Axenfeld-Rieger syndrome: a novel histopathologic finding associated with corneal abnormalities

BACKGROUND: Axenfeld-Rieger syndrome (ARS) is a rare kind of anterior segment dysgenesis (ASD). The most common ocular features of ARS are posterior embryotoxon and iris hypoplasia, while some patients may manifest as corneal opacity and edema. However, the current understanding of how ARS affects the cornea is still incomplete. This study reports a novel histopathological finding of ARS, complicating corneal abnormalities, including congenital corneal opacity and irreversible endothelial decompensation. METHODS: This retrospective study included 6 eyes of 3 ARS patients, 5 of which underwent keratoplasty for irreversible endothelial decompensation from May 2016 to January 2019. No eye had a history of surgery. We reviewed the data of epidemiology, clinical manifestations and histopathologic examinations. RESULTS: Five eyes developed irreversible endothelial decompensation, among which 4 were born with corneal opacity. One eye exhibited transparent cornea but showed a continuous loss of endothelial cells in the absence of surgery and elevated intraocular pressure thereafter. Anterior segment optical coherence tomography photographs showed that anterior synechia existed in the area with corneal opacities, where we found the interlayer splitting of the Descemet membrane inserted by hypoplastic iris and a basement membrane-like structure under a light microscope. CONCLUSION: Anterior synechia might be associated with corneal abnormalities in ARS patients. The novel histopathologic finding revealed the internal relation between anterior segment dysgenesis and would help explore the inner mechanism of corneal abnormalities in ARS.