OCULAR ABNORMALITIES IN THIN BASEMENT-MEMBRANE DISEASE

Aim/background - Alport syndrome is an X linked disease that results i n renal failure, deafness, and ocular abnormalities including a dot an d fleck retinopathy and anterior lenticonus. The ultrastructural appea rance of the glomerular basement membrane in thin basement membrane di sease (TBMD) resembles that seen in some patients with Alport syndrome , and in some cases this disease is inherited too. The aim of this stu dy was to determine whether patients with TBMD have any ocular abnorma lities. Methods - The eyes of 17 unrelated individuals with TBMD were studied by slit-lamp, including biomicroscopic fundus examination with a 78 D lens, by direct ophthalmoscopy, and by fundal photographs. The findings were compared with those in patients with IgA glomerulonephr itis or Alport syndrome, and in normals.Results - No patient with TBMD had a dot and heck retinopathy or anterior lenticonus. A corneal dyst rophy (n = 2) or pigmentation (n = 1), and retinal pigment epithelial clumping and maculopathy (n = 1) were noted. Corneal, lens, and retina l dots were found in five (29%), three (18%), and 16 (94%) patients, r espectively, but these were also demonstrated in individuals with othe r renal diseases and in normal individuals. Conclusions - The dot and fleck retinopathy and anterior lenticonus typical of Alport syndrome d o not occur in TBMD. The protein abnormality and genetic defect in TBM D are not known, but the lack of ocular lesions suggests that the abno rmal protein in this disease is more sparsely distributed or less impo rtant in Australia the basement membranes of the eye than of the kidne y. Alternatively, the protein may be less affected by the mutations re sponsible for TBMD.