Corneal endothelial assessment in xeroderma pigmentosum: a case-control study

Area of Science:

• Ophthalmology
• Genetics
• Cell Biology

Background:

• Xeroderma pigmentosum (XP) is a rare genetic disorder characterized by defective DNA repair, leading to increased sensitivity to UV radiation.
• Ocular manifestations in XP can include photophobia, ectropia, and corneal involvement, although clear corneas are sometimes observed.

Purpose of the Study:

• To compare corneal endothelial cell population, morphology, and irregularity in patients with xeroderma pigmentosum (XP) and clear corneas against age- and sex-matched healthy controls.
• To analyze differences in endothelial cell density, cell area, and cell area variation using specular microscopy.

Main Methods:

• A case-control study involving nine patients with XP (without corneal involvement) and nine healthy controls matched for age and sex.
• Corneal endothelial layers were evaluated using specular microscopy to assess cell density, maximum and minimum cell areas, and coefficient of variation of cell areas.

Main Results:

• Patients with XP exhibited significantly lower endothelial cell density (P < 0.002) and significantly higher maximum and minimum cell areas (P < 0.016 and P < 0.029, respectively) compared to controls.
• No statistically significant differences were found in the coefficient of variation of cell areas between the XP group and controls.
• Central corneal thickness was slightly higher in controls, but this difference was not statistically significant (P = 0.106).

Conclusions:

• Endothelial cell population can be decreased in patients with xeroderma pigmentosum, even in the absence of apparent corneal disease.
• Specular microscopy reveals distinct changes in corneal endothelial cell morphology in XP patients, including reduced cell density and altered cell size distribution.
• While cell density is affected, other parameters like coefficient of variation and central corneal thickness may remain within normal limits, suggesting a specific impact on endothelial cell population in XP.