Clinical ocular manifestations of Taiwanese patients with mucopolysaccharidoses VI (Maroteaux-Lamy syndrome)

Abstract

Mucopolysaccharidoses (MPS) is a group of lysosomal storage disorders that lead to accumulation of glycosaminoglycans (GAGs) in many tissues and organs, resulting in different clinical features. In this study, we conducted the manifestation changes of refractive error, corneal clouding, and intraocular pressure in two Taiwanese MPS VI patients with enzyme replacement therapy (ERT) initiated at the age of eight. In case 1, hyperopia was noted before and after ERT. Clinical observation showed no significant improvement in corneal clouding after ERT. In case 2, hyperopia was also noted initially before ERT and unable to be measured due to severe corneal opacity. Clinical observation showed no significant improvement in corneal clouding in after ERT, and the best-corrected visual acuity worsen and keratoplasty was needed in both eyes. Case 2 also had ocular hypertension and suspect MPS VI-related. However, due to severe corneal clouding, optic disc changes were hard to examine, and visual field was unable to be tested. Although some literature shows that ERT may be effective in preventing and/or clearing corneal stromal GAGs, accumulation and the timing of treatment initiation cloud be a clinical prognosis predictor; in this experience, no significant improvement of corneal clouding was observed in patients with MPS IV after ERT. Hyperopia and glaucoma were noted, and showed no changes after ERT. Severe corneal clouding can lead to difficulties in diagnosis and monitoring of hyperopia and glaucoma.

Keywords: Corneal clouding; enzyme replacement therapy; mucopolysaccharidosis VI; refractive error.