Exploring the Biochemical Markers for Vitiligous Patients: Tyrosinase and Amino Acids

Melanin is an organic biomolecule arranged in polymers that form the pigment of various organisms, melanocytes are group of cells responsible for the production of melanin through several biochemical reactions including the oxidation of tyrosine followed by polymerization processes which are collectively called melanogenesis. Eumelanin is formed from the oxidation of tyrosine by tyrosinase enzyme in unique organelles called melanosomes. Vitiligo is an autoimmune disease characterized by melanin skin loss with unknown cause.
This study aims to discover the relationship between biochemical parameters (tyrosinase enzyme, phenylalanine, cysteine and tyrosine) with melanin deficiency, which may be valuable in predicting the cause of pigment loss in vitiligous patients.
The study was performed in Al-Ramadi Teaching Hospital on 42 vitiligous patients and 42 healthy individuals. Serum tyrosinase enzyme was estimated for both patients and healthy individual groups by enzyme-linked immunosorbent assay (ELISA) technique, amino acids levels were determined by amino acid auto analyzer device. Results of our study showed a significant decrease in serum tyrosinase enzyme, phenylalanine and tyrosine for patients compared with healthy group in a statistical threshold of (p<0.0001), in contrast, no significant difference was seen in cysteine levels showed between patients and healthy individuals. The studied parameters showed the decreasing of the area under the receiver operating characteristic (AUROC) curve: tyrosinase (p<0.9516), phenylalanine (p <0.9125) and tyrosine (0.8127), new cut-off values were determined of tyrosinase (p <184.1), phenylalanine (p <367.5) and tyrosine (p <538.9). We conclude from the results of the current study that melanin pigment synthesis pathway may be affected by the decreased levels of tyrosinase, phenylalanine, and tyrosine .These parameters are valuable in the diagnosis and/or treatment of vitiligo. Additionally; they may considered in further biochemical studies.