Lab Invest 1986 Nov;55(5):564-72

Nephronophthisis. A primary tubular basement membrane defect

Cohen AH, Hoyer JR

Abstract
In order to characterize abnormalities in nephronophthisis, renal tissues from
four patients were studied by light and electron microscopies and
immunofluorescence using antibodies to laminin, type IV collagen, and tubular
basement membranes (TBM). There were constant morphological alterations
affecting TBM of all segments of the nephron, with or without cysts. These
included extreme thinning and attenuation, layering, and thickening of these
structures which ranged in size from 36 nm to 2000 nm. A combination of these
features often affected the same TBM simultaneously, with abrupt transitions
between different lesions. Although the ultrastructural TBM aberrations were
observed in a wide variety of other chronic and acute renal disorders, they
rarely occurred to the extent as in nephronophthisis or with abrupt transitions,
both suggesting diagnostic significance. Laminin and type IV collagen were
present in normal intensity and distribution, however, anti-TBM antibody
staining was inconstantly reduced, perhaps signifying lack of a normal antigenic
component in the TBM. These findings may well indicate the fundamental defect in
nephronophthisis to be production of abnormal TBM, similar to the glomerular
basement membrane lesions and consequences in Alport's syndrome