Importance of monitoring calcium & calcium related properties in carrier detection for Duchenne muscular dystrophy.

ABSTRACT

Calcium and calcium dependent enzymes viz., calcium ATPase, protein kinase C and calcium activated neutral protease (milli CANP mCANP) were studied in the erythrocytes, platelets and lymphocytes of obligate carriers, in order to assess the usefulness of these indices for detection of carriers for Duchenne muscular dystrophy (DMD). With the exception of mCANP and lymphocyte calcium ATPase, other calcium dependent enzyme activities showed considerable overlap between carriers and control. Since the increase in the level of platelet mCANP was found in all affected boys (no false negatives) and obligate carriers, and patients with other myopathic conditions and some neurogenic causes did not show high platelet mCANP activity, this parameter could be considered as a good phenotypic index. Unlike SCK, the platelet mCANP of carriers did not overlap that of controls, hence tests are to be carried out to verify its usefulness as an index of carrier state in mutations other than DNA deletion since testing of non-deletion is both costly and has practical limitations.