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Browsing by Author "Santos, M"

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  • Ryanodine myopathies without central cores-clinical, histopathologic, and genetic description of three cases.
    Publication . Rocha, J; Taipa, R; Melo Pires, M; Oliveira, J; Santos, R; Santos, M
    BACKGROUND: Mutations in ryanodine receptor 1 gene (RYR1) are frequent causes of myopathies. They classically present with central core disease; however, clinical variability and histopathologic overlap are being increasingly recognized. PATIENTS: Patient 1 is a 15-year-old girl with mild proximal, four-limb weakness from age 5, presenting with a progressive scoliosis starting at age 10. Patient 2 is an 18-year-old girl with progressively worsening muscle hypotrophy and mild proximal, four-limb weakness. She developed a rapidly progressive scoliosis from age 11 and needed surgical treatment at age 14 years. Patient 3 is an 11-year-old boy with moderate proximal limb weakness and progressive neck flexor weakness, first noticed at age 2. Muscle biopsies revealed type 1 fiber predominance (Patients 1 and 2) or abnormal type 1 fiber uniformity (Patient 3). Different RYR1 variants were identified in all patients. In Patients 1 and 3, these changes were validated as being pathogenic. CONCLUSIONS: These patients illustrate early-onset, progressive myopathies with predominant axial involvement. Histopathologic findings were abnormal but not specific for a diagnosis, particularly central core myopathy. Genetic testing helped broaden the range of phenotypes included in the RYR1-related myopathies. Our patients reinforce the need to recognize the broad histopathologic variability of RYR1-related myopathies and sometimes lack of pathognomonic findings that may reduce the diagnostic threshold of this disease. We suggest that the predominance of type 1 fibers and involvement of axial muscles may be an important element to consider the RYR1 gene as candidate.
    2014Journal article Open access Show more
  • A whole genome screen for association with multiple sclerosis in Portuguese patients
    Publication . Santos, M; Pinto-Basto, J; Rio, ME; Sá, MJ; Valença, A; Sá, A; Dinis, J; Figueiredo, J; Bigotte de Almeida, L; Coelho, I; Sawcer, S; Setakis, E; Compston, A; Sequeiros, J; Maciel, P
    Multiple sclerosis (MS) is common in Europe affecting up to 1:500 people. In an effort to identify genes influencing susceptibility to the disease, we have performed a population-based whole genome screen for association. In this study, 6000 microsatellite markers were typed in separately pooled DNA samples from MS patients (n=188) and matched controls (n=188). Interpretable data was obtained from 4661 of these markers. Refining analysis of the most promising markers identified 10 showing potential evidence for association.
    2003Journal article Open access Show more