Abstract
Purpose:
To report the clinical and molecular findings in Polish patients with corneal dystrophies caused by TGFBI gene mutations.
Methods:
Patients with clinically diagnosed corneal dystrophies (n=26; 18 unrelated families) participated in the study. Corneal phenotypes were assessed by slit lamp and confocal microscopy in vivo. Genomic DNA was obtained from blood samples and exons 4, 11-14, known to contain mutation hot spots, were PCR amplified and sequenced on both strands.
Results:
Molecular genetic testing revealed a heterozygous R555W (exon 12) mutation in fifteen (9 families) patients diagnosed with granular corneal dystrophy type I (GCD type I). In one patient a heterozygous R124H (exon 4) mutation, typical for granular-lattice corneal dystrophy (GCD type II) was found. In three patients (2 families) clinically diagnosed of having Reis-Buecklers corneal dystrophy a heterozygous R124L mutation, commonly found in patients with this type of corneal dystrophy, was identified (GCD type III). In two patients (2 families) a heterozygous R555Q (exon 12) mutation typical for Thiel-Behnke corneal dystrophy was detected. Heterozygous R124C (exon 4), T538R (exon 12) and H626R (exon 14) mutations were identified, respectively, in three patients (3 families) diagnosed with lattice corneal dystrophy (LCD type I). In two patients from one family presenting a phenotype of granular-lattice corneal dystrophy the R124C mutation, typically identified in patients with LCD type I, was found.
Conclusions:
In the analyzed group of Polish patients with corneal dystrophies TGFBI gene mutations are located exclusively in the major mutational hotspots. Noteworthy, patients with GCD type I, representing the most predominant type of corneal dystrophy in the analyzed group (9/18 families, 50%), were all carriers of the same R555W mutation. The results of our study indicate that a relatively straightforward molecular analysis can be a practical use in diagnosis of these conditions and associated genetic counseling.
Keywords: 479 cornea: clinical science •
539 genetics