Homozygous frameshift mutation in the SLC22A12 gene in a patient with primary gout and high levels of serum uric acid

Abstract
Idiopathic renal hypouricaemia (IRH) is an autosomal recessive disorder characterised by increased uric acid excretion.1 The main biochemical defect is abnormal uric acid transport at the proximal tubule. URAT protein seems to be the major mechanism regulating blood urate levels.2,3 Most patients with IRH (Online Mendelian Inheritance in Man 607 096) harbour homozygous deleterious mutations in the SLC22A12 gene, which encodes for URAT1 protein.2 The major clinical manifestation of IRH is the presence of uric acid stones in the urinary tract.4 Around 50% of patients with IRH are Japanese.