- CPK:
- normal CPK is approximately 200 units;
- in DMD, CPK can be elevated 10-20 fold, but may be as high as 10,000 IU/L;
- serum CPK may also be elevated in
limb girdle dystrophy,
dermatomyositis, type IV
spinal muscular atrophy, but will not be elevated as high as DMD;
- marked elevation of SGOT may be elevated in polymyositis;
- Dystrophin:
- absence or deficiency of dystrophin on surface membrane of muscle cells is a key
marker for this disease and has facilitated determination of female carriers;
- one may also identify female characters by measuring
CPK levels;
- assessment of dystrophin levels on muscle biopsy also provides an
index of prognosis for severity of the muscular dystrophy
- Biopsy:
- muscle biopsy is the most effective test to distinguish the various muscular dystrophies;
- general histological features include:
- variation in fiber size;
- central location of muscle fibers;
- degeneration of regional muscle fibers;
