scholarly journals Candidate gene modifiers of dystrophinopathy identified by the uniform application of genome-wide datasets to novel GWAS-identified loci

Author(s):  
Kevin M Flanigan ◽  
Megan A. Waldrop ◽  
Paul T. Martin ◽  
Roxane Alles ◽  
Diane M. Dunn ◽  
...  

Although the major determinant of disease severity in patients with severe Duchenne muscular dystrophy (DMD) or milder Becker muscular dystrophy (BMD) is whether their dystrophin gene (DMD) mutation disrupts the mRNA reading frame or allows expression of a partially functional protein, other genes have been proposed or demonstrated to modify the severity of disease progression. In a companion paper to this one, we describe our novel approaches to genome-wide association study (GWAS) of loss of ambulation (LOA) in the largest genome-wide search to date for loci influencing disease severity in DMD patients. Candidate regulatory SNPs that modify disease progression were identified using an evidential statistical paradigm and here we present a uniform application of recent functional genomic datasets to explore the potential functional impact of the top six candidate regions with PPLD scores of ≥0.4. The results of this analysis of the largest DMD GWAS survey to date elucidate recurrent and potentially new pathways for intervention in the dystrophinopathies.

2010 ◽  
Vol 1 (1) ◽  
pp. 8 ◽  
Author(s):  
Melinda F. Davis ◽  
Katalin H. Scherer ◽  
Timothy M. Miller ◽  
F. John Meaney

Medical investigations use a wide variety of outcome indicators that are often not comparable. It can be challenging to integrate results across multiple studies that do not share a common metric. Some conditions such as Duchenne and Becker muscular dystrophy have a predictable course of disease progression. Severity can be inferred from a patient's medical history. This paper describes the development of a disease severity measure using common markers of disease progression. Rasch modeling was used to estimate severity using dichotomous events that indicate disease progression. Caregivers of 34 young men with Duchenne or Becker muscular dystrophy completed structured interviews about their care and medical history. Interview questions included surgeries (tendon release, scoliosis, tracheostomy), respiratory equipment (assisted ventilation, cough assist devices), and the use of other medical equipment (e.g., braces, walkers, wheelchairs, transfer boards, hospital beds). The resulting measure had a reliability of .83. The correlation between the severity measure and the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) was .68. Preliminary results and item calibrations are provided for the severity measure that can be estimated from caregiver reports or administrative data. DOI:10.2458/azu_jmmss_v1i1_davis


Author(s):  
Melinda F. Davis ◽  
Katalin H. Scherer ◽  
Timothy M. Miller ◽  
F. John Meaney

Medical investigations use a wide variety of outcome indicators that are often not comparable. It can be challenging to integrate results across multiple studies that do not share a common metric. Some conditions such as Duchenne and Becker muscular dystrophy have a predictable course of disease progression. Severity can be inferred from a patient's medical history. This paper describes the development of a disease severity measure using common markers of disease progression. Rasch modeling was used to estimate severity using dichotomous events that indicate disease progression. Caregivers of 34 young men with Duchenne or Becker muscular dystrophy completed structured interviews about their care and medical history. Interview questions included surgeries (tendon release, scoliosis, tracheostomy), respiratory equipment (assisted ventilation, cough assist devices), and the use of other medical equipment (e.g., braces, walkers, wheelchairs, transfer boards, hospital beds). The resulting measure had a reliability of .83. The correlation between the severity measure and the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) was .68. Preliminary results and item calibrations are provided for the severity measure that can be estimated from caregiver reports or administrative data. DOI:10.2458/azu_jmmss_v1i1_davis


Author(s):  
Melinda F. Davis ◽  
Katalin H. Scherer ◽  
Timothy M. Miller ◽  
F. John Meaney

Medical investigations use a wide variety of outcome indicators that are often not comparable. It can be challenging to integrate results across multiple studies that do not share a common metric. Some conditions such as Duchenne and Becker muscular dystrophy have a predictable course of disease progression. Severity can be inferred from a patient's medical history. This paper describes the development of a disease severity measure using common markers of disease progression. Rasch modeling was used to estimate severity using dichotomous events that indicate disease progression. Caregivers of 34 young men with Duchenne or Becker muscular dystrophy completed structured interviews about their care and medical history. Interview questions included surgeries (tendon release, scoliosis, tracheostomy), respiratory equipment (assisted ventilation, cough assist devices), and the use of other medical equipment (e.g., braces, walkers, wheelchairs, transfer boards, hospital beds). The resulting measure had a reliability of .83. The correlation between the severity measure and the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) was .68. Preliminary results and item calibrations are provided for the severity measure that can be estimated from caregiver reports or administrative data. DOI:10.2458/azu_jmmss_v1i1_davis


2010 ◽  
Vol 1 (1) ◽  
pp. 8 ◽  
Author(s):  
Melinda F. Davis ◽  
Katalin H. Scherer ◽  
Timothy M. Miller ◽  
F. John Meaney

