Duchenne Muscular Dystrophy Families Research Articles

A female patient carrying a novel DMD mutation with non-random X-chromosome inactivation from a DMD family

ObjectiveTo analyze the clinical phenotype and genetic characteristics of a female proband carrying a novel mutation in the DMD gene with non-random X-chromosome inactivation in a large pedigree with pseudohypertrophic muscular dystrophy.MethodsClinical information of the female proband, her monozygotic twin sister, and other family members were collected. Potential pathogenic variants were detected with Multiplex Ligation-dependent Probe Amplification (MLPA) and whole-exome sequencing (WES). Methylation-sensitive restriction enzyme (HhaI) was employed for X-chromosome inactivation analysis.ResultsThe proband was a female over 5 years old, displayed clinical manifestations such as elevated creatine kinase (CK) levels and mild calf muscle hypertrophy. Her monozygotic twin sister exhibited normal CK levels and motor ability. Her uncle and cousin had a history of DMD. WES revealed that the proband carried a novel variant in the DMD (OMIM: 300,377) gene: NM_004006.3: c.3051_3053dup; NP_003997.2: p.Tyr1018*. In this pedigree, five out of six female members were carriers of this variant, while the cousin and uncle were hemizygous for this variant. X-chromosome inactivation analysis suggested non-random inactivation in the proband.ConclusionThe c.3051_3053dup (p.Tyr1018*) variant in the DMD gene is considered to be the pathogenic variant significantly associated with the clinical phenotype of the proband, her cousin, and her uncle within this family. Integrating genetic testing with clinical phenotype assessment can be a valuable tool for physicians in the diagnosis of progressive muscular dystrophies, such as Becker muscular dystrophy (BMD) and Duchenne muscular dystrophy (DMD).

The impact of clinical trial participation on quality of life and psychosocial well-being in children with Duchenne muscular dystrophy and their parents

Clinical trials provide Duchenne muscular dystrophy (DMD) patients access to medication. Nevertheless, such involvement can impose certain burdens, as the protocol may entail strict adherence and additional demands. This study assessed the psychosocial functioning and quality of life in boys with DMD and their parents who participate in clinical trials. DMD families participating in clinical trials (n = 25) and families with DMD patients not involved in clinical trials (N = 18) were included. Questionnaires assessing psychosocial well-being and quality of life were completed by the participants and their parents. MANOVAs were employed to compare outcomes between groups. The results showed that mothers in the clinical trial group experienced significantly higher scores of somatic complaints. Fathers in the clinical trial group reported significantly fewer psychological issues compared to fathers from the other group. DMD patients participating in clinical trials reported a better overall and emotional quality of life compared to them not involved in clinical trials. This study suggests that clinical trial participation may have positive effects on quality of life and psychosocial outcomes. It highlights the importance of providing support and counseling throughout the clinical trial decision making process to minimize potential burden for both eligible and ineligible patients.

Clinical, muscle imaging, and genetic characteristics of dystrophinopathies with deep-intronic DMD variants.

Phenotypic heterogeneity within or between families with a same deep-intronic splice-altering variant in the DMD gene has never been systematically analyzed. This study aimed to determine the phenotypic and genetic characteristics of patients with deep-intronic DMD variants. Of 1338 male patients with a suspected dystrophinopathy, 38 were confirmed to have atypical pathogenic DMD variants via our comprehensive genetic testing approach. Of the 38 patients, 30 patients from 22 unrelated families with deep-intronic DMD variants underwent a detailed clinical and imaging assessment. Nineteen different deep-intronic DMD variants were identified in the 30 patients, including 15 with Duchenne muscular dystrophy (DMD), 14 with Becker muscular dystrophy (BMD), and one with X-linked dilated cardiomyopathy. Of the 19 variants, 15 were single-nucleotide variants, 2 were structural variants (SVs), and 2 were pure-intronic large-scale SVs causing aberrant inclusion of other protein-coding genes sequences into the mature DMD transcripts. The trefoil with single fruit sign was observed in 18 patients and the concentric fatty infiltration pattern was observed in 2 patients. Remarkable phenotypic heterogeneity was observed not only in skeletal but also cardiac muscle involvement in 2 families harboring a same deep-intronic variant. Different skeletal muscle involvement between families with a same variant was observed in 4 families. High inter-individual phenotypic heterogeneity was observed within two BMD families and one DMD family. Our study first highlights the variable phenotypic expressivity of deep-intronic DMD variants and demonstrates a new class of deep-intronic DMD variants, i.e., pure-intronic SVs involving other protein-coding genes.

