Corneal Manifestation in Patients with Infantile Nephropathic Cystinosis

Nephropathic cystinosis is a rare autosomal recessive disease caused by mutations in the CTNS gene. This causes dysfunction of cystinosin, a protein that transports cystine out of lysosomes, causing cystine crystals to accumulate in cells in most organ systems. While renal complications predominate in the early forms of cystinosis, corneal crystal accumulation will inevitably manifest in all patients. The main symptoms are photophobia along with glare sensitivity and blepharospasm. In addition, corneal crystal accumulation can cause other complications, such as recurrent corneal erosions, punctate or filamentary keratopathy, and chronic dry eye. Eventually, peripheral corneal neovascularization and limbal stem cell deficiency may develop. Ophthalmologists play a key role in the early diagnosis of patients with cystinosis. This review aims to not only raise awareness of secondary complications of corneal crystal accumulation, but also to highlight current treatment options and challenges that ophthalmologists and pediatricians might face.