Meesmann juvenile epithelial dystrophy

Genetics

AD Autosomal dominant (AD)

Mutation

Cytokeratin (CK) 3 or 12 (all epithelial cells contain intermediate filaments, the cytokeratins, in their cytoplasm).

CK3 forms a dimer with CK12, and this pair is regarded as a differentiation marker of the corneal epithelium of the ocular surface.

Laterality

Bilateral but sometimes asymmetric

Symmetry

Yes

Systemic factors

No

Age of onset

First years of life, with symptoms often appearing in adolescence

Location

epithelial cells only

Appearance:

• Direct illumination: diffuse grey opacities sparing the perilimbal region.
• Retroillumination: appearance of multiple clear, solitary cysts that are rarely refractile, due to cysts, vesicles or vacuoles within the epithelium.
• The cornea and stroma are clear.

The cysts consist of cytoplasmic and nuclear debris (granular and filamentous; "substance") contained within the cytoplasm of the epithelial cells, mainly the basal cells. There is thickening of the basement membrane and a high glycogen content in the basal epithelial cells. Keratin intermediate filaments play an important role in cellular architecture and in adhesion to the basement membrane.

Recurrent pain or erosions: These are due to recurrent punctate erosions. The erosions decrease with age.

This is a common symptom in recurrent erosion syndromes: pain is frequent at the onset of the condition and decreases as fibrosis of the anterior stroma develops.

Visual acuity: often preserved unless the cysts enlarge in front of the pupil.

Diagnosis:

• Confocal microscopy: hyporeflective zones resembling cysts at the level of the basal layer of the epithelium, then hyperreflective "cysts" within the more superficial layers of the epithelium.
• OCT: the epithelial thickness is irregular, the epithelium is globally hyperreflective, especially superficially, with fine hyperreflective punctate spots

Recurrence: yes