A population-based study of dystrophin mutations in Canada

Introduction: We carried out a population-based study of dystrophin mutations in patients followed by members of the Canadian Paediatric Neuromuscular Group (CPNG) over a ten-year period. Objectives: We aimed to describe the changes in diagnostic testing for dystrophinopathy and to determine the frequency of dystrophin mutations from 2000 to 2009. Methods: De-identified data containing the clinical phenotypes, diagnostic methods, and mutational reports from dystrophinopathy patients followed by CPNG centres from January 2000 to December 2009 were analyzed using descriptive statistics. Results: 773 patients had a confirmed diagnosis of dystrophinopathy based on genetic testing (97%), muscle biopsy (2%), or family history (1%). 573 (74%) had complete deletion/duplication analysis of all 79 exons or whole gene sequencing, resulting in 366 (64%) deletions, 64 (11%) duplications, and 143 (25%) point mutations. The percentage of patients who were diagnosed using currently accepted genetic testing methods varied across Canada, with a mean of 63% (SD 23). 246 (43%) mutations involved exons 45 to 53. The top ten deletions (n=147, 26%) were exons 45-47, 45-48, 45, 45-50, 45-55, 51, 45-49, 45-52, 49-50, and 46-47. 169 (29%) mutations involved exons 2 to 20. The most common duplications (n=29, 5.1%) were exons 2, 2-7, 2-17, 3-7, 8-11, 10, 10-11, and 12. Conclusion: This is the most comprehensive report of dystrophin mutations in Canada. Consensus guidelines regarding the diagnostic approach to dystrophinopathy will hopefully reduce the geographical variation in mutation detection rates in the coming decade

Establishing a core outcome set for peritoneal dialysis : report of the SONG-PD (standardized outcomes in nephrology-peritoneal dialysis) consensus workshop

Outcomes reported in randomized controlled trials in peritoneal dialysis (PD) are diverse, are measured inconsistently, and may not be important to patients, families, and clinicians. The Standardized Outcomes in Nephrology-Peritoneal Dialysis (SONG-PD) initiative aims to establish a core outcome set for trials in PD based on the shared priorities of all stakeholders. We convened an international SONG-PD stakeholder consensus workshop in May 2018 in Vancouver, Canada. Nineteen patients/caregivers and 51 health professionals attended. Participants discussed core outcome domains and implementation in trials in PD. Four themes relating to the formation of core outcome domains were identified: life participation as a main goal of PD, impact of fatigue, empowerment for preparation and planning, and separation of contributing factors from core factors. Considerations for implementation were identified: standardizing patient-reported outcomes, requiring a validated and feasible measure, simplicity of binary outcomes, responsiveness to interventions, and using positive terminology. All stakeholders supported inclusion of PD-related infection, cardiovascular disease, mortality, technique survival, and life participation as the core outcome domains for PD

Danon disease due to a novel splice mutation in the LAMP2 gene

Danon disease is a rare X-linked dominant disorder caused by lysosomal-associated membrane protein 2 (LAMP2) deficiency and is characterized by hypertrophic cardiomyopathy, cardiac conduction abnormalities, skeletal vacuolar myopathy, variable degree of mental retardation, and peripheral pigmentary retinopathy. We describe a novel splice mutation in the LAMP2 gene in a French Canadian family. By identifying this novel mutation we were able to offer genetic screening and counseling to all family members. Presymptomatic diagnosis is important as cardiac surveillance can be life-saving

A newborn with spinal muscular atrophy type 0 presenting with a clinicopathological picture suggestive of myotubular myopathy.

We report a male term newborn with genetically confirmed spinal muscular atrophy type 0, presenting with arthrogryposis and severe generalized weakness and requiring ventilatory support. Muscle biopsy revealed fibers with central nuclei resembling myotubes and negative myotubularin immunohistochemical staining compared with a control muscle biopsy. The absence of myotubularin associated with survival motor neuron protein deficiency suggests that survival motor neuron protein may have a role in muscle fiber maturation and myotubularin expression. Studying the pathology of this rare and lethal neonatal form of spinal muscular atrophy may further our understanding of spinal muscular atrophy pathogenesis

Additional file 1: of Diagnosis of late-onset Pompe disease and other muscle disorders by next-generation sequencing

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