea Gangfuß ◽  
...  
Keyword(s):  
Animal Models ◽  
Molecular Genetic ◽  
Microscopic Investigation ◽  
Muscle Pathology ◽  
Compound Heterozygous ◽  
Pathogenic Variants ◽  
Microscopic Studies ◽  
Lipid Aggregates ◽  
The Impact ◽  
Detrimental Impact

Background: Presynaptic forms of congenital myasthenic syndromes (CMS) due to pathogenic variants in SLC18A3 impairing the synthesis and recycling of acetylcholine (ACh) have recently been described. SLC18A3 encodes the vesicular ACh transporter (VAChT), modulating the active transport of ACh at the neuromuscular junction, and homozygous loss of VAChT leads to lethality. Methods: Exome sequencing (ES) was carried out to identify the molecular genetic cause of the disease in a 5-year-old male patient and histological, immunofluorescence as well as electron- and CARS-microscopic studies were performed to delineate the muscle pathology, which has so far only been studied in VAChT-deficient animal models. Results: ES unraveled compound heterozygous missense and nonsense variants (c.315G>A, p.Trp105* and c.1192G>C, p.Asp398His) in SLC18A3. Comparison with already-published cases suggests a more severe phenotype including impaired motor and cognitive development, possibly related to a more severe effect of the nonsense variant. Therapy with pyridostigmine was only partially effective while 3,4 diaminopyridine showed no effect. Microscopic investigation of the muscle biopsy revealed reduced fibre size and a significant accumulation of lipid droplets. Conclusions: We suggest that nonsense variants have a more detrimental impact on the clinical manifestation of SLC18A3-associated CMS. The impact of pathogenic SLC18A3 variants on muscle fibre integrity beyond the effect of denervation is suggested by the build-up of lipid aggregates. This in turn implicates the importance of proper VAChT-mediated synthesis and recycling of ACh for lipid homeostasis in muscle cells. This hypothesis is further supported by the pathological observations obtained in previously published VAChT-animal models.

scholarly journals Genetic Spectrum of Syndromic and Non-Syndromic Hearing Loss in Pakistani Families

Genes ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1329
Author(s):  
Julia Doll ◽  
Barbara Vona ◽  
Linda Schnapp ◽  
Franz Rüschendorf ◽  
Imran Khan ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Exome Sequencing ◽  
Splice Site ◽  
Genetic Heterogeneity ◽  
Bioinformatics Analysis ◽  
Molecular Genetic ◽  
Compound Heterozygous ◽  
Pathogenic Variants ◽  
Syndromic Hearing Loss ◽  
Pakistani Families

The current molecular genetic diagnostic rates for hereditary hearing loss (HL) vary considerably according to the population background. Pakistan and other countries with high rates of consanguineous marriages have served as a unique resource for studying rare and novel forms of recessive HL. A combined exome sequencing, bioinformatics analysis, and gene mapping approach for 21 consanguineous Pakistani families revealed 13 pathogenic or likely pathogenic variants in the genes GJB2, MYO7A, FGF3, CDC14A, SLITRK6, CDH23, and MYO15A, with an overall resolve rate of 61.9%. GJB2 and MYO7A were the most frequently involved genes in this cohort. All the identified variants were either homozygous or compound heterozygous, with two of them not previously described in the literature (15.4%). Overall, seven missense variants (53.8%), three nonsense variants (23.1%), two frameshift variants (15.4%), and one splice-site variant (7.7%) were observed. Syndromic HL was identified in five (23.8%) of the 21 families studied. This study reflects the extreme genetic heterogeneity observed in HL and expands the spectrum of variants in deafness-associated genes.

scholarly journals Persistent Hypoglycemia with Polycystic Kidneys: A Rare Combination – A Case Report

