COL4A3 and hematuria, benign familial, 1: The differential diagnosis in 2012 for familial hematuria (FH) includes mostly the COL4A3/A4 heterozygous carriers that exhibit thin basement membrane nephropathy (TBMN) with lifelong microscopic hematuria [1]–[5] and a newly described disease, CFHR5 nephropathy, with isolated C3 mesangial deposits [6], [7].