A 2-year-old girl with no history of eye problems presented for further evaluation. The parents reported early progress and normal gross motor development followed at 9 months of age by failure to thrive, including abnormally low weight gain and height. The child had been experiencing slight photophobia and polyuria at home 2 months before the evaluation. On examination, the patient provided complete cooperation. Good fixation, following, and interest in toys was demonstrated with each eye. Binocular fixation was found, and no nystagmus was present. Eye movements were full, and eyelids and conjunctiva were normal (Figure 1A). The corneas were carefully inspected by hand slit-lamp examination, and uncertain irregularity of the epithelium was noted. A formal slit-lamp examination (16×) was performed, and a diffuse, fine diagnostic crystal formation was observed throughout the peripheral corneal epithelium and anterior corneal stroma of both eyes (Figure 1B). On further examination, the anterior chambers were clear, the pupils reacted well to light, the lenses were clear, and no abnormalities were observed within the fundi. Cycloplegic refraction found low hyperopia in each eye. Analysis of the white cells found increased levels of an amino acid, supporting the clinical impression. A topical medication was recommended. This patient's younger sibling was examined at 3, 5, and 7 months of age and crystals were not found. When observed again at 9 months of age, the sibling demonstrated very fine crystal deposition superotemporally in both corneas.
What's Your Diagnosis?
For the correct answer, see page 89.
The answer for What's Your Diagnosis? is nephropathic cystinosis.
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