Individuals homozygous for genotype iNOS22*A/A tended to be more frequent in achalasia (20%vs 11%, odds ratio [OR] 1.79, 95% confidence interval [CI] 0.89-3.59, p= 0.09) as were those homozygous for the rare eNOS*4a allele (6.2%vs 1.4%, OR 4.5, 95% CI 0.89-22.67, p= 0.1) although the difference did not reach statistical significance.