SLC2A9--a fructose transporter identified as a novel uric acid transporter

SLC2A9 was recently cloned and identified as a member of the SLC2A gene family of hexose facilitative transporters, where its main physiological role was assumed to be in the transport of glucose and fructose. However, new findings have unearthed a novel role for SLC2A9 (also known as GLUT9) as a modulator of uric acid levels. Specifically, after conducting genome-wide scans, Doring et al. and Vitart et al. have identified several noncoding genetic variants of SLC2A9 that were strongly associated with a decrease in serum uric acid concentrations and an increase in fractional excretion of uric acid. Accordingly, the variants were also associated with a decreased risk of gout, suggesting a protective role for the minor alleles. Interestingly, in both of the studies, gender-specific effects were more pronounced in women than in men. Doring et al. estimated the additive effect to be -0.45 mg/ dl per copy of the minor allele in women and -0.25 mg/ dl in men. Overall, genetic variants of SLC2A9 are potentially responsible for 1.2-6.0% of the variance in serum uric acid concentrations. Of importance is the functional determination that SLC2A9 is a strong urate transporter, implicating it as a key player in the renal excretion of uric acid that could greatly impact clinical practices.