Limb–Girdle Muscular Dystrophy
Diagnostic Criteria
The limb–girdle muscular dystrophies (LGMD) are a group of genetically determined progressive disorders of muscle in which the pelvic or shoulder girdle musculature is predominantly or primarily involved. The term was suggested to recognize the existence of cases which could not be definitively diagnosed as either X–linked muscular dystrophy or facioscapulohumeral muscular dystrophy in the classifications of Stevenson in 1953 and Walton & Nattrass in 1954.

Since then the existence of the group as a separate entity has been questioned because of the overlap of symptomatology with patients who can now be proved to have disorders which are known to be clinically and genetically different. For example, patients with Becker muscular dystrophy and manifesting carriers of dystrophin mutations were frequently diagnosed as having ‘Limb–girdle muscular dystrophy’ before the availability of direct genetic and dystrophin analysis for these conditions.

Disorders such as spinal muscular atrophy and mitochondrial and metabolic myopathies have also been the subject of diagnostic confusion as all of these conditions may present with weakness in a limb–girdle distribution. Nonetheless, some patients remain in whom the diagnosis of LGMD remains appropriate and this is still a heterogeneous group. The category of limb–girdle muscular dystrophy includes a number of separate and genetically distinct conditions, the molecular basis of some of which is now being resolved. Based on the collection of over 90 families and sporadic cases of LGMD presented in advance of an ENMC sponsored workshop on the limb–girdle muscular dystrophies.

The following criteria are for inclusion and exclusion of the diagnosis are suggested. These criteria encompass the range of symptoms and findings in the different groups diagnosed as LGMD and are suggested as a review of the current situation with regard to diagnosis in these conditions. As the molecular basis for each of these phenotypic varieties of LGMD becomes defined, it will become appropriate to provide diagnostic criteria for each separately.

(Inclusion criteria are indicated with an ‘I’, ‘E’ denotes exclusion criteria and ‘C’ stands for comment.)

Address:
Limb–Girdle Muscular Dystrophy
K. M. D. Bushby,
Dept. of Human Genetics,
University of Newcastle upon Tyne, United Kingdom.