A Parent-Focused Survey to Assess the Effects of the COVID-19 Pandemic on Patients With Duchenne Muscular Dystrophy

The aim of this study was to evaluate the effect of the Coronavirus Disease (COVID-19) on the use of health and rehabilitation services, physical and general health conditions of individuals with Duchenne Muscular Dystrophy (DMD) from the perspective of parents. A questionnaire consisting of 35 questions was created by the research team. The data were obtained from the parents/primary caregivers of individuals whose diagnoses were confirmed by genetic testing and accessed online via the DMD Families Association. It was reported that 5.5% of the 272 individuals with DMD (age: 10.43±6.42 years) included in the study were infected with COVID-19. It was observed that the major problems encountered during the pandemic were obtaining health services (81%) and stress management (42%). More than half of the individuals were found to be adversely affected in general health (52%), mobility (56%), range of motion (54%), mood (66%), and social dialogs (62%). Furthermore, it was determined that 71% of the individuals took a break from the center where they received outpatient physiotherapy for 3 months or more, and only 6% could receive telerehabilitation service and the level of satisfaction was relatively moderate (10-point visual analog scale: 6.3±2.6). The parents reported that the health care utilization and physical-general health status of individuals with DMD were significantly adversely affected during the COVID-19 pandemic. The present study has an exploratory feature regarding the problems faced by individuals with DMD during the COVID-19 pandemic. Therefore, we think that it will guide future studies in preventing the negative effects of situations such as pandemics or natural disasters.

Morbidity, Clinical Course and Vaccination against SARS-CoV-2 Virus in Patients with Duchenne Muscular Dystrophy: A Patient Reported Survey.

Background: Patients with Duchenne muscular dystrophy (DMD) may be at higher risk of a severe course of COVID-19. The aim of the study was to evaluate: (1) the incidence and course of COVID-19 infection in DMD patients; (2) the vaccination status of DMD patients; and (3) COVID-19 related anxiety among DMD families. Materials and Methods: The study was conducted during an online symposium for DMD patients and their families. All participants (DMD families; n = 150) were asked to fill in the online survey with questions about COVID-19 infection history, vaccination against SARS-CoV-2 and anxiety during pandemic. Results: 53 DMD patients filled in the survey. Five (9.43%) were COVID-19 positive with mild symptoms of respiratory infection and anosmia; 23 (42.6%) were vaccinated, but in almost 20% of DMD families, none of the family members was vaccinated. Respondents revealed anxiety related both to the vaccination procedure and to COVID-19 infection (complications after infection 93.6%, death 62.4% respondents). Changes in health care system organization also aroused concern among participants (85.3%). Conclusion: The course of the COVID-19 infection in DMD patients was mild. Not enough patients with DMD and their families are vaccinated. Education about the management of COVID-19 infections and the vaccination procedure for DMD patients is needed and expected.

Haplotype-Based Noninvasive Prenatal Diagnosis of 21 Families With Duchenne Muscular Dystrophy: Real-World Clinical Data in China.

