Once considered the wages of gluttony, new research suggests that gout may have as much to do with genetics as indulgence.
Gout occurs when high levels of uric acid in the bloodstream cause the substance to form crystals in the joints, leading to painful inflammation and the growth of nodules known as tophi. Anything that increases the production of uric acid or interferes with the body’s ability to dispose of it through the kidneys – including the consumption of protein-rich foods and alcohol – can aggravate the condition.
Anything that increases the production of uric acid or interferes with the body’s ability to dispose of it through the kidneys – including the consumption of protein-rich foods and alcohol – can aggravate the condition.
But researchers have learned recently that variations in a gene involved in the excretion of uric acid by the kidneys can also increase a person’s chances of developing gout. And now a study published this week in the medical journal The Lancet confirms that discovery and also associates two additional genes with the disease.
The study measured uric acid levels in nearly 12,000 people of European ancestry from the Netherlands and the United States. It identified three different single-letter genetic variations, known as SNPs, that were associated with differences in uric acid concentration.
Those SNPs also turned out to be associated with the chances that a person had gout.
And when the researchers tested their observation in a third U.S. population of nearly 14,000 whites and African Americans, they found that one of the three SNPs was also associated with gout among blacks.
All three SNPs were located in genes that are active in the kidneys and thought to be involved in uric acid excretion.
Though each of the three SNPs individually affected a person’s chance of having gout by less than a factor of two, the researchers point out that in one of their study populations the combination of all three had a 40-fold effect on a person’s risk for the disease.
That’s substantially higher than the effects of diet, obesity and other risk factors for gout, which affects less than one percent of the US population.