Fig. 2

c.269G > A/p.R90H mutation identified in the RHUC patient. a This mutation is located close to the second transmembrane region (TM2) as indicated by the black arrow. b This identified amino acid substitution displays high evolutionary conservation among different species as indicated by the black arrow. c 3-D structures of the wild-type and c.269G > A/p.R90H URAT1 proteins with prediction software. The left shows the structure of the wild type. The right shows the structure of p.R90H. The hydrogen bond between His90 and Gln93 in the mutant is weakly formed (bond length is 3.1 Å) in comparison with the wild type (bond length is 2.3 Å)