Limb-girdle muscular dystrophy: A perspective from adult patients on what matters most

Health-Related Quality of Life in FKRP-Related Limb-Girdle Muscular Dystrophy R9

BACKGROUND

Limb-girdle muscular dystrophy R9 (LGMDR9) is a chronic progressive hereditary muscle disease, related to the Fukutin Related Protein (FKRP) gene, that may cause major disabilities, cardiomyopathy, and ventilatory failure. Knowledge of how LGMDR9 affects health-related quality of life (HRQoL) is relevant in treatment and care.

OBJECTIVE

To investigate HRQoL in the Norwegian LGMDR9 population over 14 months and relation to fatigue and sleep quality.

METHODS

Participants (16+ years) of the Norwegian LGMDR9 cohort study completed two HRQoL measures, i.e., Individualized Neuromuscular Quality of Life questionnaire (INQoL) and the 36-item Short Form (SF-36) at baseline, 8, and 14 months and measures of fatigue and sleep quality at 9 months.

RESULTS

HRQoL response rate was 84/90 (75 c.826 C > A homozygotes and nine c.826 C > A compound heterozygotes). Compared to Norwegian normative data, all SF-36 domain scores were impaired (p≤0.006) except mental health in males (p = 0.05) and pain scores. During 14 months, perceived muscle weakness and the INQoL index (disease burden) worsened in c.826 C > A homozygotes. Compound heterozygotes reported more dysphagia and physical difficulties than homozygotes and showed a tendency towards worsening in weakness over time but some improvement on the INQoL index. Homozygous females reported generally poorer HRQoL and a higher burden than males. The INQoL index was related to perceived muscle weakness and fatigue, and fatigue to myalgia and mental distress. The prevalence of fatigue and poor sleep was 40% and 49%, respectively.

CONCLUSIONS

The 14-month follow-up period shows a worsening of perceived weakness and burden in c.826 C > A homozygotes, which can then be expected. The prevalence and impact of fatigue indicate a need for awareness and treatment of fatigue. Myalgia and mental distress are potential targets in the treatment of fatigue, which future studies need to establish. Sleep issues and gender-specific care needs also require attention in LGMDR9.

'It becomes the new everyday life' - experiences of chronic pain in everyday life of people with limb-girdle muscular dystrophy

PURPOSE

To investigate experiences and reflections on challenges in everyday life of people living with limb-girdle muscular dystrophy (LGMD) and chronic pain in order to improve rehabilitation services.

MATERIALS AND METHODS

The design for this study was qualitative using the Interpretive Description methodology and the salutogenic theory of Sense of Coherence as the theoretical framework. Four semi-structured focus group interviews were conducted with 19 adults with LGMD from April to May 2021. The interviews were conducted online due to COVID-19.

RESULTS

Living with chronic pain and LGMD affected everyday life in terms of the participants' overall Sense of Coherence. Beneficial or unfavorable coping strategies were identified within four interrelated categorical themes: pain management, normality comprehension, affected emotional sentiment and altered identity.

CONCLUSION

Healthcare professionals should acknowledge possible chronic pain secondary to LGMD. Chronic pain appears to be a prevalent problem in people with LGMD with negative impact on everyday life, yet patients with LGMD did not receive sufficient information and necessary tools from health professionals to cope with chronic pain. Thus, adequate pain management appeared to be a difficult and self-taught process. Educating health professionals on how to support patients with LGMD and chronic pain is needed.IMPLICATIONS FOR REHABILITATIONHealth professionals should acknowledge and address the possibility of chronic pain secondary to limb-girdle muscular dystrophy (LGMD) and educate patients in pain management.Physiotherapy, energy management and engagement in meaningful activities may help patients gain some control of pain and limit the consequences of pain on everyday life.Supporting patients to accept pain and to shift focus towards their current capabilities may potentially improve pain management.Educating health professionals on how to support patients with LGMD and chronic pain is needed.

Limb-Girdle Muscular Dystrophy Type 2B (LGMD2B) caused by Pathogenic Splice and Missense Variants of DYSF Gene among Iranians with Muscular Dystrophy

Background

The phenotypic range of limb-girdle muscular dystrophies (LGMDs) varies significantly because of genetic heterogeneity ranging from very mild to severe forms. Molecular analysis of the DYSF gene is challenging due to the wide range of mutations and associated complications in interpretations of novel DYSF variants with uncertain significance. Thus, in the current study, we performed the NGS analysis and its results are confirmed with Sanger sequencing to find the plausible disease-causing variants in patients with muscular dystrophy and their relatives via segregation analysis.

