A patient with hereditary Tyrosinemia Type I who is treated with nitisinone may develop corneal deposits caused by the deposition of tyrosine crystals.


Patient selection: hereditary tyrosinemia type I treated with nitisinone (which blocks the tyrosine catabolic pathway)


The corneal deposits tend to appear when the blood tyrosine concentration is elevated (often > 600 micromol/L). This usually occurs when the patient does not restrict tyrosine intake. The deposits disappear when blood tyrosine levels are reduced.


Clinical features:

(1) photophobia

(2) itchiness or discomfort of the eyes

(3) bilateral, linear branching subepithelial corneal opacities


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