A child with dendritiform eye lesions and developmental delay.

Purpose: Tyrosinemia Type II (Richner-Hanhart syndrome) is a rare autosomal recessive disease that occurs due to deficiency in the enzyme tyrosine aminotransferase and can result in an ulcerated keratitis. We present a case of a young patient with oculocutaneous tyrosinemia despite a negative newborn screen. Observations: A 15 month old boy with an uncomplicated birth history and negative newborn screen presented with a unilateral central irregular epithelial defect and hyperkeratotic lesions on his fingertips and soles. A month later, the patient developed bilateral dendritiform epithelial erosions. Following a series of antiviral, antibiotic, and lubricating treatments, there was a waxing and waning course of epithelial healing. After the patient was lost to follow up for one year, the patient presented with a new global developmental delay prompting further workup. Tyrosine and phenylalanine levels were ordered which confirmed a diagnosis of Tyrosinemia Type II, and the patient was started on a low-protein diet. A month later, the patient's epithelial defects and ocular symptoms were resolved. Conclusion and Importance: Presentation of a dendritiform epithelial erosion, whether unilateral or bilateral, accompanied by symptoms of developmental delay and palmoplantar hyperkeratotic lesions should prompt measurement of tyrosine and phenylalanine levels. As dermatologic lesions and variable developmental delay may not appear until later in the course of disease, diagnosis may depend on early recognition of ocular signs and symptoms even with negative newborn screening. Prompt diagnosis and diet modification is necessary to prevent developmental delay in this disease. To our knowledge, this is the first Tyrosinemia Type II case in the literature manifesting as an asynchronous bilateral eye disease.