Evidence of complex involvement of serotonergic genes with restrictive and binge purge subtypes of anorexia nervosa.

OBJECTIVES: There is mixed evidence of association of serotoninergic genes with anorexia nervosa (AN), but substantial evidence for the involvement of serotonergic mechanisms in appetite control. This study was designed to investigate possible associations between the two subtypes of AN (Restricting-RAN, and Binge-purging-BPAN) and polymorphisms within five genes encoding for proteins involved in the serotoninergic system. METHODS: In order to carry out this investigation we have conducted a case-control association study on 226 females meeting the criteria for AN, and 678 matched healthy females. RESULTS: Our data show a significant association between polymorphisms with the gene encoding HTR2A with both AN subtypes, an association between polymorphisms within the genes encoding HTR1D and HTR1B with RAN, and an association between polymorphisms within the gene encoding HTR2C with BPAN. No associations were found for any polymorphisms of the serotonin transporter gene. This outcome indicates a substantial and complex inter-relationship between serotoninergic genes and AN. CONCLUSIONS: Given these data we hypothesis that the expression or control of expression of several genes of the serotoninergic system, and interactions between these genes, could exert considerable influence over the specific symptomatology of the subtypes of AN.

Further evidence of association of OPRD1 & HTR1D polymorphisms with susceptibility to anorexia nervosa.

BACKGROUND: A recent study reported strong evidence for the involvement of a region on human chromosome 1 and genetic susceptibility to anorexia nervosa (AN). A more detailed analysis of this region has suggested 2 genes that may account for this susceptibility. These data suggest that polymorphisms in both the serotonin 1D (HTR1D) and opioid delta 1 (OPRD1) receptor genes show a significant association with restricting AN (RAN). METHODS: In the current study, we have conducted an independent association study on 226 females meeting DSM-IV criteria for AN and 678 matched volunteers. RESULTS: We genotyped 4 SNPs in HTR1D and 6 SNPs in OPRD1. 3 SNPs were found to be associated with both RAN and binge-purge AN (BPAN) within the gene for OPRD1. We also found evidence of association between 2 polymorphisms within HTR1D and RAN. CONCLUSIONS: These data support the hypothesis that polymorphisms within this region form a component of the genetic basis to susceptibility to RAN. However, further work is required to understand the processes that may be mediated by these genes.