Unexpected DMD Gene Mutations Detected by CMA and CNV-seq in amniotic Fluid and Aborted Fetus Samples

Abstract Background: Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are common X chromosome-linked recessive hereditary diseases. The mechanism is that the exon mutations of anti-myatrophy protein gene (Dystrophin gene) and lead to muscle dysfunction. Prenatal diagnosis can prevent the birth of children with defects and have good clinical significance. Methods: CMA and CNV-seq were used to detect the amniotic fluid after amniocentesis,. CNV-seq was used to detect spontaneous abortion tissue. The DMD gene mutations were found in 6 amniotic fluid samples and one spontaneous abortion sample. DMD gene mutations were confirmed by MLPA and new DMD mutations were found.Results: CMA found DMD mutations :1.Xp21.1, 75.5kb del (E52-53); 2.Xp21.2, 334.92kb dup (E61-79); 3.Xp21.2, 292.25kb dup (E58-74); 4.Xp21.1, 374.20 kb dup (E45-51). CNV-seq found DMD mutations: 5.X p21.2, E64-79 dup; 6.X p21.1, E1-7dup; 7.Xp21.1, E 44-52 del. Conclusions: 4 fetuses harboring DMD gene mutations were found by CMA, 2 fetuses and 1 induced abortion carrying DMD gene mutations was detected by CNV-seq. CMA/CNV-seq jointed with MLPA test can provide more comprehensive evidence for prenatal diagnosis.

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Cardiac Involvement in Dystrophin-Deficient Females: Current Understanding and Implications for the Treatment of Dystrophinopathies

Genes ◽

10.3390/genes11070765 ◽

2020 ◽

Vol 11 (7) ◽

pp. 765 ◽

Cited By ~ 1

Author(s):

Kenji Rowel Q. Lim ◽

Narin Sheri ◽

Quynh Nguyen ◽

Toshifumi Yokota

Keyword(s):

Muscular Dystrophy ◽

Molecular Mechanisms ◽

Cardiac Involvement ◽

Gene Mutations ◽

Dystrophin Gene ◽

Becker Muscular Dystrophy ◽

Female Carrier ◽

Daily Life Activities ◽

Cardiac Manifestations ◽

Available Information

Duchenne muscular dystrophy (DMD) is a fatal X-linked recessive condition caused primarily by out-of-frame mutations in the dystrophin gene. In males, DMD presents with progressive body-wide muscle deterioration, culminating in death as a result of cardiac or respiratory failure. A milder form of DMD exists, called Becker muscular dystrophy (BMD), which is typically caused by in-frame dystrophin gene mutations. It should be emphasized that DMD and BMD are not exclusive to males, as some female dystrophin mutation carriers do present with similar symptoms, generally at reduced levels of severity. Cardiac involvement in particular is a pressing concern among manifesting females, as it may develop into serious heart failure or could predispose them to certain risks during pregnancy or daily life activities. It is known that about 8% of carriers present with dilated cardiomyopathy, though it may vary from 0% to 16.7%, depending on if the carrier is classified as having DMD or BMD. Understanding the genetic and molecular mechanisms underlying cardiac manifestations in dystrophin-deficient females is therefore of critical importance. In this article, we review available information from the literature on this subject, as well as discuss the implications of female carrier studies on the development of therapies aiming to increase dystrophin levels in the heart.

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Sensitivity and Frequencies of Dystrophin Gene Mutations in Thai DMD/BMD Patients As Detected by Multiplex PCR

Disease Markers ◽

10.1155/2008/521568 ◽

2008 ◽

Vol 25 (2) ◽

pp. 115-121 ◽

Cited By ~ 5

Author(s):

Thanyachai Sura ◽

Jakris Eu-ahsunthornwattana ◽

Sarinee Pingsuthiwong ◽

Manisa Busabaratana

Keyword(s):

