Ocular manifestations as key features for diagnosing mucopolysaccharidoses

Diagnosis of mucopolysaccharidosis (MPS) requires awareness of the multisystem disease manifestations and their diverse presentation in terms of time of onset and severity. Many patients with MPS remain undiagnosed for years and progressively develop irreversible pathologies, which ultimately lead to premature death. To foster timely treatment and ensure a better outcome, it is of utmost importance to recognize and evaluate the typical ocular features that present fairly early in the course of the disease in many children with MPS. These include corneal clouding, ocular hypertension/glaucoma, retinal degeneration, optic disc swelling and optic nerve atrophy. Other associations include pseudo-exophthalmos, amblyopia, strabismus and large refractive errors requiring spectacle correction. While some ocular manifestations require specialized equipment for detecting abnormalities, light sensitivity, pseudo-exophthalmos and strabismus are often apparent on a routine physical examination. In addition, patients may be symptomatic from vision impairment, photosensitivity, night blindness and visual field constriction. Combined with the skeletal/joint complications and other manifestations, these ocular features are key in the differential diagnosis of children with joint abnormalities. Rheumatologists should have a high index of suspicion for MPS to facilitate early diagnosis. Referral to a geneticist, a metabolic specialist or physician who specializes in MPS can confirm the diagnosis and provide disease management. Consultation with an ophthalmologist who has expertise in MPS is also needed for thorough examination of the eyes and regular follow-up care.