scholarly journals The identification of a novel splicing mutation in the DMD gene of a Chinese family

2021 ◽  
Author(s):  
Wanlu Liu ◽  
Xinwei Shi ◽  
Yuqi Li ◽  
Fuyuan Qiao ◽  
Yuanyuan Wu
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Pathogenic Mutation ◽  
Chinese Family ◽  
Gene Variants ◽  
Splicing Mutation ◽  
Aberrant Splicing ◽  
Disease Phenotypes ◽  
Dmd Gene ◽  
Minigene Expression

The Duchenne Muscular Dystrophy (DMD) gene variants are associated with the disease phenotypes. The pathogenic mutation, c.2293-1G>C, was detected in DMD gene in the proband and the fetus, which has not been reported in the literature.The minigene expression in vitro confirmed that c.2293-1G>C is responsible of aberrant splicing.

scholarly journals Single Exon Skipping Can Address a Multi-Exon Duplication in the Dystrophin Gene

2020 ◽  
Vol 21 (12) ◽  
pp. 4511 ◽  
Author(s):  
Kane Greer ◽  
Russell Johnsen ◽  
Yoram Nevo ◽  
Yakov Fellig ◽  
Susan Fletcher ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Exon Skipping ◽  
Dystrophin Gene ◽  
Duchenne Muscular Dystrophy Patient ◽  
Exon Duplication ◽  
Dmd Gene ◽  
Muscle Wasting Disease ◽  
Phosphorodiamidate Morpholino Oligomers

Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease typically caused by protein-truncating mutations that preclude synthesis of a functional dystrophin. Exonic deletions are the most common type of DMD lesion, however, whole exon duplications account for between 10–15% of all reported mutations. Here, we describe in vitro evaluation of antisense oligonucleotide-induced splice switching strategies to re-frame the transcript disrupted by a multi-exon duplication within the DMD gene. Phosphorodiamidate morpholino oligomers and phosphorodiamidate morpholino oligomers coupled to a cell penetrating peptide were evaluated in a Duchenne muscular dystrophy patient cell strain carrying an exon 14–17 duplication. Two strategies were employed; the conventional approach was to remove both copies of exon 17 in addition to exon 18, and the second strategy was to remove only the first copy of exon 17. Both approaches result in a larger than normal but in-frame DMD transcript, but surprisingly, the removal of only the first exon 17 appeared to be more efficient in restoring dystrophin, as determined using western blotting. The emergence of a normal sized DMD mRNA transcript that was not apparent in untreated samples may have arisen from back splicing and could also account for some of the dystrophin protein being produced.

scholarly journals The identification of a novel splicing mutation in the DMD gene of a Chinese family

2021 ◽  
Vol 9 (12) ◽  
Author(s):  
Wanlu Liu ◽  
Xinwei Shi ◽  
Yuqi Li ◽  
Fuyuan Qiao ◽  
Yuanyuan Wu
Keyword(s):  
Chinese Family ◽  
Splicing Mutation ◽  
Dmd Gene

Have Duchenne Muscular Dystrophy Patients an Increased Cancer Risk?

2021 ◽  
pp. 1-5
Author(s):  
Gian Luca Vita ◽  
Luisa Politano ◽  
Angela Berardinelli ◽  
Giuseppe Vita
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Systematic Investigation ◽  
Mdx Mice ◽  
True Incidence ◽  
Patients With Cancer ◽  
Dmd Gene ◽  
Age Range ◽  
Prevalence Of Cancer

