Association Between Fuchs Endothelial Corneal Dystrophy, Diabetes Mellitus, and Multimorbidity

Prevalence and Economic Burden of Fuchs Endothelial Corneal Dystrophy in the Medicare Population in the United States

PURPOSE

The aim of this study was to assess the prevalence and economic burden of Fuchs endothelial corneal dystrophy (FECD) in patients older than 65 years in the United States.

METHODS

A retrospective analysis of the Medicare data reported to the Vision and Eye Health Surveillance System including patients diagnosed with FECD between 2014 and 2019 was performed. The crude prevalence rate of FECD was assessed and extrapolated to estimate the total case burden in the United States. The prevalence data were further compared between men and women and different racial groups. In addition, the economic burden was computed using inflation-adjusted direct costs of treatment to patients.

RESULTS

The Medicare database included 25,432,700 patients older than 65 years. The national prevalence of FECD in this population cohort was calculated to be 1.12% in 2019. In 2019, FECD case burden in Medicare patients older than 65 years was 284,846 and total estimated FECD case count in the country in this age group was 591,226. FECD prevalence was significantly higher in women as compared to men during the 6-year period evaluated in this study. The intergroup comparison revealed that FECD prevalence in the White population was significantly higher than all other racial groups ( P < 0.0001). The total inflation-adjusted economic burden of FECD in the United States in 2019 was USD 291.648 million and has increased from USD 243.998 million over the 6-year study period.

CONCLUSIONS

The estimated prevalence of FECD in the individuals older than 65 years is 1.12% in the United States. FECD prevalence is significantly higher in women and White population compared with other ethnicities.

A multi-ancestry GWAS of Fuchs corneal dystrophy highlights the contributions of laminins, collagen, and endothelial cell regulation

Fuchs endothelial corneal dystrophy (FECD) is a leading indication for corneal transplantation, but its molecular etiology remains poorly understood. We performed genome-wide association studies (GWAS) of FECD in the Million Veteran Program followed by multi-ancestry meta-analysis with the previous largest FECD GWAS, for a total of 3970 cases and 333,794 controls. We confirm the previous four loci, and identify eight novel loci: SSBP3, THSD7A, LAMB1, PIDD1, RORA, HS3ST3B1, LAMA5, and COL18A1. We further confirm the TCF4 locus in GWAS for admixed African and Hispanic/Latino ancestries and show an enrichment of European-ancestry haplotypes at TCF4 in FECD cases. Among the novel associations are low frequency missense variants in laminin genes LAMA5 and LAMB1 which, together with previously reported LAMC1, form laminin-511 (LM511). AlphaFold 2 protein modeling, validated through homology, suggests that mutations at LAMA5 and LAMB1 may destabilize LM511 by altering inter-domain interactions or extracellular matrix binding. Finally, phenome-wide association scans and colocalization analyses suggest that the TCF4 CTG18.1 trinucleotide repeat expansion leads to dysregulation of ion transport in the corneal endothelium and has pleiotropic effects on renal function.

Comparison of Scheimpflug and Anterior Segment Optical Coherence Tomography Imaging Parameters for Japanese Patients With Fuchs Endothelial Corneal Dystrophy With and Without TCF4 Repeat Expansions

PURPOSE

The aim of this study was to investigate the association between cytosine-thymine-guanine trinucleotide repeat (TNR) expansion in TCF4 and the clinical phenotypes of corneal densitometry or anterior segment morphology in Fuchs endothelial corneal dystrophy.

METHODS

This retrospective cross-sectional study included 150 eyes from 75 Japanese consecutive patients with Fuchs endothelial corneal dystrophy. Cytosine-thymine-guanine repeat expansion of leukocyte-derived genomic DNA was analyzed through fragment analysis using polymerase chain reaction and triplet repeat primed polymerase chain reaction. Scheimpflug-based densitometry and anterior segment optical coherence tomography were applied. Corneal densitometry, and corneal and anterior segment morphology parameters were compared between patients with and without TNR expansion of 50 or more (expansion and nonexpansion groups, respectively) using a mixed model.

RESULTS

The average age of the patients was 66.8 ± 13.0 years, and the modified Krachmer grading scale was 1, 2, 3, 4, 5, and 6 for 7, 32, 28, 51, 6, and 18 eyes, respectively. Sixteen patients (21%) exhibited ≥50 TNR expansion. No significant differences in sex, age, history of keratoplasty, modified Krachmer grade, and corneal densitometry in either diameter or depth were observed between the 2 groups. No significant differences in anterior segment morphology, including the anterior chamber depth and anterior chamber angle width parameters, were observed using a univariate mixed model, except for central corneal thickness (P = 0.047). However, according to the multivariate mixed model, repeat expansion was not significantly associated with central corneal thickness (P = 0.27).

CONCLUSIONS

No significant differences in clinical phenotypes were found between Japanese patients having Fuchs endothelial corneal dystrophy with and without TNR expansion.