2020 ◽  
Vol 5 (3) ◽  
pp. 1-6
Author(s):  
Priya Prasher ◽  
Katherine Redmond ◽  
Hillarey Stone ◽  
James Bailes ◽  
Edward Nehus ◽  
...  
Keyword(s):  
Case Report ◽  
Promoter Region ◽  
Molecular Genetic ◽  
Missense Variant ◽  
Compound Heterozygous ◽  
Molecular Genetic Testing ◽  
Coding Region ◽  
Polycystic Kidney ◽  
Homozygous State ◽  
Pathogenic Variants

We present the case of an infant referred to our NICU born at 39 weeks’ gestation with persistent hypoglycemia with elevated insulin levels (HI) requiring diazoxide to maintain normoglycemia. Additionally, polycystic kidney disease (PKD) was detected by ultrasound. Molecular genetic testing revealed pathogenic variants in the <i>PMM2</i>gene, i.e., a variant in the promoter region and a missense variant in the coding region. The precoding variant was recently described in 11 European families with similar phenotypes, either in a homozygous state or as compound heterozygous with a pathogenic coding variant. In neonates with HI associated with PKD, this rare recessive disorder should be considered.

scholarly journals Muscular and Molecular Pathology Associated with SPATA5 Deficiency in a Child with EHLMRS

2021 ◽  
Vol 22 (15) ◽  
pp. 7835
Author(s):  
Frederik Braun ◽  
Andreas Hentschel ◽  
Albert Sickmann ◽  
Theodore Marteau ◽  
Swantje Hertel ◽  
...  
Keyword(s):  
Molecular Pathology ◽  
Muscle Pathology ◽  
Compound Heterozygous ◽  
Proteomic Profiling ◽  
Mitochondrial Pathology ◽  
Microscopic Studies ◽  
Molecular Etiology ◽  
Relevant Compound ◽  
Mitochondrial Morphogenesis ◽  
Compound Heterozygous Variants

Mutations in the SPATA5 gene are associated with epilepsy, hearing loss and mental retardation syndrome (EHLMRS). While SPATA5 is ubiquitously expressed and is attributed a role within mitochondrial morphogenesis during spermatogenesis, there is only limited knowledge about the associated muscular and molecular pathology. This study reports on a comprehensive workup of muscular pathology, including proteomic profiling and microscopic studies, performed on an 8-year-old girl with typical clinical presentation of EHLMRS, where exome analysis revealed two clinically relevant, compound-heterozygous variants in SPATA5. Proteomic profiling of a quadriceps biopsy showed the dysregulation of 82 proteins, out of which 15 were localized in the mitochondrion, while 19 were associated with diseases presenting with phenotypical overlap to EHLMRS. Histological staining of our patient’s muscle biopsy hints towards mitochondrial pathology, while the identification of dysregulated proteins attested to the vulnerability of the cell beyond the mitochondria. Through our study we provide insights into the molecular etiology of EHLMRS and provide further evidence for a muscle pathology associated with SPATA5 deficiency, including a pathological histochemical pattern accompanied by dysregulated protein expression.

scholarly journals Simultaneous Identification of Both MFSD8 and RDH12 Pathogenic Variants in a Chinese Family Affected With Retinitis Pigmentosa

2021 ◽  
Vol 12 ◽  
Author(s):  
Yihui Wang ◽  
Yanling Teng ◽  
Desheng Liang ◽  
Zhuo Li ◽  
Lingqian Wu
Keyword(s):  
Retinitis Pigmentosa ◽  
Molecular Genetic ◽  
Cerebellar Atrophy ◽  
Compound Heterozygous Mutation ◽  
Chinese Family ◽  
Heterozygous Mutation ◽  
Compound Heterozygous ◽  
Homozygous Mutation ◽  
Pathogenic Variants ◽  
Reproductive Counseling

