NORMAL-DISTRIBUTION OF COLLAGEN-IV IN RENAL BASEMENT-MEMBRANES IN EPSTEINS-SYNDROME

Background-Epstein's syndrome is defined as a subtype of Alport's synd rome, and is distinguished from the other subtypes by accompanying mac rothrombocytopenia. Mutations in collagen IV genes are known to be inv olved in the pathogenesis of typical Alport's syndrome. However, the p resence of an underlying genetic defect has not been demonstrated in E pstein's syndrome. Aim-To clarify the involvement of collagen IV in Ep stein's syndrome. Methods-The distribution of the a(IV) chain was stud ied in renal specimens obtained from three patients with Epstein's syn drome using chain specific monoclonal antibodies and an antigen retrie val procedure. Results-The patients showed a normal distribution of al pha(IV) chains: alpha 1(IV) and alpha 2(IV) were expressed ubiquitousl y, whereas expression of alpha 3(IV) through to alpha 6(IV) chains was limited to the glomerular basement membrane, Bowman's capsular baseme nt membrane, and/or a portion of the tubular basement membrane. Conclu sions-These results suggest that genes other than those encoding alpha (IV) chains are responsible for the pathogenesis of Epstein's syndrome .