Evidence for genetic heterogeneity in benign familial hematuria

Benign familial hematuria (BFH: MIM141200) is an autosomal-dominant disease accounting for one-fifth of at I hematuria of unknown cause in children. P revious observations suggest that BFH may be allelic to recessive Alport sy ndrome (AS: MIM 203780) with a mutation in the COL4A3/COL4A4 locus. However , it is not clear whether all cases of BFH are due to heterozygous mutation of COL4A3/COL4A4 genes. We report here the exclusion of linkage between BF H and CO L4A3/COL4A4 loci at 2q35-37 in a restricted population from Sicily (Italy), Total lod score is -9.6 at theta 0. Furthermore, in some cases ex clusion of linkage is evident even considering single families. We conclude that BFH is genetically heterogeneous.