Acta Myologica最新文献

Myotonic Dystrophy type 1 (DM1) is the most common muscular dystrophy in adults, affecting 1:8000 individuals. It is a multi-systemic disorder involving muscle, heart, endocrine and respiratory apparatus and eye. The eye symptoms can include ptosis, external ophthalmoplegia, epiphora, and early onset cataracts. Cataracts occur at a much earlier age (usually between 30 and 40) than the general population, where females are usually affected more than men. We studied gender differences in cataract prevalence and treatment age in 243 DM1 patients (134 M; 109 F), aged 18 to 70 years, who were subsequently screened at routine follow-up. For each patient, information was collected on age, sex, CTG expansion, age of cataract onset, and age at cataract surgery, when available. Seventy-three patients, 30 females and 43 males, had cataracts, at a mean age of onset of 41.14 ± 12.64 in females, and 40.36 ± 10.03 in males. Sixty-nine of them underwent cataract surgery, males at an earlier age than females (42.8 ± 9.8 years versus 47.3 ± 12.6 years) and in 52.5% of cases before the age of 40, compared to 17.2% of females. The difference was statistically significant. The assumption that females in general and those with DM1 in particular develop cataracts more frequently and earlier than males is not confirmed, at least in this study. A possible explanation for these results could be related to non-advanced age, the protective role of estrogen and the lower prevalence of smoking in the study population.

Early-onset myopathy, areflexia, respiratory distress, and dysphagia (EMARDD) is caused by homozygous or compound heterozygous mutation in the MEGF10 gene (OMIM #614399). Phenotypic spectrum of EMARDD is variable, ranging from severe infantile forms in which patients are ventilator-dependent and die in childhood, to milder chronic disorders with a more favorable course (mild variant, mvEMARDD). Here we describe a 22 years old boy, offspring of consanguineous parents, presenting a congenital myopathic phenotype since infancy with elbow contractures and scoliosis. The patient developed a slowly progressive muscle weakness with impaired walking, rhinolalia, dysphagia, and respiratory involvement, which required noninvasive ventilation therapy since the age of 16 years. First muscle biopsy revealed unspecific muscle damage, with fiber size variation, internal nuclei and fibrosis. Myofibrillar alterations were noted at a second muscle biopsy including whorled fibres, cytoplasmic inclusion and minicores. Exome sequencing identified a homozygous mutation in MEGF10 gene, c.2096G > C (p.Cys699Ser), inherited by both parents. This variant, not reported in public databases of mutations, is expected to alter the structure of the protein and is therefore predicted to be probably damaging according to ACMG classification. In conclusion, we found a new likely pathogenic mutation in MEGF10, which is responsible for a progressive form of mvEMARDD with myofibrillar alterations at muscle biopsy. Interestingly, the presence of MEGF10 mutations has not been reported in Italian population. Early diagnosis of MEGF10 myopathy is essential in light of recent results from in vivo testing demonstrating a potential therapeutic effect of SSRIs compounds.

The recent approval of disease-modifying therapies for spinal muscular atrophy (SMA) raised the need of alternative outcome measures to evaluate treatment efficacy. In this study, we investigated the potential of muscle quantitative MRI (qMRI) as a biomarker of disease progression in adult SMA3 patients during nusinersen treatment. Six adult SMA3 patients (age ranging from 19 to 65 years) underwent 2-point Dixon muscle qMRI at beginning of nusinersen treatment (T0) and after 14 months (T14) to evaluate the muscle fat fraction (FF) at thigh and leg levels; patients were clinically assessed at T0 and T14 with the Hammersmith Functional Rating Scale Expanded (HFMSE), the Revised Upper Limb Module (RULM) and the 6-minute walk test (6MWT). At T0, vastus lateralis muscle displayed the highest mean FF (67.5%), while tibialis anterior was the most preserved one (mean FF = 35.2%). At T0, a slightly significant correlation of FF with HFMSE (p = 0.042) and disease duration (p = 0.042) at thigh level and only with HFMSE (p = 0.042) at leg level was found. At T14, no significant change of mean FF values at thigh and leg muscles was found compared to T0. Conversely, a statistically significant (p = 0.042) improvement of HFMSE was reported at T14. We observed no significant change of FF in thigh and leg muscles after 14 months of nusinersen therapy despite a significant clinical improvement of HFMSE. Further studies with longer follow-up and larger cohorts are needed to better investigate the role of qMRI as marker of disease progression in SMA patients.

