Uninterrupted microscopic hematuria is present from birth in affected males. Urinary RBCs are dysmorphic, and RBC casts can usually be found. Heterozygous females are generally much less severely affected. Around one fifth of them will develop ESRD after the age of 50. 18. The families with early onset of renal failure in males are termed juvenile and those with renal failure in middle age are called adult type nephritis.
Extrarenal manifestations tend to be more prominent in the juvenile kindreds.
In families with juvenile type disease, hearing loss is almost universal in male hemizygotes and common in severly affected female heterozygotes. BFH is a genetically heterogeneous condition and it is usually autosomal dominant disease. Lemmink et al. In a large Dutch BFH kindred, the disease locus was mapped to chromosome 2 in the region of COL4A3 and COL4A4 genes. A pathogenic mutation in the COL4A4 was identified.