Prevalence and severity of fuchs corneal dystrophy in Tangier Island.

PURPOSE: To investigate the clinical and genetic features of late-onset Fuchs corneal dystrophy (FCD) on Tangier, an island in the Chesapeake Bay with an isolated population of approximately 500 individuals.
DESIGN: Observational, cross-sectional study.
METHODS: A total of 156 individuals born to inhabitants of Tangier Island volunteered to undergo ophthalmic evaluation. Medical history was ascertained prior to examination. All participants underwent anterior segment examination with slit-lamp biomicroscopy. Retroillumination photographs were acquired from affected individuals and the disease severity was compared with individuals from large families ascertained previously. Genomic DNA samples were investigated for the presence of the recently identified risk allele rs613872, an intronic variant of TCF4.
RESULTS: Of the 148 examined individuals who were at least 30 years of age, 32 showed the classical symptoms of late-onset FCD (21.6%), providing a minimum prevalence of 11% among individuals over the age of 50 years. Severity was significantly lower compared to 51 cases from unlinked families, among individuals either 50 to 70 or above 70 years of age (P = .05 and P = .01, respectively). Retroillumination photography analyses were suggestive of mild severity when compared with the disease phenotype associated with FCD1- and FCD2-linked families. The rs613872 variant was associated with a higher affectation rate (P = .01), while the wild-type allele was correlated with a higher proportion of subclinical disease (P = .01).
CONCLUSIONS: In this study population in Tangier, late-onset FCD manifests clinically with a mild phenotype and increased prevalence. The rs613872 variant correlates with increased affectation and a clinical disease phenotype.