Polymorphism in the interleukin-1 receptor antagonist gene is associated with alcoholism in Spanish men.
BACKGROUND: A polymorphism located in intron 2 of the interleukin-1 receptor antagonist (IL1RN) gene recently has been associated with the development of hepatic fibrosis in Japanese alcoholics. In the present study, we analyzed whether there is an association between this polymorphism, alcoholism, and alcoholic liver disease in a Spanish male population of alcoholics. METHODS: The IL1RN genotype was assessed by polymerase chain reaction by using oligonucleotides that flank a variable nucleotide tandem repeat polymorphism located in intron 2 of this gene in 90 male alcoholic patients from Spain: 30 alcohol-dependent men, 30 alcohol abusers, and 30 alcoholics with liver cirrhosis. We also studied 40 healthy subjects. RESULTS: The distribution of the IL1RN allelic frequencies in Spanish healthy subjects is similar to that previously reported in White subjects. However, the A1 allele is overrepresented in Spanish alcoholics when compared with healthy subjects. No significant differences in allelic frequencies were observed between alcoholics with liver cirrhosis and alcoholics without liver disease or between alcohol-dependent subjects and alcohol abusers. CONCLUSION: The presence of the A1 allele of the IL1RN gene is associated with a higher risk of alcoholism in Spanish men.