One family, with the R124C mutation, was diagnosed with lattice corneal dystrophy type 1, and the family with the H626R mutation was diagnosed with lattice corneal dystrophy type IIIB.
To report a phenotypic variant pedigree of lattice corneal dystrophy (LCD) associated with two mutations, R124C and A546D, in the transforming growth factor beta-induced gene (TGFBI).
For the three families, a single heterozygous c.371G>T (R124L) point mutation was found in exon 4 of TGFBI in 14 affected members with RBCD, a single heterozygous c.370C>T (R124C) point mutation was found in exon 4 of TGFBI in four affected members with LCDI, and a single heterozygous c.1877A>G (H626R) point mutation was found in exon 14 of TGFBI in four affected members with LCDI/IIIA.
All subjects recruited exhibited a range of corneal dystrophies, including Thiel-Behnke corneal dystrophy (TBCD, R555Q; 6 families and 4 individuals), granular corneal dystrophy type 2 (GCD2, R124H; 61 families and 80 individuals), lattice corneal dystrophy (LCD; 4 families and 5 individuals; 7 with type 1 [R124C], and 2 with a variant [L527R, P542R]).
Spontaneous mutations were detected in 2 families: an R124C mutation in 1 family with lattice corneal dystrophy (LCD) type I and an A546D mutation in the other with atypical LCD.
Avellino dystrophy has not previously been reported to be associated with the R124C mutation, which is usually associated with lattice corneal dystrophy.
In lattice corneal dystrophy (Arg124Cys and Leu527Arg mutations of TGFBI), highly reflective branching filaments of variable width were observed in the stroma.
Molecular genetic analysis identified a lattice corneal dystrophy I-associated heterozygous missense alteration (C417T) that changed arginine in codon 124 to cysteine (R124C) in the TGFBI gene.
The incidence of mutations was ranked as follows: 118 patients (72%), the R124H mutation associated with Avellino corneal dystrophy; 23 patients (14%), the R124C mutation associated with lattice corneal dystrophy type 1; and 10 patients (6%), the P501T mutation associated with lattice corneal dystrophy type 3A.
The heterozygous Arg124Cys mutation reported in Caucasian lattice corneal dystrophy caused severe lattice corneal dystrophy consisting of short and thin amyloid fibers in a Japanese family.