We report, for the first time, atypical granular corneal dystrophy type 2 with cornea guttata associated with a single R124H mutation in a Chinese family.
It is our intention to demonstrate that the pre-operative genetic screening for TGFBI mutations should be mandatory for refractive surgery candidates.Patients and MethodsIn this study, we reviewed the proband's post-LASIK slit-lamp and in vivo confocal microscopy images and genetic testing results, and performed genetic testing on eleven additional members of the family to investigate the penetrance of corneal dystrophy in asymptomatic members who carry the mutation.ResultsThe proband demonstrated a post-LASIK exacerbation of Granular Corneal Dystrophy type 2 (GCD2), identified as a TGFBI R124H mutation.
Screening for the TGF β-induced gene found the heterozygous p.R124H mutation associated with granular corneal dystrophy type 2 in each of the 4 individuals with corneal opacities as well as in a fifth individual who did not have any corneal opacities, for a prevalence of 0.24%.
One mutation, generating an arginine to histidine amino acid substitution at position 124 in mature TGFBIp leads to granular corneal dystrophy type 2 (GCD2).
Granular corneal dystrophy type 2 (GCD2) is an autosomal dominant disease caused by a R124H point mutation in the transforming growth factor-β-induced gene (TGFBI).
We describe the phenotypic range of GCD2 heterozygotes for the common R124H mutation in TGFBI; seven with an extremely mild phenotype and six with an extremely severe phenotype.
Primary culture corneal fibroblasts were isolated from the corneas of healthy subjects and patients with granular corneal dystrophy type 2 (GCD2) with a homozygous mutation in TGFBI R124H.
Genetic examination identified that two ACD subjects were associated with homozygous R124H mutation of TGFBI, and four LCD I subjects were all associated with R124C heterozygous mutation.
Both granular and lattice deposits are present in Avellino corneal dystrophy (ACD), primarily associated with the R124H mutation of transforming growth factor-β-induced (TGFBIp).
The finding of R124H in the Middle Eastern (Iranian) population supports the proposal that perhaps only substitution of histidine for arginine at position 124 of tumour growth factor beta induced protein results in the Avellino corneal dystrophy phenotype.
Avellino corneal dystrophy (ACD) is a common corneal dystrophy that shows allelic homogeneity, R124H mutation in the transforming growth factor beta-induced (TGFBI) gene.
In Avellino corneal dystrophy (Arg124His mutation of human transforming growth factor beta-induced gene [TGFBI]), highly reflective granular materials with irregular edges were observed in the superficial stroma.
In exon 4, an R124H mutation associated with Avellino corneal dystrophy (ACD) was found in 39/44 families (86.4%) and an R124C mutation associated with lattice corneal dystrophy type 1 (LCD1) was detected in 2/44 families (4.5%).
Six patients with Avellino corneal dystrophy (ACD) associated with R124H, one patient with superficial granular corneal dystrophy (SGCD) associated with R124L, and seven patients with lattice corneal dystrophy type 1 (CDL1) associated with R124C were examined.