Noninvasive prenatal diagnosis (NIPD) of single-gene disorders has recently become the focus of clinical laboratories. However, reports on the clinical application of NIPD of Duchenne muscular dystrophy (DMD) are limited. This study aimed to evaluate the detection performance of haplotype-based NIPD of DMD in a real clinical environment. Twenty-one DMD families at 7–12 weeks of gestation were prospectively recruited. DNA libraries of cell-free DNA from the pregnant and genomic DNA from family members were captured using a custom assay for the enrichment of DMD gene exons and spanning single-nucleotide polymorphisms, followed by next-generation sequencing. Parental haplotype phasing was based on family linkage analysis, and fetal genotyping was inferred using the Bayes factor through target maternal plasma sequencing. Finally, the entire experimental process was promoted in the local clinical laboratory. We recruited 13 complete families, 6 families without paternal samples, and 2 families without probands in which daughter samples were collected. Two different maternal haplotypes were constructed based on family members in all 21 pedigrees at as early as 7 gestational weeks. Among the included families, the fetal genotypes of 20 families were identified at the first blood collection, and a second blood collection was performed for another family due to low fetal concentration. The NIPD result of each family was reported within 1 week. The fetal fraction in maternal cfDNA ranged from 1.87 to 11.68%. In addition, recombination events were assessed in two fetuses. All NIPD results were concordant with the findings of invasive prenatal diagnosis (chorionic villus sampling or amniocentesis). Exon capture and haplotype-based NIPD of DMD are regularly used for DMD genetic diagnosis, carrier screening, and noninvasive prenatal diagnosis in the clinic. Our method, haplotype-based early screening for DMD fetal genotyping via cfDNA sequencing, has high feasibility and accuracy, a short turnaround time, and is inexpensive in a real clinical environment.

Noninvasive prenatal diagnosis of duchenne muscular dystrophy in five Chinese families based on relative mutation dosage approach

BackgroundRelative haplotype dosage (RHDO) approach has been applied in noninvasive prenatal diagnosis (NIPD) of Duchenne muscular dystrophy (DMD). However, the RHDO procedure is relatively complicated and the parental haplotypes need to be constructed. Furthermore, it is not suitable for the diagnosis of de novo mutations or mosaicism in germ cells. Here, we investigated NIPD of DMD using a relative mutation dosage (RMD)-based approach—cell-free DNA Barcode-Enabled Single-Molecule Test (cfBEST), which has not previously been applied in the diagnosis of exon deletion.MethodsFive DMD families caused by DMD gene point mutations or exon deletion were recruited for this study. After the breakpoints of exon deletion were precisely mapped with multiple PCR, the genotypes of the fetuses from the five DMD families were inferred using cfBEST, and were further validated by invasive prenatal diagnosis.ResultsThe cfBEST results of the five families indicated that one fetus was female and did not carry the familial molecular alteration, three fetuses were carriers and one was male without the familial mutation. The invasive prenatal diagnosis results were consistent with those of the cfBEST procedure.ConclusionThis is the first report of NIPD of DMD using the RMD-based approach. We extended the application of cfBEST from point mutation to exon deletion mutation. The results showed that cfBEST would be suitable for NIPD of DMD caused by different kinds of mutation types.

Prediagnosis pathway benchmarking audit in patients with Duchenne muscular dystrophy

ObjectiveTo describe age and time at key stages in the Duchenne muscular dystrophy (DMD) prediagnosis pathway at selected centres to identify opportunities for service improvement.DesignA multicentre retrospective national audit.SettingNine tertiary...

Identification of two rare mutations c.1318G>A and c.6438+2T>G in a Chinese DMD family as genetic markers.

Duchenne muscular dystrophy (DMD) is a fatal X-linked recessive disorder with no effective treatment, which underscores the importance of avoiding the birth of children with DMD by identifying pathogenic mutations and obtaining an accurate prenatal diagnosis. The objective of this study was to analyze the genetic defect of a Chinese family where all male patients have died of DMD. Multiplex ligation dependent probe analysis (MLPA) and next-generation sequencing (NGS) were employed to detect DMD mutations. The candidate mutations were then validated by Sanger sequencing. In vitro splicing assay was further conducted to examine the potential effect of the novel DMD splice site mutation on splicing. We found that two rare DMD mutations c.1318G>A and c.6438+2T>G passed from generation to generation among female carriers and they may be used as genetic markers in the Chinese DMD family. In vitro splicing assay further revealed that the novel classical splice site mutation c.6438+2T>G gave rise to a new donor splice site, which resulted in a frame shift of the transcripts and a premature termination at position 2159 in exon 45 (p.Y2144Nfs*16). We found that two co-inherited mutations passed from generation to generation in female carriers and they may be used as genetic markers in the Chinese DMD family. Our findings not only expanded the DMD mutation spectrum, but also provided an important basis for identifying of female carriers and avoiding the birth of affected male children in this DMD family.

Health-related quality of life in Chinese boys with Duchenne muscular dystrophy and their families.