Background: Increasing evidence suggests that Duchenne muscular dystrophy (DMD) gene is involved in the occurrence of different types of cancer. Moreover, development of sarcomas was reported in mdx mice, the murine model of DMD, in older age. So far, nine isolated DMD patients were reported with concomitant cancer, four of whom with rhabdomyosarcoma (RMS), but no systematic investigation was performed about the true incidence of cancer in DMD. Methods: All members of the Italian Association of Myology were asked about the occurrence of cancer in their DMD patients in the last 30 years. Results: Four DMD patients with cancer were reported after checking 2455 medical records. One developed brain tumour at the age of 35 years. Two patients had alveolar RMS at 14 and 17 years of age. The fourth patient had a benign enchondroma when 11-year-old. Conclusion: Prevalence of cancer in general in the Italian DMD patients does not seem to be different from that in the general population with the same age range. Although the small numbers herein presented do not allow definitive conclusion, the frequent occurrence of RMS in DMD patients raises an alert for basic researchers and clinicians. The role of DMD gene in cancer merits further investigations.

scholarly journals Novel MSX1 variants identified in families with nonsyndromic oligodontia

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jinglei Zheng ◽  
Miao Yu ◽  
Haochen Liu ◽  
Tao Cai ◽  
Hailan Feng ◽  
...  
Keyword(s):  
Current Data ◽  
Phenotypic Characterization ◽  
Functional Evaluation ◽  
Gene Variants ◽  
Chinese Families ◽  
Whole Exome ◽  
Bioinformatics Databases ◽  
Uncertain Significance ◽  
Vitro Analysis

AbstractThe goal of this study was to identify MSX1 gene variants in multiple Chinese families with nonsyndromic oligodontia and analyse the functional influence of these variants. Whole-exome sequencing (WES) and Sanger sequencing were performed to identify the causal gene variants in five families with nonsyndromic oligodontia, and a series of bioinformatics databases were used for variant confirmation and functional prediction. Phenotypic characterization of the members of these families was described, and an in vitro analysis was performed for functional evaluation. Five novel MSX1 heterozygous variants were identified: three missense variants [c.662A>C (p.Q221P), c.670C>T (p.R224C), and c.809C>T (p.S270L)], one nonsense variant [c.364G>T (p.G122*)], and one frameshift variant [c.277delG (p.A93Rfs*67)]. Preliminary in vitro studies demonstrated that the subcellular localization of MSX1 was abnormal with the p.Q221P, p.R224C, p.G122*, and p.A93Rfs*67 variants compared to the wild type. Three variants (p.Q221P, p.G122*, and p.A93Rfs*67) were classified as pathogenic or likely pathogenic, while p.S270L and p.R224C were of uncertain significance in the current data. Moreover, we summarized and analysed the MSX1-related tooth agenesis positions and found that the type and variant locus were not related to the severity of tooth loss. Our results expand the variant spectrum of nonsyndromic oligodontia and provide valuable information for genetic counselling.

scholarly journals Nonsense variant of NR0B1 causes hormone disorders associated with congenital adrenal hyperplasia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Da-Bei Fan ◽  
Li Li ◽  
Hao-Hao Zhang
Keyword(s):  
Congenital Adrenal Hyperplasia ◽  
Energy Homeostasis ◽  
Hypogonadotropic Hypogonadism ◽  
Chinese Family ◽  
Orphan Nuclear Receptor ◽  
Inherited Disease ◽  
Adrenal Hyperplasia ◽  
Infancy And Early Childhood ◽  
Disordered Energy

AbstractCongenital adrenal hyperplasia (CAH) is a rare X-linked recessive inherited disease that is considered a major cause of steroidogenesis disorder and is associated with variants or complete deletion of the NR0B1 gene. The DAX-1 protein (encoded by NR0B1) is a vertebrate-specific orphan nuclear receptor and is also a transcriptional factor for adrenal and reproductive development. CAH usually causes adrenal insufficiency in infancy and early childhood, leading to hypogonadotropic hypogonadism in adulthood; however, few adult cases have been reported to date. In this study, we examined a Chinese family with one adult patient with CAH, and identified a putative variant of NR0B1 gene via next-generation sequencing (NGS), which was confirmed with Sanger sequencing. A novel nonsense variant (c.265C>T) was identified in the NR0B1 gene, which caused the premature termination of DAX-1 at residue 89 (p.G89*). Furthermore, mutant NR0B1 gene displayed a partial DAX-1 function, which may explain the late pathogenesis in our case. Additionally, qPCR revealed the abnormal expression of four important genes identified from ChIP-seq, which were associated with energy homeostasis and steroidogenesis, and were influenced by the DAX-1 mutant. In addition, hormone disorders can be caused by DAX-1 mutant and partially recovered by siRNA of PPARGC1A. Herein, we identified a novel nonsense variant (c.265C>T) of NR0B1 in a 24-year-old Chinese male who was suffering from CAH. This mutant DAX-1 protein was found to have disordered energy homeostasis and steroidogenesis based on in vitro studies, which was clinically consistent with the patient’s phenotypic features.

