To the Editor: In the January 24 issue of the Journal, Julian et al. presented a superb paper on familial IgA nephropathy.1 However, we would like to take issue with their statement, “The clustering of IgA nephropathy exhibited in our study was not simply a chance finding secondary to an exaggerated degree of inbreeding.” This lack of inbreeding is used to support their argument that a hereditary mechanism is involved. They seem to overlook the fact that had inbreeding been present, it would actually have supported their hypothesis rather than have detracted from it. One does not preclude the. © 1985, Massachusetts Medical Society. All rights reserved.