Isoelectric focusing and electrophoresis of cerebrospinal fluid proteins in muscular dystrophies and spinal muscular atrophies.

In the very few previous investigations of the CSF-proteins in muscular dystrophies the results have generally been reported as normal. In spinal muscular atrophies a barrier-damage pattern of CSF-proteins has been found in amyotrophic lateral sclerosis (ALS). In the present investigation the CSF-proteins were examined by isoelectric focusing and quantitative paper electrophoresis in 13 patients with muscular dystrophies and in 11 patients with spinal muscular atrophies. On isoelectric focusing, CSF-protein abnormalities were found in 85% of the cases with muscular dystrophies and in all patients with spinal muscular atrophies. Differences in the CSF-protein patterns were observed within the group of muscular dystrophies and between these and the cases of spinal muscular atrophies. In ALS and in myotonic dystrophy, abnormal CSF-protein fractions occurred mainly in the alkaline pH-range, while in limb-girdle dystrophy and the patient with facioscapulohumeral dystrophy, aberrant fractions appeared mainly in the acidic region. CSF-protein abnormalities were found in both the alkaline fractions (HAFs) with pI 9.2-9.6 and a fraction with PI 7.1 were found in half of the patients with myotonic dystrophy. The CSF electrophoresis in myotonic dystrophy showed increased levels of beta1-globulin in all cases examined. Signs of barrier-damage were commonly encountered in ALS in contrast to the muscular dystrophies, except for myotonic dystrophy. The results are discussed in terms of possible diagnostic value and with regard to pathogenetic significance, particularly in relation to the current hypothesis of a neural involvement in muscular disorders.