Duchenne and Becker muscular dystrophy: a molecular and immunohistochemical approach

Abstract

-Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are caused by mutations in the dystrophin gene. We studied 106 patients with a diagnosis of probable DMD/BMD by analyzing 20 exons of the dystrophin gene in their blood and, in some of the cases, by immunohistochemical assays for dystrophin in muscle biopsies. In 71.7% of the patients, deletions were found in at least one of the exons; 68% of these deletions were in the hot-spot 3' region. Deletions were found in 81.5% of the DMD cases and in all the BMD cases. The cases without deletions, which included the only woman in the study with DMD, had dystrophin deficiency. The symptomatic female carriers had no deletions but had abnormal dystrophin distribution in the sarcolemma (discontinuous immunostains). The following diagnoses were made for the remaining cases without deletions with the aid of a muscle biopsy: spinal muscular atrophy, congenital myopathy; sarcoglycan deficiency and unclassified limb-girdle muscular dystrophy. Dystrophin analysis by immunohistochemistry continues to be the most specific method for diagnosis of DMD/BMD and should be used when no exon deletions are found in the dystrophin gene in the blood.KEY WORDS: Duchenne muscular dystrophy, Becker muscular dystrophy, immunohistochemistry, PCR, deletions, exons. Distrofia muscular de Duchenne e Becker: abordagem molecular e imuno-histoquímicaRESUMO -As distrofias musculares de Duchenne (DMD) e de Becker (DMB) são doenças causadas por mutação no gene da distrofina. Foram estudados 106 casos com a suspeita diagnóstica de DMD/BMD com a analise de 20 exons do gene da distrofina no sangue e biópsia muscular com imuno-histoquímica para distrofina em alguns casos. Em 71,7% dos casos foi encontrada deleção em pelo menos um dos exons, sendo que 68% das deleções localizam-se na região 3´ hot spot. Foram encontradas deleções em 81,5% dos DMD e em todos os BMD, sendo que os sem deleção tinham deficiência de distrofina, incluindo a mulher com DMD. As portadoras sintomáticas não tinham deleções mas anormalidades na distribuição da distrofina no sarcolema. Os outros casos sem deleção, com auxilio da biópsia muscular tiveram outros diagnósticos (atrofia muscular espinhal, miopatia congênita, deficiência de sarcoglicanos, distrofia de cinturasmembros sem classificação). A análise imuno-histoquímica para distrofina na biópsia muscular continua sendo o método mais específico para diagnóstico de DMD/DMB e deve ser utilizado quando não são encontradas deleções do gene da distrophina no sangue.

Exon‐skipped dystrophins for treatment of Duchenne muscular dystrophy: Mass spectrometry mapping of most exons and cooperative domain designs based on single molecule mechanics

“…Δ44–54, Fig.1B) can be problematic in application due in part to inefficient skipping (Aartsma-Rus 2006, 2007), but one such AON cocktail has been theorized to rescue up to 63% of DMD patients by transforming the DMD phenotype into an asymptomatic or mild BMD phenotype (Béroud 2007). Human clinical trials with a single AON designed to skip exon 51 (van Deutekom 2007) lead to modest levels of dystrophin expression (<35% of normal controls) using standard antibody approaches that remain state of the art in expression analysis (Freund 2007), but the limited availability of antibodies can be constraining if one needs to assess expression from every exon. Multi-exon deletion studies would clearly benefit from such assessments, and initial efforts at proteomic profiling of dystrophin in muscle suggest detectability (Lewis 2009).…”

Duchenne or Becker muscular dystrophy: A clinical, genetic and immunohistochemical study in China

“…Thus, immunohistochemistry of muscle biopsies remains the gold standard for the diagnosis of DMD/BMD, but it is a more invasive procedure. [31] It should therefore be used in cases when the patient symptoms, family history and clinical findings suggest DMD or BMD, but molecular analysis fails to find any mutations that are specific to the DMD gene.…”

Dystrophin Degradation in Skeletal Muscles with Lipid Enrichment in Cattle

“…Among muscular dystrophies, Duchenne type is most common as it accounts for approximately 50 percent of all clinical cases [2,4,12,20,27]. Progressive weakness and muscle wasting caused by degenerating muscle fibers begins in the upper legs and pelvis before spreading into the upper arms.…”

“…Patients may experience breathing problem and respiratory infections. Bone thinning and scoliosis are also commonly observed symptoms [2,4,12,20,27].…”