Medical investigations use a wide variety of outcome indicators that are often not comparable. It can be challenging to integrate results across multiple studies that do not share a common metric. Some conditions such as Duchenne and Becker muscular dystrophy have a predictable course of disease progression. Severity can be inferred from a patient's medical history. This paper describes the development of a disease severity measure using common markers of disease progression. Rasch modeling was used to estimate severity using dichotomous events that indicate disease progression. Caregivers of 34 young men with Duchenne or Becker muscular dystrophy completed structured interviews about their care and medical history. Interview questions included surgeries (tendon release, scoliosis, tracheostomy), respiratory equipment (assisted ventilation, cough assist devices), and the use of other medical equipment (e.g., braces, walkers, wheelchairs, transfer boards, hospital beds). The resulting measure had a reliability of .83. The correlation between the severity measure and the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) was .68. Preliminary results and item calibrations are provided for the severity measure that can be estimated from caregiver reports or administrative data. DOI:10.2458/azu_jmmss_v1i1_davis


Author(s):  
Vratko Himič ◽  
Kay E. Davies

AbstractDuchenne muscular dystrophy (DMD) is an X-linked progressive muscle-wasting disorder that is caused by a lack of functional dystrophin, a cytoplasmic protein necessary for the structural integrity of muscle. As variants in the dystrophin gene lead to a disruption of the reading frame, pharmacological treatments have only limited efficacy; there is currently no effective therapy and consequently, a significant unmet clinical need for DMD. Recently, novel genetic approaches have shown real promise in treating DMD, with advancements in the efficacy and tropism of exon skipping and surrogate gene therapy. CRISPR-Cas9 has the potential to be a ‘one-hit’ curative treatment in the coming decade. The current limitations of gene editing, such as off-target effects and immunogenicity, are in fact partly constraints of the delivery method itself, and thus research focus has shifted to improving the viral vector. In order to halt the loss of ambulation, early diagnosis and treatment will be pivotal. In an era where genetic sequencing is increasingly utilised in the clinic, genetic therapies will play a progressively central role in DMD therapy. This review delineates the relative merits of cutting-edge genetic approaches, as well as the challenges that still need to be overcome before they become clinically viable.


2019 ◽  
Vol 8 ◽  
pp. 204800401987958
Author(s):  
HR Spaulding ◽  
C Ballmann ◽  
JC Quindry ◽  
MB Hudson ◽  
JT Selsby

Background Duchenne muscular dystrophy is a muscle wasting disease caused by dystrophin gene mutations resulting in dysfunctional dystrophin protein. Autophagy, a proteolytic process, is impaired in dystrophic skeletal muscle though little is known about the effect of dystrophin deficiency on autophagy in cardiac muscle. We hypothesized that with disease progression autophagy would become increasingly dysfunctional based upon indirect autophagic markers. Methods Markers of autophagy were measured by western blot in 7-week-old and 17-month-old control (C57) and dystrophic (mdx) hearts. Results Counter to our hypothesis, markers of autophagy were similar between groups. Given these surprising results, two independent experiments were conducted using 14-month-old mdx mice or 10-month-old mdx/Utrn± mice, a more severe model of Duchenne muscular dystrophy. Data from these animals suggest increased autophagosome degradation. Conclusion Together these data suggest that autophagy is not impaired in the dystrophic myocardium as it is in dystrophic skeletal muscle and that disease progression and related injury is independent of autophagic dysfunction.


2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Alex Gyftopoulos ◽  
Tamara Ashvetiya ◽  
Yi-Ju Chen ◽  
Libin Wang ◽  
Charles H Williams ◽  
...  

Nonischemic dilated cardiomyopathy (DCM) often has a genetic etiology, however, its prevalence and etiologies are not completely understood. The UK Biobank comprises clinical and genetic data for greater than 500,000 individuals with enrollees 40-69 years of age. Our group created a custom phenotype of heart failure using ICD-10 codes for several subtypes of heart failure diagnoses including DCM. We then compared the individuals included in the custom heart failure phenotype to control individuals in a 20-to-1 fashion to identify genetic differences. Data were compared using Mixed Model Analysis for Pedigrees/Populations (MMAP) mixed-model regression. We identified 8 unlinked intronic variants in the dystrophin gene ( DMD ) that, when separated by self-identified race, occurred with a combined minor allele frequency of 0.15 in individuals with heart failure who identified as being of African descent. The combined minor allele frequency of these variants was 0.05 in individuals who self-identified as being of European descent. One variant of DMD in particular (rs139029250), was identified with a minor allele frequency of 0.05 in African British with DCM. The unadjusted odds ratio of a diagnosis of heart failure in individuals with rs129029250 was 4.65. When separated by gender, the unadjusted odds ratios are 2.02 for females and 6.44 for males. DMD is most notably known for its role in Duchenne and Becker muscular dystrophy, both of which are known to cause dilated cardiomyopathy in affected individuals. However, none of the individuals (36 female and 43 male) identified in our analysis with rs129029250 have been diagnosed with Duchenne muscular dystrophy, Becker muscular dystrophy, or a primary disorder of muscle (ICD code G70). Additionally, these individuals have an intronic variant of DMD , while Duchene and Becker muscular dystrophy are both due to exonic mutations. These findings suggest a possible common variant in the DMD gene that may contribute to DCM in individuals of African descent.


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