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Definition / general | Site of damage and types of corneal dystrophy | Types of corneal dystrophy | Microscopic (histologic) images | Differential diagnosisCite this page: Pernick N. Corneal dystrophy. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/eyecorneadystrophy.html. Accessed April 1st, 2025.
Definition / general
- Heterogeneous group of inherited, bilateral, symmetric corneal disorders
- Most common is Fuchs dystrophy
- Also macular, lattice and granular corneal dystrophy
- Cause severe visual loss reparable by corneal transplantation
Site of damage and types of corneal dystrophy
- Epithelium:
- Meesman dystrophy
- Microcystic
- Map dot and fingerprint dystrophy
- Bowman layer and superficial stroma:
- Granular corneal dystrophy type III
- Thiel-Behnke dystrophy
- Familial subepithelial amyloidosis
- Stroma:
- Granular corneal dystrophy types I and II
- Macular corneal dystrophy
- Central stromal crystalline dystrophy
- Endothelium:
- Fuchs dystrophy (see below)
- Posterior polymorphous dystrophy
- Congenital hereditary endothelial dystrophy
Types of corneal dystrophy
- Central stromal crystalline dystrophy:
- Also called Schnyder corneal dystrophy
- Disease maps to 1p34-p32
- Crystals of cholesterol ester in anterior stroma
- Congenital hereditary endothelial dystrophy:
- Autosomal dominant (maps to 20q12-q13.1) or autosomal recessive
- Edematous epithelium with lack of Bowman layer
- Thickened stroma and Descemet membrane
- Diminished number of endothelial cells
- Familial subepithelial amyloidosis:
- Also called primary gelatinous droplike dystrophy
- Bowman layer and superficial stroma dystrophy
- Autosomal recessive
- Usually due to mutation in M1S1 gene at 1p
- Has subepithelial amyloid deposits that contain lactoferrin
- Fleck dystrophy:
- Also called speckled, cloudy dystrophy
- Subepithelial and stromal amyloid deposits
- Autosomal dominant
- Maps to 2q35
- Stains with colloidal iron and Alcian blue
- Granular corneal dystrophy type I:
- Stromal dystrophy
- Autosomal dominant
- Usually due to R555W mutation in TGFB1 gene at 5q31
- Discrete deposits of mutated protein appear red with Masson trichrome stain
- Granular corneal dystrophy type II:
- Also called Avellino corneal dystrophy
- Autosomal dominant
- Due to R124H mutation in TGFB1 gene at 5q31
- Corneal deposits similar to granular corneal dystrophy type I plus amyloid
- Granular corneal dystrophy type III:
- Also called Reis-Bucklers dystrophy
- Bowman layer and superficial stroma dystrophy
- Autosomal dominant
- Due to R124L mutation in TGFB1 gene at 5q31
- Lattice dystrophy:
- Irregular linear subepithelial and stromal amyloid deposits
- Normal Descemet membrane and endothelium
- Birefringent amyloid with Congo Red stain
- Lattice type I:
- Autosomal dominant
- Usually due to R124C mutation in TGFB1 at 5q31
- Lesions limited to cornea
- Often recurrent epithelial erosions and subepithelial amyloid or collagenous plaques
- Lattice type II:
- Autosomal dominant
- Mutation in GSN gene at 9q34
- Associated with familial amyloid polyneuropathy
- Amyloid is derived from fragment of mutated gelsolin
- Lattice type III:
- Autosomal recessive
- Amyloid deposits thicker than in types I and II
- Identity of amyloid unknown
- Lattice type IIIA:
- Autosomal dominant
- Amyloid deposits resemble type III
- Mutation in TGFB1 gene at 5q31
- Lattice type I:
- Macular corneal dystrophy:
- Autosomal recessive
- Due to mutation in CHST6 gene at 16q22.1
- Deficiency in carbohydrate sulfotransferase
- Causes deposits of low sulfated keratan sulfate related glycosaminoglycan throughout stroma
- Descemet membrane and endothelium
- Also corneal guttae
- Deposits are positive for colloidal iron and Alcian blue
- Macular type I:
- No / low serum keratan sulfate
- Keratocytes don't react to keratan sulfate antibodies
- Macular type IA:
- No / low serum keratan sulfate
- Keratocytes DO react to keratan sulfate antibodies
- Macular type II:
- Normal serum keratan sulfate
- Keratocytes DO react to keratan sulfate antibodies
- Macular type I:
- Meesmann dystrophy:
- Epithelium dystrophy
- Autosomal dominant
- Mutation in keratin KRT3 (12q) or KRT12 gene (17q)
- Intraepithelial microcysts
- Microcystic, map dot and fingerprint dystrophy:
- Epithelium dystrophy with nonspecific features
- Intraepithelial basement membrane and microcysts
- Posterior polymorphous dystrophy:
- Endothelial dystrophy
- Autosomal dominant (may be due to mutation in COL8A2 at 1p34.3-p32.3), or autosomal recessive
- May also map to 20q12-q13
- Abnormal Descemet membrane
- Has multilayered epithelial cells in posterior cornea
- Thiel-Behnke dystrophy:
- Transmission EM shows subepithelial "curly" fibers
- Due to R555Q mutation in TGFB1 gene at 5q31 or 10q23-q24
- Focal loss of epithelial basement membrane and Bowman layer
Differential diagnosis
- Amyloid due to trauma
- Glaucoma
- Keratoconus
- Retrolental fibroplasia
- Sympathetic ophthalmia
- Trachoma
- Uveitis