Materials and Methods

Nine patients with LGMD type 2B (LGMD2B) characteristics were screened for putative mutations by the whole-exome sequencing (WES) test. Either the patients themselves or their parents and first relatives were investigated in the segregation analysis through Sanger sequencing. The majority of variants were classified as pathogenic through American College of Medical Genetics and Genomics (ACMG) guidelines, segregation results, and in silico predictions.

Results

Results revealed eight variants in DYSF gene, including three splicing (c.1149+4A>G, c.2864+1G>A, and c.5785-7G>A), two nonsense (p.Gln112Ter and p.Trp2084Ter), two missense (p.Thr1546Pro and p.Tyr1032Cys), and one frameshift (p.Asp1067Ilefs), among nine Iranian families. One of the eight identified variants was novel, including p.Asp1067Ilefs, which was predicted to be likely pathogenic based on the ACMG guidelines. Notably, prediction tools suggested the damaging effects of studied variants on dysferlin structure.

Conclusion

Conclusively, the current report introduced eight variants including a novel frameshift in DYSF gene with noticeable pathogenic effects. This study significantly can broaden the diagnostic spectrum of LGMD2B in combination with previous reports about DYSF mutations and may pave the way for a rapidly high-ranked identification of the accurate type of dysferlinopathy.

Pain interference and fatigue in limb-girdle muscular dystrophy R9

Pain is prevalent in individuals with limb-girdle muscular dystrophy (LGMD) R9, but impact on daily living and correlation with fatigue remain unknown. Patient-Reported Outcomes Measurement Information System (PROMIS) pain interference and fatigue short forms were completed annually by 23 children and 54 adults with biallelic fukutin-related protein (FKRP) variants for up to six years. Concurrent motor and pulmonary function were evaluated. Pain interference T-scores were near the normal mean of 50 by linear mixed model analysis (48.5 in children, 51.6 in adults). 58% of participants experienced pain interference levels greater than the general population on at least one assessment. Fatigue T-scores were elevated in adults but not children (49.0 in children, 55.1 in adults), and 75% had at least one elevated fatigue score. Of participants with at least two visits, serial scores were not consistent across visits, without a clear pattern. Pain interference and fatigue were positively correlated (r = 0.55). Both increased with older age (r = 0.21 and 0.41 respectively). Neither differed by sex or ambulation status. Motor (r=-0.32) and pulmonary (r=-0.25) function correlated with fatigue in adults, not children. Results suggest that pain in those with LGMDR9 is variable and episodic, limiting impact on daily life, while fatigue increases over time.

Concept Elicitation Interviews and Conceptual Model to Understand the Patient Experience of Limb Girdle Muscular Dystrophy

INTRODUCTION

Limb girdle muscular dystrophies (LGMDs) are a group of rare and heterogeneous disorders involving progressive wasting of shoulder and pelvic girdle musculature. This study aimed to generate qualitative evidence on patient and caregiver experiences with symptoms and impacts of LGMD on overall function and daily life for sarcoglycanopathy subtypes 2C/R5, 2D/R3, and 2E/R4.

METHODS

Twenty-three individuals with LGMD with (n = 5) or without (n = 18) a caregiver participated in 60-minute semi-structured video interviews. Interview transcripts were analyzed using thematic analysis. Differences in patient experience by ambulation status and LGMD subtype were examined.

RESULTS

Participants were ambulatory (n = 14) and non-ambulatory (n = 9), representing three subtypes: 2C/R5 (n = 4), 2D/R3 (n = 12), and 2E/R4 (n = 7), with mean age of 34.8 years (SD = 16.08). 56.5% identified as female. Conceptual saturation was achieved within 18/23 interviews. Ambulatory participants identified difficulty with complex physical activities, e.g., running (n = 11, 78.6%), physical strength (n = 14, 100%), and difficulty with transfers, e.g., difficulty getting off the floor (n = 10, 71.4%). All non-ambulatory participants discussed problems with activities of daily living (ADLs) and transfers, e.g., getting in/out of bed and upper extremity function, particularly reaching (n = 8, 88.9%) and fine motor skills (n = 6, 66.7%). Fatigue and pain were reported by the majority of participants (n = 16, 69.6% and n = 19, 82.6%, respectively). A conceptual disease model was developed illustrating symptoms and impacts and their relationships to disease stage, capturing the patient experience across LGMD disease trajectory.

CONCLUSIONS

This study contributes to the limited evidence describing the patient experience of living with LGMD. The conceptual model can inform patient-centered assessment in future LGMD clinical trials.

