Oculocutaneous tyrosinaemia or tyrosinaemia type 2: a case report

Abstract

Oculo-cutaneous tyrosinaemia type II is an autosomal recessive disease due to an abnormality of tyrosine metabolism, probably because of a deficiency of cytoplasmic tyrosine aminotransferase. It presents as a varying association of focal palmoplantar keratosis, bilateral keratitis and mental retardation. Herein, we report an 8-year-old boy with palmoplantar hyperkeratosis with peripheral oozing and dendritic keratitis appearing after the skin lesions. There was no mental deterioration despite the long delay in diagnosis of the disorder. The diagnosis was confirmed by the presence of hypertyrosinaemia and the absence of hepatorenal lesion. The child exhibited a remarkable degree of improvement in the hyperkeratotic lesions and keratitis after the dietary modifications were instituted. In conclusion, chronic focal bullous palmoplantar hyperkeratosis along with keratitis should alert the clinician to screen for abnormal serum and/or urine tyrosine level. Awareness of the presenting signs and symptoms may speed up the diagnosis and initiation of a tyrosine and phenylalanine-restricted diet that is most efficient in improving the symptoms and preventing visual and cognitive impairment.