Mucopolysaccharidosis Type I-Associated Corneal Disease: A Clinicopathologic Study

Am J Ophthalmol. 2021 Nov;231:39-47. doi: 10.1016/j.ajo.2021.05.014.

PMID: 34048802

Imani M Williams, Roberto Pineda, Vamsee K Neerukonda, Anna M Stagner

Highlights: Excised corneas of MPS I patients show characteristic epithelial changes, disruption or breaks in Bowman's membrane, and amphophilic collections of stromal granular mucopolysaccharides. These changes should alert the pathologist to the possibility of an underlying lysosomal storage disorder.

Abstract

Purpose: To report the anterior segment clinical features and histopathologic and histochemical characteristics of explanted corneas from the largest reported cohort of patients with Hurler syndrome and other variants of mucopolysaccharidosis (MPS) I undergoing corneal transplantation

Design: Retrospective observational case series.

Methods: This institutional study reviewed 15 corneas from 9 patients with MPS I spectrum disease who underwent corneal transplant to treat corneal clouding between May 2011 and October 2020. The clinical data, hematoxylin-eosin-stained sections, and histochemical stains, including those for mucopolysaccharides (Alcian blue and/or colloidal iron) was reviewed. The main outcome measures were pathology observed under light microscopy and postsurgical clinical outcomes.

Results: Nine patients underwent 15 corneal transplants for corneal clouding (14/15 procedures were deep anterior lamellar keratoplasty). All corneas had mucopolysaccharide deposition visible on hematoxylin-eosinstained sections, which was highlighted in blue with histochemical stains. All corneas also showed alterations in Bowman's layer and the majority also showed epithelial abnormalities.

Conclusion: MPS I shows significant corneal clouding that is successfully treated with deep anterior lamellar keratoplasty. The excised corneas show characteristic epithelial changes, disruption or breaks in Bowman's membrane, and amphophilic collections of stromal granular mucopolysaccharides which are visible on hematoxylin-eosin-stained sections and highlighted by special histochemical stains (Alcian blue and collodial iron). These changes, although subtle, should alert the pathologist to the possibility of an underlying lysosomal storage disorder.

Keywords: MPS, Corneal Diseases, Corneal Surgery, Corneal Transplantation, Mucopolysaccharidosis type I