Corneal dystrophy Thiel Behnke type

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.

Orpha Number: 98960

Definition

Thiel-Behnke corneal dystrophy (TBCD) is a rare form of superficial corneal dystrophy characterized by sub-epithelial honeycomb-shaped corneal opacities in the superficial cornea, and progressive visual impairment.

Epidemiology

Prevalence of this form of corneal dystrophy is not known. Cases have been reported in Germany, the USA and in other countries.

Clinical description

Corneal erosions develop in the first and second decade of life and cause ocular discomfort and pain. The erosions recur and vision gradually becomes impaired.

Etiology

Thiel-Behnke corneal dystrophy appears to be caused by mutation in the TGFBI gene (5q31), like Reis-Bücklers corneal dystrophy. However, there appears to be genetic heterogeneity as another locus has also been identified on chromosome 10 (10q23-q24).

Diagnostic methods

Histological examinations reveal a variable thickness of the corneal epithelium. The epithelial basal lamina and Bowman layer display variable degenerative changes. Irregular subepithelial collagenous tissue is also found.

Differential diagnosis

TBCD is clinically similar to Reis-Bücklers corneal dystrophy (RBCD, see this term), but generally has a less severe course. Tissue examination or molecular genetic analysis can be used to differentiate TBCD and RBCD.

Genetic counseling

This entity has an autosomal dominant mode of inheritance.

Management and treatment

The pathologic corneal tissue can be excised surgically or with an eximer laser.

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