Different mutations in fumarylacetoacetatase (FAH) gene can lead to tyrosinemia type1 (HT1), relatively rare autosomal disorders. Nearly 50 mutations in FAH gene have been identified in different races around the world. Here we presented a boy aged 2 years and 9 months old was diagnosed with HT1 compound with dextrocardia based on his biochemical abnormality and cardio logical examinations. Screening of FAH gene exposed a heterozygous nonsense mutation R237X that was not already reported in Iranian patients. This mutation revealed a chronic progression of disease in this child.