This study aims to assess the family functioning and health-related quality of life (HRQOL) in Chinese boys with Duchenne muscular dystrophy (DMD) and their parents using Pediatric Quality-of-Life Family Impact Module (PedsQL FIM) and Pediatric Quality-of-Life Inventory (PedsQL) 4.0. Findings from 15 families with DMD were compared with 15 unaffected families. The HRQOL, as measured by the mean PedsQL 4.0 Generic Core Scale scores for the boys with DMD were significantly lower than those of age-matched healthy boys, for overall (p < 0.05, parent-report; p <0.001, self-report), physical (p < 0.001, parent-report and self-report), and social (p < 0.05, parent-report) functioning, but the emotional functioning is not affected. The parent-child concordance of our affected DMD families was generally in the moderate-to-good agreement range (intraclass correlation coefficients from 0.51 to 0.73), except for emotional (0.28) and social (0.31) functioning. The PedsQL FIM total score showed an inverse relationship with the affected child's age (correlation coefficient: -0.55; p < 0.01) and the disease stage (correlation coefficient: -0.63; p < 0.01) confirming that parental HRQOL and overall family functioning worsened as the child increased in age with advancing disease stage.

Targeted linked-read sequencing for direct haplotype phasing of maternal DMD alleles: a practical and reliable method for noninvasive prenatal diagnosis

For the noninvasive prenatal diagnosis (NIPD) of X-linked recessive diseases such as Duchenne muscular dystrophy (DMD), maternal haplotype phasing is a critical step for dosage analysis of the inherited allele. Until recently, the proband-based indirect haplotyping method has been preferred despite its limitations for use in clinical practice. Here, we describe a method for directly determining the maternal haplotype without requiring the proband’s DNA in DMD families. We used targeted linked-read deep sequencing (mean coverage of 692×) of gDNA from 5 mothers to resolve their haplotypes and predict the mutation status of the fetus. The haplotype of DMD alleles in the carrier mother was successfully phased through a targeted linked-read sequencing platform. Compared with the proband-based phasing method, linked-read sequencing was more accurate in differentiating whether the recombination events occurred in the proband or in the fetus. The predicted inheritance of the DMD mutation was diagnosed correctly in all 5 families in which the mutation had been confirmed using amniocentesis or chorionic villus sampling. Direct haplotyping by this targeted linked-read sequencing method could be used as a phasing method for the NIPD of DMD, especially when the genomic DNA of the proband is unavailable.

A retrospective analysis of 237 Chinese families with Duchenne muscular dystrophy history and strategies of prenatal diagnosis.

To offer 4-year clinical prenatal diagnosis experience of Duchenne muscular dystrophy (DMD). Denaturing high-performance liquid chromatography (DHPLC) and Sanger sequencing were used for molecular diagnosis of 237 DMD families. In the study, deletions, duplications, complex rearrangement and small mutations accounted for 47.3%, 8.4%, 1.7% and 42.6% of 237 families, respectively. Sixty-six different deletion patterns were identified in 112 families. Fourteen different duplication patterns were identified in 20 families and 4 complex rearrangements were identified. About 87.1% different small mutation patterns were identified, including 37.6% different nonsense mutation patterns, 24.8% different frameshift mutation patterns, 7.9% different missense mutation patterns, and 16.8% different splice site mutation patterns. There was no significant difference in the age of onset and mutation patterns (P>.05). The follow-up examinations revealed that the pregnancies of 14 cases were interrupted. Two cases were preterm births, 151 cases were delivered at term, 63 cases continued to pregnancy, and 7 cases were lost to follow-up. DHPLC and Sanger sequencing technique are efficient, sensitive, and specific in screening for DMD gene mutations. And pre-pregnancy DMD gene examination is an important step to assess mutation type of family with suspected DMD and guides exactly prenatal diagnosis in high-risk families.

