LAUSR

PURPOSE To report the anterior segment clinical features as well as histopathologic and histochemical characteristics of corneal findings associated with 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 SETTING: Institutional PATIENT OR STUDY POPULATION: 15 corneas from 9 patients with MPS-I spectrum disease who underwent corneal transplant to treat corneal clouding between May 2011 and October 2020. INTERVENTION OR OBSERVATION PROCEDURE(S) Review of clinical data, hematoxylin and eosin (H&E) stained sections and histochemical stains, including those for mucopolysaccharides (Alcian blue and/or collodial iron). MAIN OUTCOME MEASURE(S) Pathology observed under light microscopy, as well as, post-surgical clinical outcomes. RESULTS Nine patients underwent fifteen corneal transplants for corneal clouding (14/15 procedures were deep anterior lamellar keratoplasty). All corneas had mucopolysaccharide deposition visible on H&E stained 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 which 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 H&E 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.