[Diagnostic techniques described in the study of Duchenne/Becker muscular dystrophy]. / Técnicas diagnósticas descritas en el estudio de la distrofia muscular de Duchenne/Becker.

INTRODUCTION: Duchenne/Becker muscular dystrophy (DMD/B) is one of the commonest myopathies, with an incidence of 1/3,500 male live births. It is characterized by the slow degeneration of muscle fibres, so that the patient has become an invalid by the age of 10 years, followed by death from respiratory or cardiac failure. It has a sex linked recessive mode of inheritance. DEVELOPMENT: The gene causing this disorder is the DMD gene and is found on the short arm of the X chromosome. The commonest mutations of this gene are deletions. Many molecular techniques for study of the disorder have been developed over the years. These include the Southern Blot, polymerase chain reaction (PCR), use of the Short Tandem Repeat (STR), polymorphic length restriction fragments (RFLP), Western Blot for the study of the protein and others. CONCLUSIONS: In this paper we review the diagnostic tests most widely used in this disease. These have permitted improved study of the various families affected and thus improved the quality of life of the families at risk.

Técnicas diagnósticas descritas en el estudio de la distrofia muscular de Duchenne/Becker / Diagnostic techniques described in the study of Duchenne/Becker muscular dystrophy

Introducción. La distrofia muscular de Duchenne/Becker (DMD/ B) es una de las miopatías mas frecuentes, con un intervalo de incidencia de 1/3.500 varones nacidos vivos. Se caracteriza por una degeneración lenta de las fibras musculares, que provoca la invalidez en la primera década de vida de estos pacientes y luego la muerte por fallos respiratorios o cardíacos. Presenta un patrón de herencia recesivo ligado al sexo. Desarrollo. El gen responsable de esta enfermedad se conoce como gen DMD y se localiza en el brazo corto del cromosoma X. Las mutaciones más frecuentes encontradas en este gen son las deleciones. Existen numerosas técnicas moleculares para el estudio de esta enfermedad, que se han desarrollado durante años, entre las que podemos destacar el Southern Blot, la reacción en cadena de la polimerasa (PCR), utilización de short tandem repeat (STR), los fragmentos de restricción de longitud polimórficos (RFLP) y el Western Blot para el estudio de la proteína. Conclusiones. En este trabajo analizamos los estudios diagnósticos más utilizados en esta enfermedad, que han permitido realizar un mejor estudio de las diversas familias afectadas y mejorar así la calidad de vida de las familias con riesgo (AU)

Diagnóstico prenatal y de portadores en familia con distrofia muscular de Duchenne. Introducción de nuevos marcadores / diagnosis, prenatal and of carriers, in families with Duchenne muscular dystrophy

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[Werdnig-Hoffmann disease. The first prenatal diagnosis in Cuba]. / Enfermedad de Werdnig-Hoffmann. Primer diagnóstico prenatal en Cuba.

INTRODUCTION: Spinal muscular atrophy (SMA) is an autosomal recessive disorder characterized by the degeneration of cells of the spinal cord. The gene was localized on chromosome 5q13 and exists in two almost identical forms, which are distinguished by the change of base on exones 7 and 8. Mutations of the gene of survival motoreneuron (SMN) are the cause of illness. CLINICAL CASE: We report, for the first time in Cuba, the prenatal diagnosis of a type II SMA carrier, using molecular methods for direct detection of the mutation on exones 7 and 8 of the SMN gene, and haplo-identification with microsatellite markers of chromosome 5q as an indirect method. A sample of amniotic liquid was taken at 18 weeks of gestation and the DNA extracted. No deletions were detected on exones 7 and 8 of the foetal DNA, which was therefore normal. CONCLUSIONS: Detection of deletions on the SMN gene is a method which permits detection of the condition (healthy or unhealthy) of the foetus, quickly and reliably, without requiring investigation of the entire family to obtain a result. The method does not require radio-active PCR, the results are clear and precise and may be obtained within 24 hours. It may also take the place of invasive methods such as muscle biopsy and electro-myography and contribute to genetic assessment in families in which there is no DNA of the affected child.