Retinitis pigmentosa (RP) is characterized by tremendous genetic and phenotypic heterogeneity. Here, we investigate the pathogeny of RP in a family to provide evidence for genetic and reproductive counseling for families. Although this pregnant woman of 8+3 weeks presented with RP, her first baby was born with RP, epilepsy, and cerebellar atrophy. The research identified a compound heterozygous mutation (c.998+3_998+6del/deletion) in the MFSD8 gene of the first born, explaining the cause of the proband’s disease, which cannot explain the mother’s. Then, a homozygous mutation c.343+1G &gt; A in RDH12 of the mother was found. RT-PCR is employed to find that there is a skipping of exon 10 in MFSD8 and a 15-nucleotide retention of intron5 in RDH12. The coexistence of two independent instances of RP caused by distinct genes in one pedigree is demonstrated. Based on the diagnosis, a prenatal diagnosis performed on the fetus found that the fetus’s MFSD8 is affected by the same mutation as the proband. The research underscoring the complexity of RP and the need for the combination of extensive molecular genetic testing and clinical characterization in addition expands the spectrum of MFSD8 mutations. Finally, it is expected that the family members would be prevented from reproducing children with the similar disease.

scholarly journals Gene and Phenotype Expansion of Unexplained Early Infantile Epileptic Encephalopathy

2021 ◽  
Vol 12 ◽  
Author(s):  
Xianyu Liu ◽  
Qiyang Shen ◽  
Guo Zheng ◽  
Hu Guo ◽  
Xiaopeng Lu ◽  
...  
Keyword(s):  
De Novo ◽  
Homology Modelling ◽  
Epileptic Encephalopathy ◽  
Therapeutic Interventions ◽  
Compound Heterozygous ◽  
Pathogenic Variants ◽  
Heterozygous Variant ◽  
Single Centre Study ◽  
Next Generation Sequencing Ngs ◽  
The Impact

Objective: The genetic aetiology of epileptic encephalopathy (EE) is growing rapidly based on next generation sequencing (NGS) results. In this single-centre study, we aimed to investigate a cohort of Chinese children with early infantile epileptic encephalopathy (EIEE).Methods: NGS was performed on 50 children with unexplained EIEE. The clinical profiles of children with pathogenic variants were characterised and analysed in detail. Conservation analysis and homology modelling were performed to predict the impact of STXBP1 variant on the protein structure.Results: Pathogenic variants were identified in 17 (34%) of 50 children. Sixteen variants including STXBP1 (n = 2), CDKL5 (n = 2), PAFAH1B1, SCN1A (n = 9), SCN2A, and KCNQ2 were de novo, and one (PIGN) was a compound heterozygous variant. The phenotypes of the identified genes were broadened. PIGN phenotypic spectrum may include EIEE. The STXBP1 variants were predicted to affect protein stability.Significance: NGS is a useful diagnostic tool for EIEE and contributes to expanding the EIEE-associated genotypes. Early diagnosis may lead to precise therapeutic interventions and can improve the developmental outcome.

scholarly journals Two Novel Compound Heterozygous Pathogenic Variants in P2YR12 gene

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1154-1154
Author(s):  
Arnaud Dupuis ◽  
Doris Böckelmann ◽  
Patricia Laeuffer ◽  
Katharina Neubauer ◽  
Christian Gachet ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Platelet Aggregation ◽  
Molecular Genetic ◽  
Index Patient ◽  
Molecular Genetic Analysis ◽  
Compound Heterozygous ◽  
Twin Brother ◽  
Pathogenic Variants ◽  
Fibrinogen Binding ◽  
Novel Variants

