A triad of retinal signs in Alport syndrome: The ‘stair-case’ fovea,choroidal thinning and peripheral schisis

Abstract

Background:

Alport syndrome is an inherited Type IV collagenopathy characterised by renal failure, hearing loss and ophthalmic manifestations such as lenticonus and dot-and-fleck retinopathy. New signs have been described which can be useful both for diagnosis and for prognosticating the risk of complications. This study examines and describes a triad comprising the unusual ‘stair-case’ foveal sign, together with choroidal thinning and late-stage peripheral schisis in a patient with Alport syndrome.

Case presentation:

This is a case report of a 49-year-old Caucasian male with a background of X-linked Alport syndrome presenting with gradual and progressive diminution of vision in the left eye with a central blur. He had already undergone three renal allografts, was deaf and suffered from hypertension by the time of his first presentation to ophthalmology. On examination, corrected visual acuity was 6/9.5 in the right eye and 6/30 in the left eye. Optical coherence tomography imaging showed an unusual ‘stair-case’ sign of the fovea in both eyes, together with choroidal thinning. We postulate that an abnormal vitreomacular interface followed by vitreomacular traction and eventually separation, removing layers of the inner retina with the vitreous, led to this unusual appearance. Subsequently, this patient also developed schitic changes more peripherally in the retina which progressed over the following 5 years.

Conclusion:

The stair-case foveal sign, choroidal thinning and mid-peripheral schisis are three signs that clinicians might expect to encounter on optical coherence tomography imaging of patients with Alport syndrome. These findings can be attributed to unique mutations of collagen IV which lead to a variety of clinical phenotypes affecting basement membrane structures. Identification of these features may not only be useful diagnostically and in forecasting complications such as macular holes, but also predict mode of inheritance and likelihood of early-onset renal failure.