Muscular Dystrophy ◽

Multiplex Pcr ◽

Gene Mutations ◽

Dystrophin Gene ◽

Index Patient ◽

Becker Muscular Dystrophy ◽

Large Size ◽

Different Populations ◽

The Mean ◽

Deletion Frequency

Background: Duchenne muscular dystrophy (DMD), a lethal X-linked disease affecting 1 in 3500 male births, and its more benign variant, Becker muscular dystrophy (BMD), are caused by mutations in the dystrophin gene. Because of its large size, analysing the whole gene is impractical. Methods have been developed to detect the commonest mutations i.e. the deletions of the exons. Although these tests are highly specific, their sensitivity is inherently limited by the prevalence of deletions, which differs among different populations.Methods: We reviewed our database for the detection of Dystrophin gene mutation by means of 31-exon multiplex PCR in Thai males, diagnosed clinically and biochemically with DMD or BMD from July 1994 to November 2006. One index patient was chosen from each family for statistical analysis. The overall sensitivity of the test, the number of fragment deleted, and the deletion frequency of each fragment were calculated, along with their 95% confidence intervals (C.I.).Results: We found deletions in 99 out of the 202 index patients (49%; Bayesian 95% C.I. = 42%–56%). 51% of these had deletion in only one of the 31 exons tested, while the patient with the most extensive deletions had 14 exons deleted. The mean number of deleted exons were 2.84 (BCabootstrap 95% C.I. = 2.37–3.48), or 5.02 (3.81–6.85) if all the untested exons adjacent to the confirmed deleted exons were assumed to be deleted. The region spanning exons 44-52 was the most frequently deleted. These were similar to those reported in the Japanese.Conclusion: The multiplex PCR detected deletions only in about half of the Thai patients. The diseases therefore should not be excluded solely on the negative result if DMD/BMD is strongly suspected.

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The lncRNA 44s2 Study Applicability to the Design of 45-55 Exon Skipping Therapeutic Strategy for DMD

Biomedicines ◽

10.3390/biomedicines9020219 ◽

2021 ◽

Vol 9 (2) ◽

pp. 219

Author(s):

Elena Gargaun ◽

Sestina Falcone ◽

Guilhem Solé ◽

Julien Durigneux ◽

Andoni Urtizberea ◽

...

Keyword(s):

Muscular Dystrophy ◽

Gene Mutations ◽

Exon Skipping ◽

Becker Muscular Dystrophy ◽

Protein Stabilization ◽

Progressive Muscular Dystrophy ◽

Dilatative Cardiomyopathy ◽

Proliferation And Differentiation ◽

Dmd Gene ◽

Dystrophin Protein

In skeletal muscle, long noncoding RNAs (lncRNAs) are involved in dystrophin protein stabilization but also in the regulation of myocytes proliferation and differentiation. Hence, they could represent promising therapeutic targets and/or biomarkers for Duchenne and Becker muscular dystrophy (DMD/BMD). DMD and BMD are X-linked myopathies characterized by a progressive muscular dystrophy with or without dilatative cardiomyopathy. Two-thirds of DMD gene mutations are represented by deletions, and 63% of patients carrying DMD deletions are eligible for 45 to 55 multi-exons skipping (MES), becoming BMD patients (BMDΔ45-55). We analyzed the genomic lncRNA presence in 38 BMDΔ45-55 patients and characterized the lncRNA localized in introns 44 and 55 of the DMD gene. We highlighted that all four lncRNA are differentially expressed during myogenesis in immortalized and primary human myoblasts. In addition, the lncRNA44s2 was pointed out as a possible accelerator of differentiation. Interestingly, lncRNA44s expression was associated with a favorable clinical phenotype. These findings suggest that lncRNA44s2 could be involved in muscle differentiation process and become a potential disease progression biomarker. Based on these results, we support MES45-55 therapy and propose that the design of the CRISPR/Cas9 MES45-55 assay consider the lncRNA sequences bordering the exonic 45 to 55 deletion.

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A different spectrum of DMD gene mutations in local Chinese patients with Duchenne/Becker muscular dystrophy

Chinese Medical Journal ◽

10.1097/00029330-200607010-00004 ◽

2006 ◽

Vol 119 (13) ◽

pp. 1079-1087 ◽

Cited By ~ 14

Author(s):

Lo Fai-man Ivan ◽

Lai Keung-san Kent ◽

Ming-forTong Tony ◽

Lam Tak-sum Stephen

Keyword(s):

Muscular Dystrophy ◽

Gene Mutations ◽

Becker Muscular Dystrophy ◽

Chinese Patients ◽

Dmd Gene

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Pathological evaluation of rats carrying in-frame mutations in the dystrophin gene: a new model of Becker muscular dystrophy

Disease Models & Mechanisms ◽

10.1242/dmm.044701 ◽

2020 ◽

Vol 13 (9) ◽

pp. dmm044701

Author(s):

Naomi Teramoto ◽

Hidetoshi Sugihara ◽

Keitaro Yamanouchi ◽

Katsuyuki Nakamura ◽

Koichi Kimura ◽

...