Abstract Introduction: P2Y12 receptor (P2Y12R) defect is a rare hemorrhagic disorder characterized by mild to moderate bleeding diathesis with easy bruising, mucosal bleedings, and excessive post-operative hemorrhage. It is due to mutations of the P2YR12 gene resulting in impairment of platelet responses to adenosine 5'-diphosphate (ADP) and subsequently to any other agonist as ADP is secreted from the dense granules during platelet activation. The P2Y12R plays a key role in platelet aggregation by amplifying the platelet activation process which is necessary to ensure appropriate primary hemostasis. The activation of the P2Y12R by ADP results in inhibition of adenylyl cyclase (AC) and in activation of phosphoinositide 3-kinase (PIK3), which amplifies and sustains the platelet aggregation response. To date only 12 pathogenic variants in the P2YR12 gene are listed in the Human Gene Mutation Database (HGMD®) (10 missense/nonsense mutations and 2 small deletions). Seven missense mutations are described in the literature in patients suffering from bleeding disorders of various severity. Autosomal recessive (homozygous and compound heterozygous pathogenic variants) as well as autosomal dominant (only one heterozygous pathogenic variant) inheritance has been reported. Patients and Methods: We investigated an 8 year old index patient who came to our outpatient clinic to investigate an increased bleeding tendency. He suffered from easy bruising and reported increased bleeding after tonsillectomy. His twin brother was also affected regarding bleeding disorder. Their father suffered sometimes from epistaxis, their mother and three older siblings were clinically unaffected. Platelet functions were assessed by light transmission aggregometry using citrated PRP. Membrane glycoprotein quantification, fibrinogen binding, von Willebrand factor (VWF) binding and the VASP assay were performed by flow cytometry. Molecular genetic analysis (Sanger sequencing) was performed for all exons including UTR regions and splice sites of the P2RY12-gene (NM_002788.4) for the twins and their parents. Results: The index patient and his brother showed normal values for platelet count, aPTT, INR, FXIII and VWF parameters. Both twins showed impaired platelet aggregation after stimulation with collagen, ADP and epinephrine. For both the index patient and his twin brother ADP (4-20 µM and 4-10 µM respectively) induced aggregation was markedly reduced and rapidly reversible. Flow cytometry revealed severely decreased fibrinogen binding for the index patient and his twin brother after stimulation with ADP (0.25-5.0 μmol/l) compared to control platelets. For CD42a/b (GP Ib/IX-complex), CD41 (GP IIb/IIIa-complex), ristocetin-induced VWF-binding, CD62- and CD63-expression, normal values were measured. The VASP assay revealed a strong defect with a PRI value of patient's platelets as low as 1.2% and 1% respectively (normal range > 69%). Molecular genetic analysis revealed two novel variants in the P2YR12 coding sequence (Tab.1). Conclusion: We have identified two novel variants in the P2YR12 gene with pathogenic predictions in a compound heterozygous state in twin brothers suffering from a chronic bleeding disorder. Flow cytometry analyses (fibrinogen binding) and VASP analyses are valuable tools to diagnose a platelet ADP-receptor defect. Table Table. Disclosures No relevant conflicts of interest to declare.

Molecular genetic markers for thyroid FNAB

2015 ◽  
Vol 54 (03) ◽  
pp. 94-100 ◽  
Author(s):  
P. B. Musholt ◽  
T. J. Musholt
Keyword(s):  
Genetic Markers ◽  
Thyroid Nodules ◽  
Molecular Genetic ◽  
Genetic Alterations ◽  
Diagnostic Tools ◽  
Ultrasound Screening ◽  
Thyroid Malignancy ◽  
Thyroid Carcinomas ◽  
Molecular Genetic Markers ◽  
The Impact

SummaryAim: Thyroid nodules > 1 cm are observed in about 12% of unselected adult employees aged 18–65 years screened by ultrasound scan (40). While intensive ultrasound screening leads to early detection of thyroid diseases, the determination of benign or malignant behaviour remains uncertain and may trigger anxieties in many patients and their physicians. A considerable number of thyroid resections are consecutively performed due to suspicion of malignancy in the detected nodes. Fine needle aspiration biopsy (FNAB) has been recommended for the assessment of thyroid nodules to facilitate detection of thyroid carcinomas but also to rule out malignancy and thereby avoid unnecessary thyroid resections. However, cytology results are dependent on experience of the respective cytologist and unfortunately inconclusive in many cases. Methods: Molecular genetic markers are already used nowadays to enhance sensitivity and specificity of FNAB cytology in some centers in Germany. The most clinically relevant molecular genetic markers as pre-operative diagnostic tools and the clinical implications for the intraoperative and postoperative management were reviewed. Results: Molecular genetic markers predominantly focus on the preoperative detection of thyroid malignancies rather than the exclusion of thyroid carcinomas. While some centers routinely assess FNABs, other centers concentrate on FNABs with cytology results of follicular neoplasia or suspicion of thyroid carcinoma. Predominantly mutations of BRAF, RET/PTC, RAS, and PAX8/PPARγ or expression of miRNAs are analyzed. However, only the detection of BRAF mutations predicts the presence of (papillary) thyroid malignancy with almost 98% probability, indicating necessity of oncologic thyroid resections irrespective of the cytology result. Other genetic alterations are associated with thyroid malignancy with varying frequency and achieve less impact on the clinical management. Conclusion: Molecular genetic analysis of FNABs is increasingly performed in Germany. Standardization, quality controls, and validation of various methods need to be implemented in the near future to be able to compare the results. With increasing knowledge about the impact of genetic alterations on the prognosis of thyroid carcinomas, recommendations have to be defined that may lead to individually optimized treatment strategies.

