Clinical features and pathogenesis of Alport retinopathy.

BACKGROUND

Alport syndrome refers to the clinical triad of hereditary nephritis, sensorineural deafness, and ocular abnormalities. Ultrastructural findings in the lens capsule and in the renal glomeruli have provided evidence that abnormal basement membranes are elaborated in affected tissues of patients with this disorder. Recently, the results of several linkage studies have allowed the genetic defect in Alport syndrome to be mapped to a locus that codes for a subtype of type IV collagen (alpha 5) known to be present in glomerular basement membranes. In spite of these advances, the nature of the retinal flecks in Alport syndrome and the visual consequences of the flecks remain controversial.

METHODS

Detailed psychophysical and electrophysiologic testing was performed in a young man with Alport syndrome. The concurrence of an unusually extensive fleck retinopathy and unilateral pseudophakia afforded a unique opportunity to assess the effect of the flecks on retinal function.

RESULTS

No sensory deficits were present in the eye with clear media.

CONCLUSION

Macular flecks in Alport syndrome are not associated with demonstrable retinal dysfunction. The authors address questions about the nature and pathogenesis of the flecks in light of new clinical and genetic information.