Analysis of Protein Expression in Muscular Dystrophies

The preceding chapters have dealt with the detection of gene mutations and the following chapters deal with protein analysis. This chapter links the two by describing the effect that different types of mutations have on protein synthesis, and how this may be used in the investigation of muscular dystrophy (MD). Analysis at the DNA level can be performed with a simple blood sample, but analysis at the protein level requires a sample of the tissue expressing the target protein. Although proteins such as emerin may be detected in a skin biopsy, most of the diagnostic proteins are only expressed in muscle. The taking of a skeletal muscle biopsy for histological analysis has been part of the routine for a diagnostic work-up for many years, and the practice of storing such samples in an archive was of great importance when diagnostic protein analysis first started in the MDs, with the identification of the Duchenne/Becker gene product, dystrophin. Now that there is an increasing range of gene products to analyze, the taking of a muscle biopsy is an invaluable asset to the diagnostic protocol (1 ), and analysis of protein expression is established as an essential link between the underlying genotype and the manifestations of clinical severity.