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Limb-Girdle Muscular Dystrophies-LGMD

Limb-Girdle Muscular Dystrophies-LGMD

They include dystrophies that show symptoms in childhood or adulthood and are not associated with X chromosome mutations, such as in Duchenne or Becker Muscular Dystrophy. They are distinguished in many categories according to the location of the mutation and the protein that is damaged and can be inherited autosomally either in a recessive or dominant way. They are generally present at 1: 14,500 to 123,000 births worldwide, but sarcoglycanopathies in 1: 178,000 births.

 

Clinical manifestations mainly involve muscle weakness, either in the muscles near torso or in distant muscles secondarily, as well as in the muscles of the abdomen or neck rarely. Moreover, in the most rare cases, orthopedic complications such as scoliosis, respiratory and cardiac problems such as cardiomyopathy are present. Muscles may be either hypertrophic or atrophic, depending on the type of mutation. Finally, incidents with rigid spine and speech problems have been recorded.

 

Limb-Girdle autosomal recessive muscular dystrophies

Here are the four subgroups of sarcoglycanopathies (α or LGMD2D, β or LGMD2E, γ or LGMD2C and δ or LGMD2F), calpainopathy (LGMD2A), dysferlinopathy (LGMD2B) and other very rare dystroglycanopathies. In particular dysferlinopathy is distinguished in three additional subcategories: Miyoshi myopathy, DMAT and rigid spine dysferlinopathy.

In the first category, the mutations are related to sarcoglycans, which normally support the cytoskeleton of muscle cells and the binding of dystrophies to the sarcoglycans, while calpain and dysferline are proteins that normally help in the repair and reconstruction of muscle cells when necessary.

 

Autosomal dominant  Limb-Girdle muscular dystrophies

They are very rare and are characterized by LGMD1A and LGMD1H initials. They mainly concern adults, without excluding the case of onset of symptoms during childhood. Generally the symptoms are related to gradually generalized muscle weakness, respiratory and cardiac problems, speech problems, but again they depend on the type of mutation.

 

Management

There is no cure and symptom management should be proportional to each type of LGMD. General guidelines that can increase life expectancy and improve quality of life are:

  • Check body weight and avoid obesity.
  • Physiotherapy and stretching exercises to promote movement and avoid muscle contractions.
  • Use auxiliaries e.g. wheelchairs, orthotics for ease of movement.
  • Surgical interventions for the correction of orthopedic complications e.g. scoliosis.
  • Use of respirators in case of respiratory problems and regular monitoring by a pneumologist.
  • Cardiac monitoring especially in cases of cardiomyopathy.
  • Social and emotional support for social inclusion.

For more details on respiratory and cardiac monitoring, physiotherapy, genetic counseling and medication, visit the Standards of Care.

 

Information about clinical trials conducted globally: https://www.centerwatch.com/clinical-trials/listings/condition/350/muscu... and https://clinicaltrials.gov/ct2/home.

 

References

  • Elena Pegoraro, Limb-Girdle Muscular Dystrophy Overview, U.S. National Library of Medicine, GeneReviews, 2012, https://www.ncbi.nlm.nih.gov/books/NBK140
  • NORD (National Organization for Rare Disorders), Rare diseases, https://rarediseases.org/rare-diseases/
  • Muscular Dystrophy Association, About Neuromuscular Diseases, June 08, 2017, https://www.mda.org/disease/
  • Straub, V., Bushby, K., The childhood Limb-Girdle muscular dystrophies, Semin. Periatr., Neurol., 2006, 13, pp. 104-114.
  • Rosales, X.Q., Tsao, C.Y., Childhood onset of Limb-Girdle muscular dystrophy, Pediatr. Neurol., 2012, 46, pp. 13-23.
  • Broglio, L., Tentorio, M., Cotelli, M.S., et al, Limb-Girdle muscular dystrophy-associated protein diseases, The Neurologist, 2010, 16(6), pp. 340-342.
  • Kramerora, I., Beckmann, J.S., Spencer, M.J., Molecular and cellular basis of calpainopathy (Limb-Girdle muscular dystrophy type 2A), Biochim. Biophys. Acta, 2007, 1772, pp. 128-144.
  • Daniele, N., Richard, I., Bartoli, M., Ins and outs of therapy in Limb-Girdle muscular dystrophies, Int. J. Biochem. Cell B., 2007, 39, pp. 1608-1624.
  • Bushby, K., Diagnosis and management of the Limb-Girdle muscular dystrophies, Pract. Neurol., 2009, 9, pp. 314-323.

Muscular Dystrophy Association