Clinical application of polymorphic variants of the genes ESR1 and CYP2D6*4 in patients with breast and endometrial cancer

2017 ◽  
pp. 132-138
Author(s):  
O.V. Paliychuk ◽  
◽  
L.Z. Polishchuk ◽  
Z.I. Rossokha ◽  
◽  
...  
Keyword(s):  
Breast Cancer ◽  
Endometrial Cancer ◽  
Hormone Therapy ◽  
Molecular Genetic ◽  
Cancer Syndrome ◽  
Genetic Characteristics ◽  
Multiple Tumors ◽  
Receptor Status ◽  
Genetic Examination ◽  
The Impact

The objective: determining gene polymorphism features ERS1, CYP2D6 in patients with breast cancer (RHZ) and endometrial cancer (EC) and the impact assessment studied genetic characteristics compared to receptor status (immunohistochemical determination of expression levels of ER, PR) tumors and the results of the treatment. Patients and methods. article presents the results of complex clinical, morphological, clinical-genealogical, and molecular-genetic examination of 28 females: 19 patients with breast cancer (BC), 9 patients with endometrial cancer (EC), including 5 patients with primary-multiple tumors (PMT) with and without tumor pathology aggregation in families. Results. The It was determined that in patients’ families malignant tumors of breast, uterine body and/or ovaries prevail that corresponds to Lynch type II syndrome (family cancer syndrome). Molecular-genetic examination of genomic DNA of peripheral blood and histological sections for the presence of SNPs of ESR and CYP2D6*4 genes comparing with the results of immunohistochemical study of tumors for receptors ER and PR status have not found associations between these characteristics; although among EC patients the occurrence of genotypes 397ТТ and 351АА was significantly higher comparing with BC patients (55.55% and 10.5% for genotype 397ТТ,and 15.8% for genotype 351АА, respectively). At the same time the patients with BC and primary-multiple tumors (PMT) of female reproductive system organs (FRSO) that carried mutations in BRCA1 in all the cases demonstrated positive ER and PR receptor status and adverse combinations of polymorphous variants of the genes ESR1 (397СС, 397ТС) and CYP2D6*4 (1846G, 1846GA), suggesting combined effect of these factors on the development of malignant neoplasias of FRSO in families with positive family cancer history. In BC patients, receiving standard hormone therapy with tamoxifen, those, who had genotype 1846GG of the gene CYP2D6*4, in 3 patients (15.8%) of 19 (100%) patients disease recurrence was diagnosed. Conclusion. The obtained results allow clinical use of the assessment of polymorphism frequency of the genes ESR1 and CYP2D6*4 for selection of individual hormone therapy regimens schemes for BC patients, to increase efficacy of dispensary observation after finishing of special therapy for such patients, and also personalization of complex and combined treatment regimens. Key words: breast cancer, endometrial cancer, family cancer syndrome, single nucleotide polymorphisms (SNPs) of the genes ESR1, CYP2D6*4.

