Lens capsule abnormalities in Alport's syndrome.

The ultrastructure of the glomerular basement membrane in Alport's syndrome is well known and characteristic of this disease, but the anterior lenticonus that frequently occurs in this syndrome has not been similarly studied. An anterior lens capsule from a 30-year-old patient with lenticonus who had Alport's syndrome was obtained at capsulectomy and found to be one third the normal thickness centrally and to be more fibrillar than usual. There were large numbers of partial capsular dehiscences containing fibrillar material and vacuoles. Cellular debris and more recent ruptures of lens epithelial cell membranes underlaid the breaks. The anterior capsule is clearly fragile in this disease, forming the basis for the progressive lenticonus and anterior polar cataract. These abnormalities correlate well with a defect in the type IV collagen molecule, as has been recently reported in Alport's syndrome.