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Muscular Dystrophy

Description
Muscular dystrophy is a term used to describe a number of inherited disorders characterized by progressive weakness and wasting of the muscles. The most common and severe type is Duchenne's muscular dystrophy (MD), in which a genetic defect leads to the formation of an abnormal type of muscle protein called dystrophin. The types of MD are classified according to the location of the muscles involved, the age that symptoms appear, the rate that symptoms progress, and the manner in which the defective gene is passed on. For example, the genes for Duchenne's and Becker's MD are X-linked recessives - that is, they generally affect only boys but are carried and passed on by women. Principle symptoms include: progressive muscle wasting, weakness, and loss of function; in Duchenne's MD, delayed development of basic muscle skills and coordination in children - common signs include poor balance with frequent falls, walking difficulty with waddling gait and calf pain, and limited range of movement; obesity; joint contracture; cataracts, frontal baldness, drooping eyelids, gonadal atrophy, and mental impairment. There is no specific treatment or cure to halt MD. Physical therapy, exercise, orthopedic appliances (such as braces and wheelchairs), or corrective orthopedic surgery may help preserve muscle function and prevent joint contractures as much as possible and improve quality of life. In 1993, researchers announced in a landmark discovery that gene therapy can help prevent muscle destruction and preserve muscle function in Duchenne and Becker muscular dystrophies.

Who is at Risk?
Muscular dystrophy is a genetically determined disease, although why the individuals who are genetically the same get MDs of different severity is not known.

Source: Health Scout Network

Study Links Dozens of Proteins to Rare Degenerative Muscle and Nerve Diseases
A team of TSRI scientists has identified more than 50 previously unknown proteins and has associated several of them with rare human degenerative muscle and nerve diseases - a huge step forward. Led by TSRI Professors Larry Gerace, Ph.D. and John R. Yates III, Ph.D., the team used a technique called subtractive proteomics to identify 62 new proteins in the inner nucleus membrane of the human cell. When certain inner membrane proteins are mutated, they cause disease.

The team demonstrated that 23 of these proteins are linked with strong probability to 14 rare muscle-wasting diseases such as congenital muscular dystrophy, Limb-Girdle muscular dystrophy, and spinal muscular dystrophy, and several forms of neurodegenerative Charcot-Marie-Tooth disease. Knowing the proteins that may cause or contribute to these diseases is a first step in the long process of looking for ways to detect, prevent, or treat them. The study has the potential to clarify a significant number of the more than 300 human dystrophies for which a causative gene has not been identified.

The new nuclear membrane proteins identified in this study map to chromosomal regions where the following dystrophies have been localized:

  • Congenital Ptosis, hereditary type 1
  • Charcot-Marie-Tooth Disease 2A
  • Congenital Muscular Dystrophy 1B
  • Limb-Girdle Muscular Dystrophy 2B
  • Charcot-Marie-Tooth Disease 2A
  • Facioscapulohumeral Muscular Dystrophy (FSH)
  • Spinal Muscular Atrophy, Types 1, 2, and 3
  • Limb-Girdle Muscular Dystrophy 1A/1B
  • Arthogryposis: neurogenic, mild
  • Blepharophimosis 2
  • Charcot-Marie-Tooth Disease 2A
  • Distal Arthrogryposis, type 2B
  • Congenital Fibrosis of Extraocular Muscles 1
  • Distal Myopathy

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