A force-based human machine interface to drive a motorized upper limb exoskeleton. a pilot study

Muscular dystrophy is a strongly invalidating disease that causes the progressive loss of motor skills. The use of assistive devices, especially those in support of the upper limb, can increase the ability to perform daily-life activities and foster a partial recovery of the lost motor functionalities. However, for the use of these devices to be truly effective and accepted by patients, their activation must coincide with the user's intention to move. This work describes a new human-machine interface based on the integration of a six-axis force sensor to drive an upper limb motorized exoskeleton. This novel system can detect the patient's intention to move and produce displacements of the robotic device that are of magnitude and direction consistent with the user's wishes. The integration of the force-sensor interface in the BRIDGE/EMPATIA exoskeletal system was successful, and tests performed on both healthy and dystrophic subjects showed promising results, especially for the execution of planar movements.

Patient reported quality of life in limb girdle muscular dystrophy

This study determined the frequency and impact of symptoms on quality of life in patients diagnosed with limb girdle muscular dystrophy (LGMD). Participants with a diagnosis of LGMD in registries based at the Coalition to Cure Calpain-3, the Jain foundation, and the Global FKRP Registry competed a survey to report the frequency and relative impact of themes and symptoms of LGMD. Frequency, mean impact, and population impact scores were calculated, and responses were categorized by age, symptom duration, gender, employment status, use of assistive devices, and LGMD subtypes. 134 participants completed the survey. The most prevalent themes included an inability to do activities (100%), limitation with mobility (99.3%), and lower extremity weakness (97.0%). Themes with the greatest impact were: limitations with mobility, lower extremity weakness, and an inability to do activities. Symptom duration and the use of assistive devices were associated with the presence of multiple themes. Employment was associated with the impact of several themes with no differences in frequency. The prevalence and impact of these themes vary in the LMGD population. The most prevalent and impactful themes were related to weakness, but additional concerns related to emotional challenges should also be considered in clinical and research settings.

A Roadmap to Patient Engagement: Facioscapulohumeral Muscular Dystrophy and the ReSolve Clinical Trial

We describe our efforts to overcome barriers to patient engagement in facioscapulohumeral muscular dystrophy (FSHD) and offer a roadmap that can be replicated in other rare neurologic disorders. We implemented an engagement plan during Clinical Trial Readiness to Solve Barriers to Drug Development for FSHD (ReSolve), an 18-month, multisite, observational study of individuals with FSHD. Elements of our engagement plan included conducting focus groups during protocol development, patient involvement on the ReSolve external advisory committee, creation of a patient advisory committee, and collaboration with patient advocacy groups. Patient feedback led to adaptations in the study protocol and to changes in recruitment and retention methods. Patient engagement ensures that the patient voice contributes to multiple aspects of trial design and implementation. Our engagement efforts exemplify how collaboration with patients and families can be accomplished in FSHD and the resultant roadmap process may be replicable in other rare neurologic diseases.

A Journey with LGMD: From Protein Abnormalities to Patient Impact

The limb-girdle muscular dystrophies (LGMD) are a collection of genetic diseases united in their phenotypical expression of pelvic and shoulder area weakness and wasting. More than 30 subtypes have been identified, five dominant and 26 recessive. The increase in the characterization of new genotypes in the family of LGMDs further adds to the heterogeneity of the disease. Meanwhile, better understanding of the phenotype led to the reconsideration of the disease definition, which resulted in eight old subtypes to be no longer recognized officially as LGMD and five new diseases to be added to the LGMD family. The unique variabilities of LGMD stem from genetic mutations, which then lead to protein and ultimately muscle dysfunction. Herein, we review the LGMD pathway, starting with the genetic mutations that encode proteins involved in muscle maintenance and repair, and including the genotype–phenotype relationship of the disease, the epidemiology, disease progression, burden of illness, and emerging treatments.

Rehabilitation Challenges in Limb-Girdle Muscular Dystrophies

Limb-girdle muscular dystrophy (LGMD) is a burdensome progressive neuromuscular disease, with a great impact upon quality of life. Unlike other types of neuromuscular dystrophies, which have onset in early childhood and severely limit the life expectancy, LGMD is usually diagnosed at young adulthood age. Since no etiological treatment is currently available, physiotherapy and generally, rehabilitation therapy, are mandatory for preserving the functional capabilities of the muscles for as long as possible. Exercise therapy, electrical stimulation or novel therapies such as exoskeleton devices aim towards alleviating the impact of disability. It is ideal that muscular dystrophy should be assessed in interdisciplinary clinics (physical therapy, neurology, cardiology, pneumology, surgery and orthopedics) for proper long-term care. Keywords: LGMD, muscle strength, rehabilitation, quality of life,

User-centred assistive SystEm for arm Functions in neUromuscuLar subjects (USEFUL): a randomized controlled study

Background

Upper limb assistive devices can compensate for muscular weakness and empower the user in the execution of daily activities. Multiple devices have been recently proposed but there is still a lack in the scientific comparison of their efficacy.