A comparative study of care practices for young boys with Duchenne muscular dystrophy between Japan and European countries: Implications of early diagnosis

Early diagnosis of Duchenne muscular dystrophy (DMD) is widely advocated to initiate proactive interventions and genetic counselling. Genetic testing now allows the diagnosis of DMD even prior to the onset of symptoms. However, little is known about care practices and their impact on young DMD boys and families after receiving an early diagnosis. We analysed 64 young boys (Japan, 19; the United Kingdom, 10; Germany, 18; Hungary, 6; Poland, 5; and the Czech Republic, 6) aged <5 years and diagnosed at ≤2 years old among the participants of the cross-sectional study about care practice in DMD. A combination of elevated serum creatine kinase and genetic testing usually led to the diagnosis (n = 31, 48%); 41 boys visited neuromuscular clinics more than once a year. Early diagnosis did not generally result in higher satisfaction among DMD families, and country-specific differences were observed. Psychosocial support following early diagnosis was perceived as insufficient in most countries, and deficits in access and uptake of genetic counselling resulted in lower satisfaction in the Japanese cohort. In conclusion, seamless and comprehensive support for DMD families following early diagnosis at presymptomatic stages should be taken into consideration if early genetic testing or newborn screening is made available more widely.

Prenatal diagnosis of Duchenne muscular dystrophy in 131 Chinese families with dystrophinopathy.

The objective of this study is to report 6-year clinical prenatal diagnosis experience of Duchenne muscular dystrophy (DMD)-affected families evaluated at a single prenatal diagnosis center in China and establish a reliable and rational prenatal diagnosis procedure for DMD families. The prenatal diagnosis data of 146 at-risk pregnancies in 131 DMD families referred to our center from 2010 to 2016 were retrospectively reviewed. The mutation detection rate of the probands was greater than 99%. In the 131 families, 50 mothers showed negative results during carrier testing, and de novo exon deletions arose in 51.1% of the probands. Of the 146 pregnancies, 91 were male fetuses, 34 of which were affected. Germline mosaicism was identified three times in this cohort, and recombination of the DMD gene was detected in nine cases. Accurate genetic diagnosis of the proband is important for preventing recurrence in at-risk families. The present results demonstrate the importance of considering maternal germline mosaicism in the genetic assessment. Prenatal diagnosis should be suggested to the parent with a DMD proband whether carrier testing found the causative mutation in the mother's blood or not. Finally, we have developed a prenatal diagnosis algorithm for dystrophinopathies that combines multiplex ligation-dependent probe amplification, quantitative PCR, sequencing and linkage analyses. © 2017 John Wiley & Sons, Ltd.

Splicing mutation of a gene within the Duchenne muscular dystrophy family.

The aim of this study was to identify the mutation site and phenotype of the Duchenne muscular dystrophy (DMD) gene in a DMD family. The DMD gene is by far the largest known gene in humans. Up to 34% of the point mutations reported to date affect splice sites of the DMD gene. However, no hotspot mutation has been reported. Capture sequencing of second-generation exons was used to investigate the DMD gene in a proband. Sanger sequencing was performed for mutation scanning in eight family members. Scale-invariant feature transform and PolyPhen were applied to predict the functional impact of protein mutations. A hemizygous splicing mutation IVS44ds +1G-A (c.6438 +1G>A) that induces abnormal splicing variants during late transcription and produces abnormal proteins was located in intron 44. Four missense mutations (p.Arg2937Gln, p.Asp882Gly, p.Lys2366Gln, and p.Arg1745His) that are known multiple-polymorphic sites were found in the coding region of the DMD gene. A heterozygous c.6438+1G>A mutation was detected on the X chromosome of the proband's mother and maternal grandmother.

Predictors of Family Function in DMD and SMA Family

Introduction: The progressive disability creates a low quality of life for families of children with muscular dystrophy. The families experience family overload, resulting in the alienation of family members and the common occurrence of caregiver burden, and resulting economic burden. Purpose: The purposes of the study were to identify the differences in family characteristics, health needs, lifestyle, and overall family health status between cohorts of families with a child from either Duchenne muscular dystrophy (DMD) or spinal muscular dystrophy (SMA). And analyzed the predictive factors influence the major health-associated variables. Methods: Analyzes were conducted on data derived from 86 of families with DMD or SMA. Participants (113, mean age: 42.68 years) included the patient’s parents, siblings, and other caregivers of children with DMD and SMA. The data were obtained using selfreported questionnaires. Results: The results show that family support, family hardiness, the power to propose an idea/plan, and family incomes are predictors for family functioning. Gender, education, income, time spent watching TV, and the power to propose an idea or plan constituted important characteristics influencing this model of family health and family function. Conclusion: The results of this knowledge are important for development of professional strategies and treatment plans.

