[citation needed] The molecular basis for thin basement membrane disease has yet to be elucidated fully; however, defects in type IV collagen have been reported in some families.

[4] Thin basement membrane disease must be differentiated from the other two common causes of glomerular hematuria, IgA nephropathy and Alport syndrome.

The history and presentation are helpful in this regard:[citation needed] A kidney biopsy is the only way to diagnose thin basement membrane disease.

The prognosis is excellent in this setting unless the clinical manifestations progress, as occurs in most males and some females with Alport syndrome and many patients with IgA nephropathy.

[citation needed] The molecular basis for thin basement membrane disease has yet to be elucidated fully; however, defects in the gene encoding the a4 chain of type IV collagen have been reported in some families.