Objective: To comprehensively describe the ophthalmic characteristics of patients with mucolipidosis type IV.
Design: Prospective natural history study.
Participants: Twenty-two patients with confirmed mucolipidosis type IV. METHODS OR TESTING: External and slit-lamp examination with dilated funduscopy, photography of corneal and retinal lesions, and exfoliative conjunctival cytology were performed.
Main outcome measures: Grading of corneal, optic nerve, retinal vasculature, and pigmentary abnormalities.
Results: All patients exhibited some degree of corneal epithelial haze, optic nerve pallor, retinal vascular attenuation, and retinal pigment epithelial changes. The associated ocular findings observed in decreasing order of frequency were strabismus, corneal erosion, cataract, corneal abnormalities, fundus abnormalities, and ptosis. The older patients were significantly more likely to demonstrate severe optic nerve pallor, retinal vascular attenuation, and corneal epithelial haze. Conjunctival cytologic studies showed characteristic lysosomal inclusions on light and electron microscopy.
Conclusions: Patients with mucolipidosis type IV have characteristic ophthalmic features, most of which have a progressive course. Conjunctival cytologic studies help confirm the diagnosis of this disorder.