Identification of a novel DMD duplication identified by a combination of MLPA and targeted exome sequencing

Fertility Does Not Alter Disease Progression in ALS Patients of Childbearing Age: A Three Centers Retrospective Analysis in Southern China

Background

Limited data exists on the clinical features of patients with amyotrophic lateral sclerosis (ALS) during reproductive ages.

Objective

Our study characterized the clinical features of ALS and the effects of pregnancy on disease progression in patients with ALS.

Methods

We performed a retrospective study of female patients with ALS in three ALS research centers in southern China from 2009 to 2021. Data regarding fertility status, and clinical and genetic features, were collected. Age-matched male patients with ALS served as controls. The patients were divided into the following two subgroups: patients with symptom onset within 1 year of pregnancy and patients with symptom onset over 1 year group after pregnancy.

Results

A total of 52 female and 52 matched male patients were enrolled. There were no differences in female and male patients in the mean age of symptom onset, the mean baseline ALSFRS-R score, or median reduction of ALSFRS-R score (p > 0.05). The mean age of first pregnancy was 25.57 ± 4.40) years. The mean age of first pregnancy in the over 1 year group was lower than that in the within 1 year group (p= 0.01). There was no difference in the median reduction of ALSFRS-R between the two subgroups. In the univariate analysis, diagnostic delay was highly correlated with the disease progression, with short delay representing rapid progress. No multicollinearity was found among every variable. In addition, 40.38% patients carried ALS-related gene variants. The proportion with gene mutations in the within 1 year group was higher than that in the over 1 year group (p < 0.01). Furthermore, SETX was the most frequently mutated gene in this cohort (16.67%) including 4 uncertain mutation.

Conclusion

Pregnancy and fertility were not associated with disease progression. Diagnostic delay was correlated with disease progression in this cohort. In addition, SETX might be a gene of concern for ALS patients of childbearing age.

Molecular Diagnosis of Muscular Dystrophy Patients in Western Indian Population: A Comprehensive Mutation Analysis Using Amplicon Sequencing

Muscular Dystrophies (MDs) are a group of inherited diseases and heterogeneous in nature. To date, 40 different genes have been reported for the occurrence and/or progression of MDs. This study was conducted to demonstrate the application of next-generation sequencing (NGS) in developing a time-saving and cost-effective diagnostic method to detect single nucleotide variants (SNVs) and copy number variants (CNVs) in a single test. A total of 123 cases clinically suspected of MD were enrolled in this study. Amplicon panel-based diagnosis was carried out for 102 (DMD/BMD) cases and the results were further screened using multiplex ligation-dependent probe amplification (MLPA). Whilst in the case of LGMD (N = 19) and UMD (N = 2), only NGS panel-based analysis was carried out. We identified the large deletions in 74.50% (76/102) of the cases screened with query DMD or BMD. Further, the large deletion in CAPN3 gene (N = 3) and known SNV mutations (N = 4) were identified in LGMD patients. Together, the total diagnosis rate for this amplicon panel was 70.73% (87/123) which demonstrated the utility of panel-based diagnosis for high throughput, affordable, and time-saving diagnostic strategy. Collectively, present study demonstrates that the panel based NGS sequencing could be superior over to MLPA.

Prenatal diagnosis of de novo DMD duplication by multiplex ligation-dependent probe amplification (MLPA) after noninvasive prenatal screening (NIPS) at 11 gestational weeks

OBJECTIVE

Dystrophinopathy is an X-linked recessive muscular dystrophy caused by mutations in the DMD gene. Herein we describe the prenatal detection of DMD gene mutations in a patient with no family history, by multiplex ligation-dependent probe amplification (MLPA) after noninvasive prenatal screening (NIPS).

CASE REPORT

A 41-year-old woman underwent NIPS owing to an advanced maternal age. A copy number variation was detected in the maternal X chromosome, and uninformative results were obtained for the fetal sex chromosomes. Following amniocentesis, a duplication was identified in exons 1-29 of the dystrophin gene by MLPA. After interviewing her family members it was confirmed that the patient is a de novo carrier of DMD duplications, and her daughter is a carrier of the same mutation.

CONCLUSION

his is the first case report to describe the prenatal diagnosis of duplications in the DMD gene by MLPA following NIPS in a patient with no family history.

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

BACKGROUND

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.

OBJECTIVE

The objective of this study was to analyze the genetic defect of a Chinese family where all male patients have died of DMD.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Mutation spectrum analysis of Duchenne/Becker muscular dystrophy in 68 families in Kuwait: The era of personalized medicine

Duchenne and Becker muscular dystrophies (DMD/BMD) are X-linked recessive neuromuscular disorders characterized by progressive irreversible muscle weakness and atrophy that affect both skeletal and cardiac muscles. DMD/BMD is caused by mutations in the Dystrophin gene on the X chromosome, leading to the absence of the essential muscle protein Dystrophin in DMD. In BMD, Dystrophin is partially functioning with a shorter protein product. Recent advances in molecular therapies for DMD require precise genetic diagnoses because most therapeutic strategies are mutation-specific. Hence, early diagnosis is crucial to allow appropriate planning for patient care and treatment. In this study, data from DMD/BMD patients who attended the Kuwait Medical Genetic Center during the last 20 years was retrieved from a Kuwait neuromuscular registry and analyzed. We combined multiplex PCR and multiplex ligation-dependent probe amplification (MLPA) with Sanger sequencing to detect Dystrophin gene mutations. A total of 35 different large rearrangements, 2 deletion-insertions (Indels) and 4 substitution mutations were identified in the 68 unrelated families. The deletion and duplication rates were 66.2% and 4.4%, respectively. The analyzed data from our registry revealed that 11 (16%) of the DMD families will benefit from newly introduced therapies (Ataluren and exon 51 skipping). At the time of submitting this paper, two cases have already enrolled in Ataluren (Tranlsarna™) therapy, and one case has been enrolled in exon 51 skipping therapy.