scholarly journals RTEL1 influences the abundance and localization of TERRA RNA

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Fiorella Ghisays ◽  
Aitor Garzia ◽  
Hexiao Wang ◽  
Claudia Canasto-Chibuque ◽  
Marcel Hohl ◽  
...  
Keyword(s):  
Cell Viability ◽  
Telomere Length ◽  
Human Cells ◽  
Helicase Domain ◽  
Telomere Repeat ◽  
Disease Phenotypes ◽  
G Quadruplex ◽  
Non Coding Rnas ◽  
Subtelomeric Regions

AbstractTelomere repeat containing RNAs (TERRAs) are a family of long non-coding RNAs transcribed from the subtelomeric regions of eukaryotic chromosomes. TERRA transcripts can form R-loops at chromosome ends; however the importance of these structures or the regulation of TERRA expression and retention in telomeric R-loops remain unclear. Here, we show that the RTEL1 (Regulator of Telomere Length 1) helicase influences the abundance and localization of TERRA in human cells. Depletion of RTEL1 leads to increased levels of TERRA RNA while reducing TERRA-containing R loops at telomeres. In vitro, RTEL1 shows a strong preference for binding G-quadruplex structures which form in TERRA. This binding is mediated by the C-terminal region of RTEL1, and is independent of the RTEL1 helicase domain. RTEL1 binding to TERRA appears to be essential for cell viability, underscoring the importance of this function. Degradation of TERRA-containing R-loops by overexpression of RNAse H1 partially recapitulates the increased TERRA levels and telomeric instability associated with RTEL1 deficiency. Collectively, these data suggest that regulation of TERRA is a key function of the RTEL1 helicase, and that loss of that function may contribute to the disease phenotypes of patients with RTEL1 mutations.

scholarly journals Differential Effects of Halofuginone Enantiomers on Muscle Fibrosis and Histopathology in Duchenne Muscular Dystrophy

2021 ◽  
Vol 22 (13) ◽  
pp. 7063
Author(s):  
Sharon Mordechay ◽  
Shaun Smullen ◽  
Paul Evans ◽  
Olga Genin ◽  
Mark Pines ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Motor Coordination ◽  
Mdx Mice ◽  
Cell Viability Assay ◽  
Muscle Fibrosis ◽  
Antifibrotic Therapy ◽  
Racemic Form ◽  
Viability Assay

Progressive loss of muscle and muscle function is associated with significant fibrosis in Duchenne muscular dystrophy (DMD) patients. Halofuginone, an analog of febrifugine, prevents fibrosis in various animal models, including those of muscular dystrophies. Effects of (+)/(−)-halofuginone enantiomers on motor coordination and diaphragm histopathology in mdx mice, the mouse model for DMD, were examined. Four-week-old male mice were treated with racemic halofuginone, or its separate enantiomers, for 10 weeks. Controls were treated with saline. Racemic halofuginone-treated mice demonstrated better motor coordination and balance than controls. However, (+)-halofuginone surpassed the racemic form’s effect. No effect was observed for (−)-halofuginone, which behaved like the control. A significant reduction in collagen content and degenerative areas, and an increase in utrophin levels were observed in diaphragms of mice treated with racemic halofuginone. Again, (+)-halofuginone was more effective than the racemic form, whereas (−)-halofuginone had no effect. Both racemic and (+)-halofuginone increased diaphragm myofiber diameters, with no effect for (−)-halofuginone. No effects were observed for any of the compounds tested in an in-vitro cell viability assay. These results, demonstrating a differential effect of the halofuginone enantiomers and superiority of (+)-halofuginone, are of great importance for future use of (+)-halofuginone as a DMD antifibrotic therapy.

