Oculocutaneous tyrosinemia in a Colombian patient: case report and literature review

Background: Tyrosinemia type II (OMIM 276600) or oculocutaneous tyrosinemia
is an extremely rare disorder secondary to a deficiency of the cytoplasmic enzyme, tyrosine aminotransferase (TAT), leading to tyrosine accumulation. TAT gene contains 12 exons, which code an active protein containing 454 amino acids. The main manifestations of this enzyme deficiency are corneal thickening, palmar and plantar hyperkeratosis, as well as intellectual disability. Liver and kidney functions are generally normal. We described a Colombian patient diagnosed at an adult age.
Case Report: A 33- year-old male from consanguineous parents was referred to genetics by suspicion of Papillon-Lefevre syndrome due to hyperkeratosis of the palms and soles and early periodontitis; Additionally, he has a mental disability and a history of recurrent keratitis in infancy, which resolved. A molecular panel of hyperkeratosis was performed, and a homozygous pathogenic variant in gene TAT c.341G>C (p.Gly114Ala) was found; plasma tyrosine levels were markedly elevated (1039 umol/L, reference value 39-86). A clinical diagnosis of tyrosinemia type II was confirmed. A dietary restriction of phenylalanine and tyrosine, oral and topical retinoids were started to improve skin lesions.
Discussion: This case shows the need for clinicians and healthcare providers to be informed about metabolic diseases in adulthood and the importance of diagnosing tyrosinemia type II in individuals with palmoplantar hyperkeratosis. These patients can be managed with dietary protein restriction, presenting improvement in symptoms and quality of life.
Conclusion: We present the first reported case of Tyrosinemia type II in Colombia. Our case highlights the wide spectrum of Tyrosinemia type II and the importance of considering this diagnosis in individuals with skin and ocular manifestations.