The authors used a process called candidate gene association analysis to identify two genes from a region on the short arm chromosome 1, previously identified as likely to contain genes contributing to anorexia nervosa, that may contribute to the risk of developing anorexia nervosa. When the authors compared anorexia patients to control individuals, they found statistically significant association of sequence polymorphisms at these two genes to anorexia nervosa, with increasing risk to individuals carrying specific alleles for developing anorexia nervosa.
To perform the gene association analysis, the researchers focused on a region of the short arm of chromosome 1. Earlier studies by the same researchers found this region was likely to contain genes contributing to anorexia nervosa in families. The researchers used candidate gene analysis to investigate several genes in the chromosome 1 region, using both positional information and biological information about genes in this region to nominate three genes for detailed analysis. In the candidate gene association analysis, the researchers analyzed sequence polymorphisms in DNA samples from families with anorexia and other eating disorders and from individuals not affected with anorexia nervosa. Two genes in the chromosome 1 region, HTR1D, the gene that codes for the serotonin 1D receptor, and OPRD1, the gene that codes for the delta opioid receptor, demonstrated statistically significant association to anorexia nervosa.