Fig. 2.

Urinary metadrenaline concentrations in patients with alkaptonuria before treatment with nitisinone and after no treatment (n = 7); treatment with 1 mg nitisinone daily (n = 7); treatment with 2 mg nitisinone daily (n = 8); treatment with 4 mg nitisinone daily (n = 8) and treatment with 8 mg nitisinone daily (n = 6). (a) 3-Methoxytyramine, (b) metadrenaline and (c) normetadrenaline. Dashed line = indicates upper limit of normal urine reference range for 3-methoxytyramine <1.4 μmol/24 h; metadrenaline <1.3 μmol/24 h; normetadrenaline <3.0 μmol/24 h; − = 95% confidence notched outlier boxplot; + = outlier; circle = individual patient concentrations. Significance testing compared metadrenaline concentrations before and after a 4-week trial of nitisinone. * = p ≤ 0.01; ** = p ≤ 0.03