Haploinsufficiency in non-homologous end joining factor 1 induces ovarian dysfunction in humans and mice

2021 ◽  
pp. jmedgenet-2020-107398
Author(s):  
Guoqing Li ◽  
Xi Yang ◽  
Lingbo Wang ◽  
Yuncheng Pan ◽  
Siyuan Chen ◽  
...  
Keyword(s):  
Ovarian Function ◽  
In Vitro Assays ◽  
Chinese Family ◽  
Common Disease ◽  
Loss Of Function ◽  
End Joining ◽  
Dsb Repair ◽  
Repair Capacity ◽  
Non Homologous End Joining

BackgroundPremature ovarian insufficiency (POI) is a common disease in women that leads to a reduced reproductive lifespan. The aetiology of POI is genetically heterogeneous, with certain double-strand break (DSB) repair genes being implicated in POI. Although non-homologous end joining (NHEJ) is an efficient DSB repair pathway, the functional relationship between this pathway and POI remains unknown.Methods and resultsWe conducted whole-exome sequencing in a Chinese family and identified a rare heterozygous loss-of-function variant in non-homologous end joining factor 1 (NHEJ1): c.532C>T (p.R178*), which co-segregated with POI and irregular menstruation. The amount of NHEJ1 protein in the proband was half of the normal level, indicating a link between NHEJ1 haploinsufficiency and POI. Furthermore, another rare heterozygous NHEJ1 variant c.500A>G (p.Y167C) was identified in one of 100 sporadic POI cases. Both variants were predicted to be deleterious by multiple in silico tools. In vitro assays showed that knock-down of NHEJ1 in human KGN ovarian cells impaired DNA repair capacity. We also generated a knock-in mouse model with a heterozygous Nhej1 variant equivalent to NHEJ1 p.R178* in familial patients. Compared with wild-type mice, heterozygous Nhej1-mutated female mice required a longer time to first birth, and displayed reduced numbers of primordial and growing follicles. Moreover, these mice exhibited higher sensitivity to DSB-inducing drugs. All these phenotypes are analogous to the progressive loss of ovarian function observed in POI.ConclusionsOur observations in both humans and mice suggest that NHEJ1 haploinsufficiency is associated with non-syndromic POI, providing novel insights into genetic counselling and clinical prevention of POI.

Malignant Hyperthermia in a Child with Duchenne Muscular Dystrophy

PEDIATRICS ◽  
1983 ◽  
Vol 71 (1) ◽  
pp. 118-119
Author(s):  
HOWARD M. KELFER ◽  
WILLIAM D. SINGER ◽  
ROBERT N. REYNOLDS
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Side Effects ◽  
Muscular Dystrophy ◽  
Malignant Hyperthermia ◽  
Muscle Biopsy ◽  
Biopsy Specimen ◽  
Laboratory Findings ◽  
Anesthetic Agents ◽  
In Vitro Response

Patients with Duchenne muscular dystrophy (DMD) are susceptible to numerous adverse intraoperative and postoperative side effects of anesthetic agents. These include: hyperthermia and hyperkalemia,1,2 systemic acidosis,3 cardiac abnormalities (tachycardia, arrhythmia, arrest),2-5 rhabdomyolysis,2-6 as well as death.2,5 These clinical and laboratory findings are similar to those associated with malignant hyperthermia (MH).7,8 Until this time no one has confirmed the association of MH, as reflected by these clinical phenomena, in a patient with DMD. We present a patient who manifested many features of MH immediately following confirmatory muscle biopsy for DMD under general anesthesia. In vitro response to testing of a muscle biopsy specimen was consistent with a diagnosis of malignant hyperthermia.

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