EXCLUSION OF 8 GENES AS MUTATED LOCI IN CONGENITAL NEPHROTIC SYNDROMEOF THE FINNISH TYPE

The congenital nephrotic syndrome of the Finnish type (CNF) is an auto somal recessive disease characterized by massive proteinuria already a t birth. The gene locus defective in CNF was searched for using polymo rphic markers of candidate genes coding for components of the basement membrane (BM). The linkage analyses in 17 Finnish CNF families demons trated exclusion or obligatory recombination events between the diseas e and eight genes coding for BM components. The genes coding for the a lpha 1(IV), alpha 2(IV), alpha 3(IV) and alpha 4(IV) chain of type IV collagen, the B1e, B2e and B2t chains of laminin, as well as the BM he paran sulfate proteoglycan core protein were all excluded in this Finn ish family material. Since the defect is not in any of the genes codin g for major components of BM, the identification of the gene defect wi ll most probably reveal a new gene important for the development and f unction of the glomerular basement membrane.