Clinical and genetic profile of Brazilian patients with dysferlinopathies – A retrospective study
Introduction: Dysferlinopathies are a group of conditions that are caused by mutations in the dysferlin gene. Objectives: To characterize the clinical phenotypes and genotypic spectrum of dysferlinopathies patients and to estimate the progression of functional and motor decline. Design and setting: Retrospective analysis of the medical records of patients followed up at our institution between 1995 and 2020. Methods: Patients were selected based on the following inclusion criteria:(i) Identification of a mutation defined as pathogenic in homozygosis or compound heterozygosis in the Dysf gene;or (ii)compatible clinical manifestations and decreased expression of dysferlin in immunohistochemistry on muscle biopsy. Classification of the phenotype was based on the first symptoms. Functionality was defined by the Gardner–Medwin & Walton(GMW) scale modified for dysferlinopathy. Results: 23 patients were included in the study. 16 were classified as limb-girdle muscular dystrophy autosomal recessive 2 (LGMDR2), 4 as Miyoshi muscular dystrophy, 2 as proximo-distal onset and 1 as asymptomatic hyperCKemia. Thighs adduction was the most affected movement in the first evaluation (mean strength=3). Plantar flexion was the movement with the greatest decline in strength(mean=-0.10 points on MRC/year;pT, Arg2042Cys and c.2643+1G>A, p.?(splicing), found 3 times each. There was no statistical difference in muscle strength in the first evaluation, motor and functional decline between the phenotypes. Conclusion: While LGMDR2 was the most common phenotype at onset, with the exception of asymptomatic hyperCKemia, there were not a clear difference in the pattern of progression between them.