Posterior polymorphous dystrophy of the cornea. An ultrastructural study

Area of Science:

• Ophthalmology
• Developmental Biology
• Histopathology

Background:

• Congenital posterior polymorphous dystrophy (PPCD) is a rare inherited corneal disease.
• It affects Descemet's membrane and the corneal endothelium.
• Early-onset PPCD is unusual, prompting investigation into developmental origins.

Observation:

• Electron microscopy examined a corneal button from a 2-month-old infant with PPCD.
• The posterior cornea was lined by irregularly arranged, multilayered cells with epithelial features, not endothelium.
• Descemet's membrane showed focal alterations affecting multiple layers.

Findings:

• Abnormal epithelial-like cells were identified in place of the corneal endothelium.
• Significant alterations in Descemet's membrane were observed.
• These pathological features were present in a very young infant.

Implications:

• The findings suggest PPCD may have an early intrauterine onset.
• Disease onset could coincide with the initiation of Descemet's membrane development.
• This provides insights into the developmental pathology of PPCD.