Congenital Muscular Dystrophy (CMD)

Location: Naarden, The Netherlands

(7th Workshop of the International consortium on CMD/2nd Workshop of the MYO CLUSTER project GENRE)

The ENMC Consortium on Congenital muscular dystrophy (CMD) held its seventh meeting in Naarden during the weekend of the 26th-28th October 2001. It was attended by 24 participants from 6 countries, including Denmark, France, Germany, Italy, Turkey and United Kingdom. This workshop was sponsored by the European Community as part of the Myocluster project GENRE.

Congenital muscular dystrophies (CMD) are a heterogeneous group of disabling neuromuscular disorders inherited as autosomal recessive conditions; their overall frequency is approximately 1:10,000. Affected children present with muscle weakness and hypotonia at birth, or within the first six months of life. Motor development is delayed and contractures are common. The progression of the disease is variable and a proportion of children never achieve the ability to walk independently. Mental retardation is a feature of several forms of CMD.

The present meeting focused on the recent clinical, genetic and biochemical advances on the subtypes of CMD characterized by:
i) rigidity of the spine (rigid spine syndrome); ii) CMD with distal laxity;iii) CMD due to deficiency in proteins with enzymatic activity (glycosyltransferases).

CMD and Rigid Spine Syndrome. The gene for one form of CMD with severe rigidity of the spine has recently been identified . This form is now known as RSMD1 (for Rigid Spine Muscular Dystrophy 1) and the defective gene is a novel selenoprotein for which a function has yet to be assigned.
CMD with distal laxity. Recessive mutations in the genes for collagen VI subunits have recently been shown to be responsible for another form of CMD. ( "Ullrich" CMD variant with distal laxity, UCMD). As only some, not all , cases show abnormal expression of collagen VI in muscle , the possibility of heterogeneity was discussed.

CMD due to deficiency in glycosyltransferases. Mutations in genes with possible glycosyltransferase enzymatic activity have recently been identified into 2 other forms of CMD (Muscle Eye Brain disease, with associated mental retardation; and MDC1C, a novel form characterized by muscle hypertrophy and no central nervous system involvement). In addition, a defect in a similar enzyme has recently been reported in an animal model for muscular dystrophy, the myd mouse, providing further evidence for the relevance of these enzymes in CMD.

Refined diagnostic criteria for these forms of CMD were discussed, together with the strategy aimed at arriving a diagnosis in each of these conditions. Management strategies for these disorders and therapeutic approaches to animal models were also discussed, and collaborative studies agreed.

An extended report of this meeting is published in Neuromuscular Disorders, Volume 12, No.9, November 2002.

Prof. Francesco Muntoni, London, UK
Dr. Pascale Guicheney, Paris, France
Chairpersons, CMD consortium

Visit the website of the Myocluster Project GENRE at:

http://www.myocluster.org