Increased Choroidal Thickness in Morquio Syndrome

Abstract

The purpose of this clinical case report is to describe a case of mucopolysaccharidosis type IVA (MPS IVA), or Morquio syndrome, with increased choroidal thickness in enhanced-depth imaging optical coherence tomography (EDI-OCT) which can represent choroidal deposition of glycosaminoglycans (GAGs). A 21-year-old male with genetically confirmed diagnosis of MPS IVA was examined at our Pediatric Ophthalmology clinic as part of our follow-up protocol for MPS patients. His best-corrected visual acuity was 4/10 in his right eye (OD) and 6/10 in the left eye (OS). Mild diffuse corneal opacification was evident. Intraocular pressure was within normal range. Fundus examination and color fundus photography revealed no abnormalities. EDI-OCT revealed significantly increased choroidal thickness in his right eye and in his left eye, suggesting the presence of choroidal deposition of GAGs, despite absence of retinal or optic disc GAG deposition or other chorioretinal involvement. To our knowledge, this is the first case of MPS IVA described in the literature with suspected choroidal deposition of GAGs. With improved control of systemic features of MPS IVA, life expectancy of these patients has increased, allowing for more ocular manifestations to develop. The parallel development of technology in ophthalmology, such as the EDI-OCT, further contributes to the detection of these unprecedented ocular features in MPSs.