Cannabinoid-1 receptor agonists: a therapeutic option in severe, chronic anorexia nervosa?

A next generation sequencing gene panel for use in the diagnosis of anorexia nervosa

PURPOSE

The aim of this study was to increase knowledge of genes associated with anorexia nervosa (AN) and their diagnostic offer, using a next generation sequencing (NGS) panel for the identification of genetic variants. The rationale underlying this test is that we first analyze the genes associated with syndromic forms of AN, then genes that were found to carry rare variants in AN patients who had undergone segregation analysis, and finally candidate genes intervening in the same molecular pathways or identified by GWAS or in mouse models.

METHODS

We developed an NGS gene panel and used it to screen 68 Italian AN patients (63 females, 5 males). The panel included 162 genes. Family segregation study was conducted on available relatives of probands who reported significant genetic variants.

RESULTS

In our analysis, we found potentially deleterious variants in 2 genes (PDE11A and SLC25A13) associated with syndromic forms of anorexia and predicted deleterious variants in the following 12 genes: CD36, CACNA1C, DRD4, EPHX2, ESR1, GRIN2A, GRIN3B, LRP2, NPY4R, PTGS2, PTPN22 and SGPP2. Furthermore, by Sanger sequencing of the promoter region of NNAT, we confirmed the involvement of this gene in the pathogenesis of AN. Family segregation studies further strengthened the possible causative role of CACNA1C, DRD4, GRIN2A, PTGS2, SGPP2, SLC25A13 and NNAT genes in AN etiology.

CONCLUSION

The major finding of our study is the confirmation of the involvement of the NNAT gene in the pathogenesis of AN; furthermore, this study suggests that NGS-based testing can play an important role in the diagnostic evaluation of AN, excluding syndromic forms and increasing knowledge of the genetic etiology of AN.

LEVEL OF EVIDENCE

Level I, experimental study.

Genetic contributions to the etiology of anorexia nervosa: New perspectives in molecular diagnosis and treatment

Background

Anorexia nervosa is a multifactorial eating disorder that manifests with self‐starvation, extreme anxiety, hyperactivity, and amenorrhea. Long‐term effects include organ failure, disability, and in extreme cases, even death.

Methods

Through a literature search, here we summarize what is known about the molecular etiology of anorexia nervosa and propose genetic testing for this condition.

Results

Anorexia nervosa often has a familial background and shows strong heritability. Various genetic studies along with genome‐wide association studies have identified several genetic loci involved in molecular pathways that might lead to anorexia.

Conclusion

Anorexia nervosa is an eating disorder with a strong genetic component that contributes to its etiology. Various genetic approaches might help in the molecular diagnosis of this disease and in devising novel therapeutic options.

Anorexia nervosa is a multifactorial eating disorder with a strong genetic component that manifests with self‐starvation, extreme anxiety, hyperactivity, and amenorrhea. Through a literature search, here we summarize what is known about the molecular etiology of anorexia nervosa and propose genetic testing for this condition.

Dronabinol in severe, enduring anorexia nervosa: a randomized controlled trial

OBJECTIVE

The evidence for pharmacological treatment of severe, longstanding anorexia nervosa (AN) is sparse and the few controlled pharmacologic studies have focused on a narrow range of drugs. The aim of the present study was to investigate the effects of treatment with a synthetic cannabinoid agonist on body weight and eating disorder-related psychopathological personality traits in women with severe, enduring AN.

METHOD

This add-on, prospective, randomized, double blind, controlled crossover study was conducted between 2008 and 2011 at a specialized care center for eating disorders. Twenty-five women over 18 years with AN of at least 5 years duration were randomized to treatment with either dronabinol-placebo or placebo-dronabinol. In addition to the standardized baseline therapeutic regime, the participants received dronabinol, 2.5 mg twice daily for 4 weeks and matching placebo for 4 weeks, separated by a 4-week wash-out period. Primary outcome was the mean change in body weight. Secondary outcome was score changes on the Eating Disorder Inventory-2 (EDI-2). Data were analyzed for the 24 patients who completed the trial.

RESULTS

During dronabinol treatment, participants gained 0.73 kg (t = 2.86, df = 22, p < 0.01) above placebo without significant psychotropic adverse events. Dronabinol significantly predicted weight gain in a multiple linear regression including EDI-2 body dissatisfaction score and leptin. EDI-2 subscale scores showed no significant changes over time.

DISCUSSION

Dronabinol therapy was well tolerated. During four weeks of exposure it induced a small but significant weight gain in the absence of severe adverse events.