Keyword(s):

Muscular Dystrophy ◽

Gene Mutations ◽

Dystrophin Gene ◽

Becker Muscular Dystrophy ◽

Severe Form ◽

Independent Manner ◽

Glycoprotein Complex ◽

Dystrophin Expression ◽

Pathological Evaluation ◽

Dystrophin Glycoprotein Complex

ABSTRACTDystrophin, encoded by the DMD gene on the X chromosome, stabilizes the sarcolemma by linking the actin cytoskeleton with the dystrophin-glycoprotein complex (DGC). In-frame mutations in DMD cause a milder form of X-linked muscular dystrophy, called Becker muscular dystrophy (BMD), characterized by the reduced expression of truncated dystrophin. So far, no animal model with in-frame mutations in Dmd has been established. As a result, the effect of in-frame mutations on the dystrophin expression profile and disease progression of BMD remains unclear. In this study, we established a novel rat model carrying in-frame Dmd gene mutations (IF rats) and evaluated the pathology. We found that IF rats exhibited reduced expression of truncated dystrophin in a proteasome-independent manner. This abnormal dystrophin expression caused dystrophic changes in muscle tissues but did not lead to functional deficiency. We also found that the expression of additional dystrophin named dpX, which forms the DGC in the sarcolemma, was associated with the appearance of truncated dystrophin. In conclusion, the outcomes of this study contribute to the further understanding of BMD pathology and help elucidate the efficiency of dystrophin recovery treatments in Duchenne muscular dystrophy, a more severe form of X-linked muscular dystrophy.

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Gestational Outcomes of Pregnant Women Who Have Had Invasive Prenatal Testing for the Prenatal Diagnosis of Duchenne Muscular Dystrophy

Journal of Pregnancy ◽

10.1155/2018/9718316 ◽

2018 ◽

Vol 2018 ◽

pp. 1-5

Author(s):

Mehmet Sinan Beksac ◽

Atakan Tanacan ◽

Duygu Aydin Hakli ◽

Gokcen Orgul ◽

Burcu Soyak ◽

...

Keyword(s):

Prenatal Diagnosis ◽

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Chorionic Villus ◽

Gene Mutations ◽

Diagnostic Methods ◽

Obstetric Outcomes ◽

Chorionic Villus Sampling ◽

Significant Difference ◽

Dmd Gene

Aim. To show the importance of prenatal diagnosis of Duchenne Muscular Dystrophy (DMD) and to demonstrate the effect of DMD gene mutations on gestational outcomes. Materials and Methods. We retrospectively evaluated 89 pregnancies in 81 individuals who were referred to Hacettepe University for prenatal diagnosis of DMD between January 2000 and December 2015. Prenatal diagnostic methods (chorionic villus sampling (CVS): 66, amniocentesis (AC): 23) were compared for test results, demographic features, and obstetric outcomes of pregnancies. The female fetuses were divided into two groups according to the DMD status (healthy or carrier) to understand the effect of DMD gene mutations on obstetric outcomes. Results. Eight prenatally diagnosed disease-positive fetuses were terminated. There was no statistically significant difference between the CVS and AC groups in terms of study variables. There were 46 male fetuses (51.6%) and 43 female fetuses (48.4%). Fifteen of the female fetuses were carriers (34.8%). Median birthweight values were statistically insignificantly lower in the carrier group. Conclusion. Pregnancies at risk for DMD should be prenatally tested to prevent the effect of disease on families and DMD carrier fetuses had obstetric outcomes similar to DMD negative female fetuses.

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Duchenne and Becker Muscular Dystrophy: Contribution of a Molecular and Immunohistochemical Analysis in Diagnosis in Morocco

Journal of Biomedicine and Biotechnology ◽

10.1155/2009/325210 ◽

2009 ◽

Vol 2009 ◽

pp. 1-5 ◽

Cited By ~ 8

Author(s):

Hanane Bellayou ◽

Khalil Hamzi ◽

Mohamed Abdou Rafai ◽

Mehdi Karkouri ◽

Ilham Slassi ◽

...

Keyword(s):

Muscular Dystrophy ◽

Genetic Analysis ◽

Immunohistochemical Staining ◽

Correct Diagnosis ◽

Immunohistochemical Analysis ◽

Dystrophin Gene ◽

Becker Muscular Dystrophy ◽

Pcr Multiplex ◽

Dmd Gene ◽

Recessive Disorders

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are X-linked recessive disorders caused by mutations of the DMD gene located at Xp21. In DMD patients, dystrophin is virtually absent; whereas BMD patients have 10% to 40% of the normal amount. Deletions in the dystrophin gene represent 65% of mutations in DMD/BMD patients. To explain the contribution of immunohistochemical and genetic analysis in the diagnosis of these dystrophies, we present 10 cases of DMD/BMD with particular features. We have analyzed the patients with immunohistochemical staining and PCR multiplex to screen for exons deletions. Determination of the quantity and distribution of dystrophin by immunohistochemical staining can confirm the presence of dystrophinopathy and allows differentiation between DMD and BMD, but dystrophin staining is not always conclusive in BMD. Therefore, only identification involved mutation by genetic analysis can establish a correct diagnosis.

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