The usefulness of myoglobin radioimmunoassays to diagnose and monitor hereditary forms of muscular dystrophy linked to the X-chromosome and to identify its carriers

A total of 376 children suffering from malignant muscular dystrophy (DMD), which is transmitted by recessive genes, were subjected to 478 radioimmunological tests for the presence of myoglobin (Mb) in the serum and found to be positive in 98% of the cases. There was a correlation between the Mb values and certain enzymes produced in the muscles, in particular CK and LDH, whereas no such link could be established regarding the age of the patients. The increases in the Mb values and related parameters seen in benign forms of muscular dystrophy failed to attain statistical significance, nor did the Mb values determined within the individual age groups permit any statistically relevant conclusions to be drawn as to the therapeutic success. Out of 58 proven carriers 73% were positive on the Mb tests, as compared to no more than 10% of the suspected carriers (the CK values remaining within normal limits). Among suspected juvenile carriers (sisters of DMD patients), increased Mb values were more frequent (25%) than increased CK values (12%). Within the group of suspected carriers there was a significant correlation between the increases in Mb and CK, which was absent in the proven carriers. One asset of radioimmunological tests to detect Mb in the serum is their superior sensitivity. They may yield valuable information in addition to that provided by muscle enzyme measurements, in particular in specific situations like those occurring during follow-up observations, in the assessment of drugs acting on muscular permeability and in the identification of carriers of either type of disease. (TRV)