scholarly journals Consideration of Gut Microbiome in Murine Models of Diseases

2021 ◽  
Vol 9 (5) ◽  
pp. 1062
Author(s):  
Chunye Zhang ◽  
Craig L. Franklin ◽  
Aaron C. Ericsson
Keyword(s):  
Animal Models ◽  
Mouse Models ◽  
Biomedical Research ◽  
Gut Microbiome ◽  
Close Association ◽  
Disease Model ◽  
Potential Contributor ◽  
Potential Factors ◽  
Models Of Disease ◽  
The Impact

The gut microbiome (GM), a complex community of bacteria, viruses, protozoa, and fungi located in the gut of humans and animals, plays significant roles in host health and disease. Animal models are widely used to investigate human diseases in biomedical research and the GM within animal models can change due to the impact of many factors, such as the vendor, husbandry, and environment. Notably, variations in GM can contribute to differences in disease model phenotypes, which can result in poor reproducibility in biomedical research. Variation in the gut microbiome can also impact the translatability of animal models. For example, standard lab mice have different pathogen exposure experiences when compared to wild or pet store mice. As humans have antigen experiences that are more similar to the latter, the use of lab mice with more simplified microbiomes may not yield optimally translatable data. Additionally, the literature describes many methods to manipulate the GM and differences between these methods can also result in differing interpretations of outcomes measures. In this review, we focus on the GM as a potential contributor to the poor reproducibility and translatability of mouse models of disease. First, we summarize the important role of GM in host disease and health through different gut–organ axes and the close association between GM and disease susceptibility through colonization resistance, immune response, and metabolic pathways. Then, we focus on the variation in the microbiome in mouse models of disease and address how this variation can potentially impact disease phenotypes and subsequently influence research reproducibility and translatability. We also discuss the variations between genetic substrains as potential factors that cause poor reproducibility via their effects on the microbiome. In addition, we discuss the utility of complex microbiomes in prospective studies and how manipulation of the GM through differing transfer methods can impact model phenotypes. Lastly, we emphasize the need to explore appropriate methods of GM characterization and manipulation.

scholarly journals Bi-allelic variants in MTMR5/SBF1 cause Charcot-Marie-Tooth type 4B3 featuring mitochondrial dysfunction

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Beatrice Berti ◽  
Giovanna Longo ◽  
Francesco Mari ◽  
Stefano Doccini ◽  
Ilaria Piccolo ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Mitochondrial Dysfunction ◽  
Early Onset ◽  
Integrated Approach ◽  
Compound Heterozygous ◽  
Charcot Marie Tooth ◽  
Charcot Marie Tooth Disease ◽  
Pathogenic Variants ◽  
First Case ◽  
Spine Mri

Abstract Background Charcot-Marie-Tooth disease (CMT) type 4B3 (CMT4B3) is a rare form of genetic neuropathy associated with variants in the MTMR5/SBF1 gene. MTMR5/SBF1 is a pseudophosphatase predicted to regulate endo-lysosomal trafficking in tandem with other MTMRs. Although almost ubiquitously expressed, pathogenic variants primarily impact on the peripheral nervous system, corroborating the involvement of MTMR5/SBF1 and its molecular partners in Schwann cells-mediated myelinization. Case presentation We report a case of severe CMT4B3 characterized by early-onset motor and axonal polyneuropathy in an Italian child in absence of any evidence of brain and spine MRI abnormalities or intellectual disability and with a biochemical profile suggestive of mitochondrial disease. Using an integrated approach combining both NGS gene panels and WES analysis, we identified two novel compound heterozygous missense variants in MTMR5/SBF1 gene, p.R763H (c.2291G > A) and p.G1064E (c.3194G > A). Studies in muscle identified partial defects of oxidative metabolism. Conclusion We describe the first case of an early onset severe polyneuropathy with motor and axonal involvement, due to recessive variants in the MTMR5/SBF1 gene, with no evidence of brain and spine MRI abnormalities, intellectual disability, no clinical and neurophysiological evidences of distal sensory impairment, and rapid neuromuscular deterioration. This report suggests that MTMR5/SBF1 should be considered in cases of infantile-onset CMT with secondary mitochondrial dysfunction.

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