Abstract
Purpose:
To present the results of clinical and genetic analysis in a group of Mexican patients with stromal corneal dystrophies.
Methods:
Diagnosis of corneal dystrophy was confirmed by specialized ophthalmologic clinical examination. Molecular analysis included PCR amplification and automated direct sequencing of the complete coding region of TGFBI, CHST6 and Gelsolin genes.
Results:
A total of 20 Mexican patients (13 females/ 7 males) ranging from 26 to 75 years of age, pertaining to 9 different families were included. Ten patients from 5 distinct pedigrees were clinically diagnosed with lattice corneal dystrophy, 3 patients from 2 different pedigrees with granular corneal dystrophy type 2 (or Avellino), 2 unrelated probands were classified as Finnish type corneal amyloidosis (or lattice type 2), and 1 subject was clinically diagnosed with macular corneal dystrophy. Seven affected subjects from 4 out of 5 families diagnosed with lattice corneal dystrophy were shown to carry a heterozygous c.1877A>G mutation in exon 14 of the TGFBI gene, predicting a histidine to arginine change at codon 626 (p.H626R). Three affected subjects from the remaining lattice dystrophy family were shown to carry a heterozygous c.370C>T mutation in TGFBI exon 4, predicting a p.R124C mutation. Two subjects from a family with granular type 2 corneal dystrophy showed a heterozygous p.H626R mutation. Affected subjects from another granular type 2 corneal dystrophy pedigree carried a heterozygous c.1856T>A mutation in exon 14 of TGFBI, predicting a p.M619K substitution. Molecular analysis of the GSN gene in 2 unrelated probands with Finnish type corneal amyloidosis revealed a heterozygous c.654G>A transition in one of them, which predicts a p.D187N substitution. No GSN mutations were identified in the second unrelated proband with this diagnosis. Molecular analysis of the CHST6 gene in 1 patient clinically diagnosed with macular corneal dystrophy showed a homozygous c.328T>C transition, predicting a p.Y110C change.
Conclusions:
Three genes, TGFBI, CHST6, and GSN, previously implicated in the disease, were screened in a group of Mexican patients. A total of 5 different mutations were demonstrated in these 3 genes, broadening our current knowledge of the mutational spectrum associated with stromal corneal dystrophies in our country.
Keywords: 480 cornea: basic science •
539 genetics