3rd Workshop of the MYOCLUSTER project: EUROMEN

The third Workshop of the MYO-CLUSTER project EUROMEN was held in Naarden on 13 and the 14 September 2002. 23 Participants attended it from France, Germany, Italy, The Netherlands, Poland and UK. The aims of this Workshop were to present new insights in laminopathies and emerinopathies, to give recommendations for cardiac management of these disorders and to expose the current status of the mutation databases related to the two genes responsible of these disorders: the lamin A/C gene and the emerin gene.

Whereas mutations in the emerin gene (EMD) give rise to one phenotype, the X-linked form of Emery-Dreifuss muscular dystrophy (XL-EDMD), up to six phenotypes are associated with mutations in the lamin A/C gene (LMNA): the autosomal dominant and recessive forms of Emery-Dreifuss muscular dystrophy (AD- & AR-EDMD), the dilated cardiomyopathy with conduction-system defect (DCM-CD), the autosomal dominant limb-girdle muscular dystrophy type 1B (LGMD1B), the Dunnigan-type familial partial lipodystrophy (FPLD), an autosomal recessive form of axonal Charcot-Marie-Tooth disease (AR-CMT2) and the mandibulo-acral dysplasia (MAD). The clinical spectrum of these disorders was discussed with a special emphasis on the tissue-specificity of the various laminopathies (i.e striated muscles in EDMD, LGMD1B and DCM-CD / adipose tissue in FPLD / bone tissue and adipose tissue in MAD / peripheral nerve in AR-CMT2) and their possible overlaps.
As cardiac disease invariably developed in emerinopathies and in laminopathies affecting the striated muscles, the spectrum and natural history of cardiac involvement was discussed in details. Sudden deaths appear to be more frequent in laminopathies than in emerinopathies. Therefore implantation of an implantable cardiac defibrillator as well as a close cardiac follow-up is essential and highly recommended for patient with laminopathy.
The spectrum of mutations in LMNA and EMD genes was presented through two mutation databases currently under development, which will at term collect all clinical and genetic data of each individual carrying either EMD or LMNA mutations. A consensus was reached regarding the definition of the clinical form that will be used for these databases to collect detailed and relevant clinical symptoms. It was noticed also that additional genes might be responsible for Emery-Dreifuss muscular dystrophy as no mutation was found in some patients with typical EDMD phenotypes. Both positional cloning and candidate gene screening are currently in progress to identify such genes. Several studies on the cellular consequences of mutations in EMD and LMNA genes were presented; interactions of lamin A/C and emerin with different nuclear components were discussed.

An extended report of this meeting is published in Neuromuscular Disorders, Volume 13, No. 6, August 2003.

Dr. Gisèle Bonne (Paris, France)

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