REIS-BUCKLERS CORNEAL DYSTROPHY
GRANULAR CORNEAL DYSTROPHY, TYPE III
CORNEAL DYSTROPHY, GEOGRAPHIC
CORNEAL DYSTROPHY, REIS-BUCKLERS TYPE
CDRB
CDB1
RBCD
Superficial granular corneal dystrophy
Atypical granular corneal dystrophy
Geographic corneal dystrophy
Anterior limiting membrane dystrophy type I
Granular corneal dystrophy type III
Corneal dystrophy of Bowman layer type I
Paufique and Bonnet (1966) described a family with members in 3 generations affected by Reis-Buckler corneal dystrophy. Most of the affected persons also had strabismus. The cornea presented a 'dusty' opacity and a rough map-like surface with a ... Paufique and Bonnet (1966) described a family with members in 3 generations affected by Reis-Buckler corneal dystrophy. Most of the affected persons also had strabismus. The cornea presented a 'dusty' opacity and a rough map-like surface with a peripheral condensation ring separated from the limbus by a narrow strip of normal cornea. The lesions are primarily in Bowman membrane with secondary involvement of the epithelium and superficial part of the stroma. Relapsing corneal erosions occur between ages 8 and 20 and again in more severe form at about 40 or 50 years. The ultrastructure was described by Rice et al. (1968) and Akiya and Brown (1971). Almost every epithelial cell, but especially the basal cells, showed degenerative changes, i.e., swollen mitochondria, large vacuoles, swelling and disruption of the endoplasmic reticulum. Bowman membrane was almost completely replaced by masses of disoriented collagen fibrils and smaller electron-dense fibrils whose composition and origin have not been determined. Moller (1989) concluded that Reis-Bucklers corneal dystrophy may be the same entity as Groenouw type I granular corneal dystrophy. To clarify whether Thiel-Behnke corneal dystrophy is a separate entity from Reis-Bucklers corneal dystrophy, Kuchle et al. (1995) examined 28 corneal specimens with a clinically suspected diagnosis of corneal dystrophy of the Bowman layer by light and electron microscopy and reviewed the literature. Eight specimens came from patients with a honeycomb-shaped pattern of opacities at the level of the Bowman layer. Study of these 8 specimens disclosed destruction of Bowman layer, a subepithelial fibrocellular tissue with an undulant configuration, absence of the epithelial basement membrane in many areas, and the presence of 'curly' collagen fibers with a diameter of 9 to 15 nm. Kuchle et al. (1995) concluded that 2 distinct autosomal dominant CDBs exist and proposed the designation CDB type I (geographic or 'true' Reis-Bucklers dystrophy) and CDB type II (honeycomb-shaped or Thiel-Behnke dystrophy). Eight corneas were characterized as CDB type II. Visual loss is significantly greater in CDB I, and recurrences after keratoplasty or keratectomy seem to be earlier and more extensive in CDB I. Most cases previously reported as Reis-Bucklers dystrophy were thought by Kuchle et al. (1995) to be CDB II. Kobayashi and Sugiyama (2007) used in vivo laser confocal microscopy to investigate microstructures in patients with genetically confirmed Thiel-Behnke or Reis-Bucklers corneal dystrophy. In the Thiel-Behnke type, the deposits in the epithelial basal cell layer showed homogeneous reflectivity with round edges accompanying dark shadows. In contrast, deposits in the Reis-Bucklers type in the same cell layer showed extremely high reflectivity from small granular materials without any shadows in all cases. In each dystrophy, the Bowman layer was replaced totally with pathologic materials; the reflectivity of those materials is much higher in the Reis-Bucklers type than in the Thiel-Behnke type.
In 6 families with various forms of corneal dystrophy, Munier et al. (1997) identified missense mutations in the TGFBI gene. All the mutations occurred at the CpG dinucleotide of 2 arginine codons: arg555 to trp (R555W; 601692.0001) in ... In 6 families with various forms of corneal dystrophy, Munier et al. (1997) identified missense mutations in the TGFBI gene. All the mutations occurred at the CpG dinucleotide of 2 arginine codons: arg555 to trp (R555W; 601692.0001) in a family with CDGG1, arg555 to gln (R555Q; 601692.0002) in a family with CDTB, arg124 to cys (R124C; 601692.0003) in 2 families with CDL1, and arg124 to his (R124H; 601692.0004) in 2 families with ACD. The observations established a common molecular origin of several 5q31-linked corneal dystrophies. The family with CDTB was initially described as having Reis-Buckler corneal dystrophy, but in a later report (Munier et al., 2002) the phenotype was reclassified as CDTB. Okada et al. (1998) described an arg124-to-leu mutation (R124L; 601692.0007) mutation in a 25-year-old man with progressive subepithelial geographic opacities of the cornea. This was thought to be an example of 'true' Reis-Bucklers corneal dystrophy with geographic opacities rather than honeycomb-shaped opacities (CDTB). Kim et al. (2002) studied the molecular properties of wildtype and mutant BIGH3 proteins: specifically, the R124L (CDRB), R124C (CDL1), R124H (ACD), R555W (CDGG1), and R555Q (CDTB) mutations commonly found in 5q31-linked corneal dystrophies. They found that the mutations did not significantly affect the fibrillar structure, interactions with other extracellular matrix proteins, or adhesion activity in cultured corneal epithelial cells. In addition, the mutations apparently produced degradation products similar to those of wildtype BIGH3. BIGH3 polymerizes to form a fibrillar structure and strongly interacts with type I collagen (see 120150), laminin (see 150320), and fibronectin (135600). Tanhehco et al. (2006) reported 2 unrelated cases of Reis-Bucklers corneal dystrophy caused by spontaneous mutations in the TGFBI gene. Both children had had multiple corneal erosions, and neither had a family history of corneal dystrophy. Analysis of the TGFBI gene identified the R124L mutation in both children. The mutation was not found in any of the parents.