Comparison of phenylalanine and tyrosine in urine of patients with vitiligo and normal subjects

Amino acids are one of the most necessary substances in intracellular metabolic processes.aromatic aminoacids such as phenylalanine and tyrosine are precursor of melanin so are important materials for the skin pigmentation.metabolic disorders in the melanin synthesis causes milky macules on the skin of patients,known as vitiligo.these patients are hypersensitive to sunlight and consequently at a higher risk for skin malignancies.because of negative psychological effects most patients (especially women)try to hide their disease.moreover long term treatment causes patients hoprlessness.in this study carried out on 50 vitiligo patients and 50 control cases,matched for sex and age the amount of phenylalanine and tyrosine in the fasting urine  were determined by thin layer chromatography (TLC) method.results showed a significant difference (p<0.05) between the amount of phenylalanine in the urine of case group(8.15+_3.72 mg/dl) and control group (6.35+_3.94mg/dl).the amount of tyrosine in the urine of case group (9.56+_50.5 mg/dl) was less than that in the control group (11.32+_6.17mg/dl) and comparison of two groups in this regard showed a significant differnce only in the male subjects(p<0.01).ratio of phenylalanine and tyrosine to creatinine in urine  was not significantly different in he two groups.