Reinaldo Issao Takata

A deletion including the brain promoter of the Duchenne muscular dystrophy gene is not associated with mental retardation

A total of 161 unrelated Duchenne (DMD) and Becker muscular dystrophy (BMD) patients were screened for deletions in the brain promoter region of the dystrophin gene. Southern blot analysis using a probe for the brain promoter detected a deletion in this region in only one of the DMD families, in a patient with normal intelligence. This deletion also included the promoter of the muscle-type dystrophin and the exons encoding the actin-binding and part of the spectrin-like domains. Our data suggest that deletions in the brain promoter region are rare in DMD and are compatible with normal intelligence.

Intrafamilial variability in dystrophin abundance correlated with difference in the severity of the phenotype

In Duchenne muscular dystrophy, the progression of the disease is always severe and predictable, while in Becker dystrophy there is a wide variability (intra and inter familial) in the severity of the phenotype. We report here a family in which the proband, who is currently 15 years old, is showing a severe DMD progression, while his affected maternal uncle, aged 29, has a more benign course, compatible with BMD. No DNA deletion was detected in both patients. Dystrophin analysis through immunofluorescence and western blotting showed a negative pattern in the youngest patient and a positive one in the oldest. Apparently, this is the first report on intrafamilial variability in dystrophin abundance correlated with a difference in the severity of the phenotype.

Novel point mutations in the dystrophin gene

Duchenne (DMD) and Becker (BMD) type muscular dystrophies are allelic X‐linked recessive disorders caused by mutations in the gene encoding dystrophin. About 65% of the cases are caused by deletions, while 5–10% are duplications. The remaining 30% of affected individuals may have smaller mutations (point mutations or small deletions/insertions) which cannot be identified by current diagnostic screening strategies. In order to look for pathogenic small mutations in the dystrophin gene, we have screened the 18 exons located in the hot spot region of this gene through two different single strand conformation polymorphism (SSCP) conditions. Five different pathogenic mutations were identified in 6 out of 192 DMD/BMD patients without detectable deletions: 2 nonsense, 1 bp insertion, 1 bp deletion and 1 intronic. Except for the intronic change, which alters a splice site, all the others cause a premature stop codon. In addition, 8 apparently neutral changes were identified. However, interestingly, one of them was not identified in 195 normal chromosomes, although it was previously described in a DMD patient from a different population. The possibility that this mutation may be pathogenic is discussed. Except for two neutral changes, all the others are apparently here described for the first time. Hum Mutat 10:217–222, 1997.

Clinical diagnosis of heterozygous dystrophin gene deletions by fluorescence in situ hybridization

Two-thirds of patients affected by Duchenne or Becker muscular dystrophy (DMD/BMD) carry large intra-genic deletions in the dystrophin gene. In males, the deletions can be efficiently detected using multiplex polymerase chain reaction (PCR) and Southern blotting. In contrast, deletion detection in carrier females is complicated by the presence of a normal gene copy on the second X-chromosome. We have analyzed the boundaries of 570 deletions and 34 duplications in the dystrophin gene identified in the São Paulo and Leiden diagnostic laboratories. The data were used to select an optimal set of cosmid probes for the detection of the most frequently deleted areas of the dystrophin gene. Six cosmids were evaluated in fluorescence in situ hybridization (FISH) experiments to assess deletions in 21 heterozygous deletion-carriers and nine controls. No discrepancy was found between the FISH analysis and the molecular data, demonstrating the accuracy of the technique for carrier detection in Duchenne and Becker muscular dystrophy.

Common recessive limb girdle muscular dystrophies differential diagnosis: why and how?

Limb girdle muscular dystrophies are heterogeneous autosomal hereditary neuromuscular disorders. They produce dystrophic changes on muscle biopsy and they are associated with mutations in several genes involved in muscular structure and function. Detailed clinical, laboratorial, imaging, diagnostic flowchart, photographs, tables, and illustrated diagrams are presented for the differential diagnosis of common autosomal recessive limb girdle muscular dystrophy subtypes diagnosed nowadays at one reference center in Brazil. Preoperative image studies guide muscle biopsy site selection. Muscle involvement image pattern differs depending on the limb girdle muscular dystrophy subtype. Muscle involvement is conspicuous at the posterior thigh in calpainopathy and fukutin-related proteinopathy; anterior thigh in sarcoglycanopathy; whole thigh in dysferlinopathy, and telethoninopathy. The precise differential diagnosis of limb girdle muscular dystrophies is important for genetic counseling, prognostic orientation, cardiac and respiratory management. Besides that, it may probably, in the future, provide specific genetic therapies for each subtype.

Phenotypic Variability of Dystrophinopathy Symptomatic Female Carriers

BACKGROUND Dystrophinopathies are X-linked muscular dystrophies characterized by pathogenic mutations in the dystrophin gene. Symptomatic dystrophinopathy female carriers may present with limb-girdle weakness. The diagnosis may be challenging in the absence of affected male relatives. We aimed to describe the phenotypic variability in a series of molecular-confirmed female dystrophinopathy patients. METHODS This is a retrospective analysis of medical records from 1997 to 2015. RESULTS Ten female dystrophinopathy patients were selected, two with unusual phenotypes: one with early joint contractures muscular dystrophy and the other with very late onset myopathy. Muscle imaging studies demonstrated predominant asymmetric fat replacement. Muscle biopsy immunohistochemistry demonstrated clear mosaic pattern in two cases and only subtle reduction of dystrophin intensity in three. CONCLUSIONS Adequate diagnosis is fundamental for genetic counseling and cardiologic follow-up. Female patients with dystrophinopathy may present unusual phenotypes such as early contractures and very late onset myopathy.

Central core myopathy with autophagy

Autor filiations (specific) Ana Cotta, MD, PhD (8702@sarah.br) Department of Pathology, SARAH Network of Rehabilitation Hospitals, Av. Amazonas, 5953, Belo Horizonte, Brazil, CEP 30510-000 Julia F. Paim, MD, MSc (julia@sarah.br). Department of Pathology, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil Rita de C. Pavanello, MD (rpavanello@ib.usp.br) Human Genome and Stem Cells Research Center, Genetics and Evolutionary Biology, IBUSP, University of São Paulo, São Paulo, Brazil Leticia Nogueira, BSc (leticianfp@yahoo.com.br) Human Genome and Stem Cells Research Center, Genetics and Evolutionary Biology, IBUSP, University of São Paulo, São Paulo, Brazil Leonardo G. Leão, BSc (leo_galleni@hotmail.com) Human Genome and Stem Cells Research Center, Genetics and Evolutionary Biology, IBUSP, University of São Paulo, São Paulo, Brazil Rafael Xavier-Neto, MD (9679@sarah.br) Department of Neurology, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil Monica M. Navarro, MD (400039@sarah.br) Department of Pediatrics and Genetics, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil Elmano Carvalho, MD, PhD (9230@sarah.br) Department of Neurophysiology, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil Jaquelin Valicek, MD (400585@sarah.br) Department of Neurophysiology, SARAH Network of Rehabilitation Hospitals, Belo Horizonte, Brazil Eni B. Silveira, PhD (7341@sarah.br) Department of Electron Microscopy, SARAH Network of Rehabilitation Hospitals, Brasília, Brazil Reinaldo I. Takata, PhD (202911@sarah.br) Department of Molecular Biology, SARAH Network of Rehabilitation Hospitals, Brasília, Brazil Mariz Vainzof, PhD (mvainzof@usp.br) Human Genome and Stem Cells Research Center, Genetics and Evolutionary Biology,