Map-dot-fingerprint Dystrophy

Updated: May 21, 2014
  • Author: David D Verdier, MD; Chief Editor: Hampton Roy, Sr, MD  more...
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Overview

Background

Corneal map-dot-fingerprint dystrophy is by far the most common corneal dystrophy and is named from the appearance of its characteristic slit lamp findings. Map-dot-fingerprint dystrophy is also known as Cogan’s dystrophy, Cogan microcystic epithelial dystrophy, epithelial basement membrane dystrophy, and anterior basement membrane dystrophy. [1, 2, 3, 4, 5]

Historically, corneal dystrophies are usually described as hereditary, bilateral, progressive, and not associated with systemic or local disease. However, in most cases, map-dot-fingerprint dystrophy is not familial. [6] Map-dot-fingerprint dystrophy is also not progressive but rather variable and fluctuating in its course. In addition, map-dot-fingerprint dystrophy is usually bilateral, but it can be unilateral or very asymmetric in presentation. [7]

A new classification of corneal dystrophy has been proposed. According to the International Committee for Classification of Corneal Diseases (IC3D), corneal dystrophies are still classified by the anatomic layer of corneal involvement, but they are increasingly defined on a genetic basis. Map-dot-fingerprint dystrophy is placed in Category 4, which is "reserved for suspected new or previously documented corneal dystrophy, while the evidence for it being a distinct entity is not yet convincing." [8] Except for the few cases of map-dot-fingerprint dystrophy described in several families with a presumed autosomal dominant pattern, possibly coded on the TGFBI/BIGH3 gene, [9, 10] map-dot-fingerprint dystrophy might be more accurately categorized as a corneal degeneration.

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Pathophysiology

The corneal epithelium produces and adheres to its underlying basement membrane. Corneal abnormalities associated with map-dot-fingerprint dystrophy are the result of a faulty basement membrane, which is thickened, multilaminar, and misdirected into the epithelium. Deeper epithelial cells that normally migrate to the surface can become trapped. Epithelial cells anterior to aberrant basement membrane may have difficulty forming viable hemidesmosomes and basement membrane complexes, which attach to the underlying stroma, resulting in recurrent erosions. Irregular epithelium centrally can cause decreased vision.

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Epidemiology

Frequency

United States

Estimates of the prevalence of map-dot-fingerprint dystrophy range from 2-43% of the general population. Of patients with map-dot-fingerprint dystrophy, 10-33% have recurrent corneal erosions. As many as 50% of patients with recurrent corneal erosions have map-dot-fingerprint dystrophy. [11]

Mortality/Morbidity

Patients with map-dot-fingerprint dystrophy may be asymptomatic. Others experience painful recurrent erosions, decreased vision, or both. [12]

Sex

This condition is slightly more common in females than in males.

Age

This condition is uncommon in children.

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