PHENOTYPIC VARIATION IN COMBINED GRANULAR-LATTICE (AVELLINO) CORNEAL-DYSTROPHY

Objectives: To describe the phenotypic variation exhibited by members of families with combined granular-lattice (Avellino) corneal dystroph y. Setting: We examined 40 patients (age range, 12 to 85 years) from s ix unrelated families with Avellino corneal dystrophy. This included t he first individuals to ever be examined near the presumed site of ori gin in Italy. In addition, one family was the first to trace its origi ns to Germany rather than to Italy. We studied the phenotypic expressi on of the disease in the cornea, visual acuities, subjective complaint s, complications, treatment, and histologic condition of these individ uals. Results: The granular stromal lesions reach their mature quantit y and size early in life, and appear as either gray and crumb-shaped d eposits or superficial with an annular and planar distribution. The la ttice component appears gradually, beginning and maturing later in lif e. The phenotypic variation within families was found to be substantia l. Widely variable proportions of lattice and granular changes were fo und within single sibships. Visual acuities ranged from 20/20 to 20/40 0. Recurrent corneal erosions were present but infrequent. Subjective complaints included glare and decreased night vision. Penetrating kera toplasty was required in one individual to restore vision. Histopathol ogic examination revealed typical amyloid and granular deposits. Granu lar deposits were found replacing Bowman's membrane and extending to t he corneal surface. These deposits probably represent the cause of rec urrent erosions. Conclusions: Combined granular and lattice corneal dy strophy may present with substantial phenotypic variation. The disease can be found in individuals who trace their ancestry to both Italy an d Germany, a wider geographic distribution than previously proposed.