A Novel Phenotype of Avellino Corneal Dystrophy

Abstract

Abstract: : Purpose: Avellino corneal dystrophy classically presents with three distinct clinical features; discreet superficial gray-white granular deposits (hyaline), deeper stromal latticular to stellate lesions (amyloid), and in later stages stromal haze (amyloid). The purpose of this report was to describe a novel phenotype of Avellino corneal dystrophy which combined features of classic Avellino with findings characteristic of lattice corneal dystrophy type IV or polymorphic amyloid degeneration. Methods: Histopathologic examination was performed on a corneal button obtained from the left eye of a 35-year-old African-American female who presented with a clinically unusual corneal dystrophy. Results: Slit-lamp exam revealed bilateral, symmetric, central stromal opacities composed of radially arranged dichotomously branching refractile lines which radiated from a central stromal haze. Distinct from these lesions were a cluster of very deep, small, polymorphic, refractile deposits which indented Descemet's membrane into the anterior chamber. No discreet superficial granular deposits were identified. Histologically, amyloid was identified by Congo red stain in the anterior and mid-stromal regions, along with focal deposits of hyaline as determined by Mason's trichrome. In addition, very deep amyloid deposits were identified indenting Descemet's membrane. Conclusions: The histopathologic identification of both hyaline and amyloid deposits confirmed this patient's diagnosis of Avellino corneal dystrophy. Phenotypically however, this dystrophy was unique in the following respects; lack of clinically observable granular lesions, the chronic premature stromal haze, and the distinctively deep amyloid desposits previously identified only in a much older patient population (60-70s) which have been labeled either lattice corneal dystrophy type IV or polymorphic amyloid degeneration. These observations further expand the phenotypic spectrum encompassed by the appellation Avellino corneal dystrophy.

Keywords: cornea: clinical science • pathology: human • genetics