Lack of association of ankylosing spondylitis with the most common NOD2 susceptibility alleles to Crohn's disease.

To investigate whether the 3 most common mutations in the NOD2 gene that confer susceptibility to Crohn's disease (CD) are also associated with ankylosing spondylitis (AS). DNA from 112 patients with AS and 168 controls of homogenous Spanish ancestry were studied. The frequencies of the pathogenic alleles of NOD2 (3020insC, 2722G>C, and 2104C>T) were determined by analysis of the melting curves after hybridization with FRET probes on a Light Cycler real-time polymerase chain reaction (PCR) system. Results. NOD2 allelic frequencies in controls (3020insC, 0.009; 2722G>C, 0.009; 2104C>T, 0.042) did not significantly differ from patients with AS (3020insC, 0.009; 2722G>C, 0.004; 2104C>T, 0.031). The 3 most common CD NOD2 mutations do not contribute to disease susceptibility to AS, and therefore do not explain the susceptibility locus for AS in chromosome 16q.