Benign familial hematuria (BFH) also is known as benign persistent hematuria, benign essential hematuria, or thin basement membrane disease (TBMD). The term benign implies benign clinical course with good prognosis, and the term familial implies occurrence of hematuria in other family members.

BHF is a very common finding, occurring in more than 1% of the population. Affected individuals usually present with persistent or intermittent microscopic and occasionally gross hematuria. Hematuria usually is “dysmorphic” on phase contrast microscopy, with red cells of irregular size and shape. Proteinuria, progression to renal failure, or extrarenal symptoms such as hearing loss are not present. Physical examination is normal, and no abnormalities are noted with audiometric and ophthalmologic examinations. Laboratory studies reveal normal renal function and platelet count. Screening typically identifies hematuria in other family members, but these individuals fail to demonstrate hearing loss, renal failure, or proteinuria. Conversely, one-third of individuals with BFH may not have evidence of familial occurrence because the disease may be sporadic.

Renal biopsies from affected individuals are normal by light microscopy and immunofluorescence. Electron microscopy reveals the characteristic finding of focal or widespread thinning of the glomerular basement membrane (GBM), which is the hallmark of this disease, hence the term TBMD. However, these thin segments of GBM are not interspersed with segments of thick and split GBM typically seen in Alport syndrome.