Methods

We conducted a cross-over multi-centric randomized controlled trial to assess the functional improvement at the upper limb level of two arms supports on 36 patients with muscular dystrophy. Participants tested a passive device (i.e., Wrex by Jaeco) and a semi-active solution for gravity compensation (i.e., Armon Ayura). We evaluated devices’ effectiveness with an externally-assessed scale (i.e., Performance of the Upper Limb-PUL-module), a self-perceived scale (i.e., Abilhand questionnaire), and a usability scale (i.e., System Usability Scale). Friedman’s test was used to assess significant functional gain for PUL module and Abilhand questionnaire. Moreover, PUL changes were compared by means of the Friedman’s test.

Results

Most of the patients improved upper limb function with the use of arm supports (median PUL scores increase of 1–3 points). However, the effectiveness of each device was related to the level of residual ability of the end-user. Slightly impaired patients maintained the same independence without and with assistive devices, even if they reported reduced muscular fatigue for both devices. Moderately impaired patients enhanced their arm functionality with both devices, and they obtained higher improvements with the semi-active one (median PUL scores increase of 9 points). Finally, severely impaired subjects benefited only from the semi-active device (median PUL scores increase of 12 points). Inadequate strength was recognized as a barrier to passive devices. The usability, measured by the System Usability Scale, was evaluated by end-users “good” (70/100 points) for the passive, and “excellent” (80/100 points) for the semi-active device.

Conclusions

This study demonstrated that assistive devices can improve the quality of life of people suffering from muscular dystrophy. The use of passive devices, despite being low cost and easy to use, shows limitations in the efficacy of the assistance to daily tasks, limiting the assistance to a predefined horizontal plane. The addition of one active degree of freedom improves efficacy and usability especially for medium to severe patients. Further investigations are needed to increase the evidence on the effect of arm supports on quality of life and diseases’ progression in subjects with degenerative disorders.

Trial registration clinicaltrials.gov, NCT03127241, Registered 25th April 2017. The clinical trial was also registered as a post-market study at the Italian Ministry of Health.

Compound heterozygous DYSF variants causing limb-girdle muscular dystrophy type 2B in a Chinese family

BACKGROUND

The dysferlin gene or the DYSF gene encodes the Ca²⁺ -dependent phospholipid-binding protein dysferlin, which belongs to the ferlin family and is associated with muscle membrane regeneration and repair. Variants in the DYSF gene are responsible for limb-girdle muscular dystrophy type 2B (LGMD2B), also called limb-girdle muscular dystrophy recessive 2 (LGMDR2), a rare subtype of muscular dystrophy involving progressive muscle weakness and atrophy. The present study aimed to identify the variants responsible for the clinical symptoms of a Chinese patient with limb girdle muscular dystrophies (LGMDs) and to explore the genotype-phenotype associations of LGMD2B.

METHODS

A series of clinical examinations, including blood tests, magnetic resonance imaging scans for the lower legs, electromyography and muscle biopsy, was performed on the proband diagnosed with muscular dystrophies. Whole exome sequencing was conducted to detect the causative variants, followed by Sanger sequencing to validate these variants.

RESULTS

We identified two compound heterozygous variants in the DYSF gene, c.1058 T>C, p.(Leu353Pro) in exon 12 and c.1461C>A/p.Cys487* in exon 16 in this proband, which were inherited from the father and mother, respectively. In silico analysis for these variants revealed deleterious results by PolyPhen-2 (Polymorphism Phenotyping v2; http://genetics.bwh.harvard.edu/pph2), SIFT (Sorting Intolerant From Tolerant; https://sift.bii.a-star.edu.sg), PROVEAN (Protein Variation Effect Analyzer; http://provean.jcvi.org/seq_submit.php) and MutationTaster (http://www.mutationtaster.org). In addition, the two compound heterozygous variants in the proband were absent in 100 control individuals who had an identical ethnic origin and were from the same region, suggesting that these variants may be the pathogenic variants responsible for the LGMD2B phenotypes for this proband.

CONCLUSIONS

The present study broadens our understanding of the mutational spectrum of the DYSF gene, which provides a deep insight into the pathogenesis of LGMDs and accelerates the development of a prenatal diagnosis.