This study explored views of users with muscular dystrophies and their caregivers on staff-user relationships and the treatments provided by a Rehabilitation Centre during the pandemic. Patients and relatives were asked to anonymously complete an open-ended questionnaire exploring their views on these aspects. Fifty-four patients and 40 caregivers gave their informed consent and participated in the survey. Fifty-three patients were adults, 28% suffering from Duchenne/Becker muscular dystrophy. Patients reported 269 comments on health care services provided during the pandemic, 132 (49%) concerning positive aspects and 137 (51%) negative aspects. The prompt restart of the rehabilitation therapies and the staff closeness over the pandemic were the practical aspects most frequently appreciated (46.9%), while closer family contacts and the perception of being able to rely on the Centre's constant support were the most cited psychological aspects (53.1%). Architectural barriers, difficulties in accessing public health services, economic difficulties, and lack of support from welfare and other agencies were the practical critical points most frequently reported (89%). In addition, social isolation, and loneliness due to fear of contagion were the most negative psychological aspects (10.1%). As regard the caregivers' views, participants reported 151 comments. Of these, 86 (56.9%) were positive and 65 (43.1%) were negative. Among the positive aspects, the psychological ones - such as closer family contacts, not feeling abandoned and counting on the constant Centre's professional support prevailed (53.5%). As for the negative aspects, most caregivers (92.6%) believe that the pandemic exacerbated their financial and bureaucratic difficulties, particularly in poorer families.

Bcl2-associated athanogene 3 (BAG3) is a multifunctional cochaperone responsible for protein quality control within cells. BAG3 interacts with chaperones HSPB8 and Hsp70 to transport misfolded proteins to the Microtubule Organizing Center (MTOC) and degrade them in autophagosomes in a process known as Chaperone Assisted Selective Autophagy (CASA). Mutations in the second conserved IPV motif of BAG3 are known to cause Dilated Cardiomyopathy (DCM) by inhibiting adequate removal of non-native proteins. The proline 209 to leucine (P209L) BAG3 mutant in particular causes the aggregation of BAG3 and misfolded proteins as well as the sequestration of essential chaperones. The exact mechanisms of protein aggregation in DCM are unknown. However, the similar presence of insoluble protein aggregates in Charcot-Marie-Tooth disease type 2 (CMT2) induced by the proline 182 to leucine (P182L) HSPB1 mutant points to a possible avenue for future research: IPV motif. In this review, we summarize the molecular mechanisms of CASA and the currently known pathological effects of mutated BAG3 in DCM. Additionally, we will provide insight on the importance of the IPV motif in protein aggregation by analyzing a potential association between DCM and CMT2.

[This retracts the article DOI: 10.36185/2532-1900-058.].

Mutations in the genes encoding collagen VI cause Bethlem myopathy (MIM 158810), Ullrich congenital muscular dystrophy (MIM 254090), and myosclerosis myopathy (MIM #255600). BM is a dominantly inherited disorder, characterised by proximal muscle weakness and joint contractures mainly involving the elbows, ankles, and fingers, which usually follows a relatively mild course. By contrast, UCMD is a severe muscular dystrophy characterized by early onset, rapidly progressive muscle wasting and weakness, proximal joint contractures and distal joint hyperlaxity. Rapid progression usually leads to early death due to respiratory failure. UCMD is usually inherited as an autosomal recessive trait though dominant de novo heterozygous variants have recently been reported. We describe a further patient with UCMD classical presentation who showed, at the NGS analysis, the de novo variant c.6210+1G > A in the intron 16 of the gene COL6A3, known in the literature as pathogenic (VCV0000949S6.5).

Spinal muscular atrophy is a progressive and severe hereditary (autosomal recessive) neuromuscular disease characterized by lower motor neuron degeneration in the spinal cord and brainstem causing a clinical picture of progressive muscle atrophy and weakness of skeletal and respiratory muscles. There is an ongoing discussion on the extent to which other tissues might be affected in patients with SMA. Several animal models and some case reports or small case series report involvement of other organ systems, such as peripheral nerve, brain, muscle, heart, vascular system, and pancreas. Recent literature reviews identified a number of cases with vascular abnormalities. We present two consecutive cases of patients diagnosed with SMA who developed peripheral circulation disturbances and combine the findings with a thorough review the literature.