Normal distribution of collagen IV in renal basement membranes in Epstein's syndrome

Abstract

Background - Epstein's syndrome is defined as a subtype of Alport's syndrome, and is distinguished from the other subtypes by accompanying macrothrombocytopenia. Mutations in collagen IV genes are known to be involved in the pathogenesis of typical Alport's syndrome. However, the presence of an underlying genetic defect has not been demonstrated in Epstein's syndrome. Aim - To clarify the involvement of collagen IV in Epstein's syndrome. Methods - The distribution of the α(IV) chain was studied in renal specimens obtained from three patients with Epstein's syndrome using chain specific monoclonal antibodies and an antigen retrieval procedure. Results - The patients showed a normal distribution of α(IV) chains: α1(IV) and α2(IV) were expressed ubiquitously, whereas expression of α3(IV) through to α6(IV) chains was limited to the glomerular basement membrane, Bowman's capsular basement membrane, and/or a portion of the tubular basement membrane. Conclusions - These results suggest that genes other than those encoding α(IV) chains are responsible for the pathogenesis of Epstein's syndrome.