Trends With Corticosteroid Use in Males With Duchenne Muscular Dystrophy Born 1982-2001

This study examines trends in corticosteroid use for males with Duchenne muscular dystrophy by birth year, race/ethnicity, and knowledge of Duchenne muscular dystrophy family history. Firstborn males (n = 521) selected from a population-based surveillance system of Duchenne muscular dystrophy were analyzed using Kaplan Meier and regression methods. Comparing males born 1982 to 1986 with males born 1997 to 2001, steroid use increased from 54% to 72% and mean age at steroid initiation decreased from 8.2 to 7.1 years. Hispanics and non-Hispanic Black males used steroids less frequently and delayed initiation compared to white males. Compared to males without a Duchenne muscular dystrophy family history, males with known family history were half as likely to use steroids. Duration of steroid use increased over time and age at initiation decreased. Racial/ethnic disparities exist for steroid use and should be addressed to improve outcome and quality of life for boys with Duchenne muscular dystrophy.

Development of a comprehensive real-time PCR assay for dystrophin gene analysis and prenatal diagnosis of Chinese families

BackgroundTo develop a comprehensive method to analyze deletions or duplications of the dystrophin gene in both patients and carriers of Duchenne muscular dystrophy (DMD), likewise applied to prenatal diagnosis. MethodsA total of thirty Chinese families were recruited, composed of 29 DMD affected males and 38 female relatives containing four pregnant women. Deletions were previously screened by multiplex PCR. A comprehensive real-time PCR assay using SYBR Green I dye was performed for the initial detection of duplications in patients with a seven-exon primer set, carrier detection for female relatives and prenatal diagnosis for the 4 of them. The results were later confirmed by multiple ligation-dependent probe amplification (MLPA) and linkage analysis. ResultsThree out of 4 duplications were first discovered by real-time PCR. Carrier status was ascertained in 22 and rejected in the remaining sixteen female relatives. Furthermore, 4 fetuses were diagnosed as two normal females, one normal male and one female carrier, respectively. ConclusionsOur real-time PCR assay is useful in duplication screen with a detection rate of >70%, as well as rapid and reliable in both carrier detection and prenatal diagnosis of DMD families with known deletions and duplications.

Rehabilitation therapy of Duchenne muscular dystrophy

It is very important that the rehabilitation therapy of Duchenne muscular dystrophy (DMD) can improve the quality of life and delay the disease progression. There are the guidelines for DMD rehabilitation therapy in some countries, but it is not emphasized by clinical doctors in our country. According to our experiences to DMD rehabilitation therapy, we reviewed the progress of DMD rehabilitation therapy. It includes the clinical stages and characteristics of DMD, the general principle and the common therapy methods of DMD rehabilitation. We hope this review may increase recognizing to DMD rehabilitation therapy for the clinical doctors and DMD family members. DOI：10.3969/j.issn.1672⁃6731.2012.03.007

Results of Duchenne muscular dystrophy family screening in practice: leaks rather than cascades?

Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disease caused by mutations in the gene that encodes the protein dystrophin. Approximately 2 of 3 affected boys inherit their mutation from their carrier mother whereupon other female relatives are at risk of carrying the mutation. Female carriers are also at risk of developing cardiomyopathy and regular cardiac screening is recommended. Clinical genetics services offer genetic counselling and carrier tests for consenting relatives of DMD patients known as 'cascade screening'. We retrospectively analysed data from two genetics centres, West of Scotland and South East Thames where the latter centre operated a computer-held DMD register. Over the period, 1971-2008, a total of 843 potential carriers, in 195 West of Scotland families, were tested: 16% of 1st degree relatives and 48% of 2nd degree and more distant relatives were not tested. In South East Thames, a total of 1223 potential carriers in 349 families were tested: 49% of 1st degree and 65% of 2nd degree and more distant relatives were not tested. These data are similar to Becker muscular dystrophy/DMD carrier screening results recently reported from the Netherlands. Retrospective results from three countries indicate that despite efforts to offer extended cascade screening, significant numbers of potential carriers of DMD remain unaware of their reproductive and health risks.