IMMUNOHISTOCHEMICAL EVALUATION OF MEROSIN DEFICIENCY IN CONGENITAL MUSCULAR-DYSTROPHIES

Objectives. - To determine the prevalence of merosin deficiency in cas es of unclassified congenital muscular dystrophy and to determine the temporal stability of merosin epitopes in fixed and stored archival ma terial. Materials and Methods. - Using an antibody to human merosin we retrospectively studied 12 cases of undiagnosed muscular dystrophy fr om our files to determine the prevalence of merosin deficiency. Where fresh muscle was not available, unstained stored cryostat sections or destained archival stored sections were incubated with the merosin ant ibody. Results. - Two of the 12 cases of undiagnosed muscular dystroph y were merosin-deficient. No difference in intensity of merosin staini ng was found between freshly cut cryostat sections and unstained store d cryostat sections. There was no difference in the intensity of meros in staining in sections archived for up to 10 years. Conclusions. - We conclude that 16% of unclassified muscular dystrophies in our study a re due to merosin deficiency and that merosin antigenicity remains int act in archival stored muscle tissue, facilitating retrospective evalu ation of patients in whom frozen muscle is not available. To our knowl edge, this latter observation has not been reported previously.