Gout is the most common inflammatory joint disease. High heritability of hyperuricemia—the main driver of urate crystal deposition and the development of gout—has led to efforts to identify susceptibility genes, explained a research team led by Chang-Fu Kuo, MD, of the University of Nottingham, Nottingham, U.K. Dr. Kuo and colleagues sought to examine familial clusters of gout and to estimate the heritability and environmental contributions to gout susceptibility in the general population in Taiwan. Taiwan has one of the highest reported estimates of gout prevalence worldwide.
Kuo’s group evaluated information from 1,045,059 patients with physician-diagnosed gout, obtained from a national health research data base in Taiwan. Among subjects with a first-degree relative with gout, the risk for developing gout themselves was approximately twice that seen in the general population. The risk increased with the number of first-degree relatives affected.
Men and women whose second-degree relatives suffered from gout had a 27% and 40% increased risk of gout compared with the general population.
Individuals with a twin affected by gout had an eightfold increased risk and those with an affected sibling had a 2.6 times increased risk. Individuals with an affected son or daughter and those with an affected parent had a twofold increased risk. Those with an affected grandchild had a 48% increased risk and individuals with an affected niece or nephew had a 40% increased risk.
Kuo and co-investigators also found evidence that environmental factors shared by families, such as diet and lifestyle, and genetic factors both predisposed to gout within families. Although environmental factors contributed a higher proportional risk, genetic factors still appeared to have a substantial role.
The researchers noted that because the study was confined to Taiwan, studies of familial risk in other populations are needed to determine the generalizability of the findings to other populations.