Anorexia Linked to Uncommon Genes in First Study
In a first study, researchers have found a link between the mental disorder anorexia nervosa (AN) and uncommon genes. The findings lead scientists to continue searching for rare genes that play a role in the psychiatric eating disorder that affect 9 in 1000 women.
Genes Identified that Occur only in Anorexia
Scientists at The Children’s Hospital of Philadelphia say they have identified genes that occur only in anorexia that play a role in how neurons connect and signal the brain. Treatment of anorexia is challenging, and causes more deaths than any other mental health disorder, making it important to understand the complexities of who is susceptible.
Hakon Hakonarson, M.D., Ph.D., director of the Center for Applied Genomics at The Children’s Hospital of Philadelphia explains twin studies have suggested anorexia is hereditary, but “despite various genetic studies that identified a handful of candidate genes associated with AN, the genetic architecture underlying susceptibility to AN has been largely unknown.”
The study is the first to seek out rare genes that have a larger impact on developing anorexia than single-nucleotide polymorphisms, or SNPs that only point to regions of gene variations but have little effect on increasing the chances of AN.
“We confirmed results of previous studies of anorexia nervosa: SNPs in the gene OPRD1 and near the gene HTR1D confer risk for the disease,” said Hakonarson. “We did not detect other obvious candidate genes, but we did generate a list of other genes that we are analyzing in follow-up studies.”
The researchers found a link between anorexia and cadherin genes that influence how cells communicate with each other in the brain and are associated with autism spectrum disorders.
The researchers also looked at gene deletions and duplications known as CNVs that may play a less important role in AN than in schizophrenia, bipolar disease or autism. They did find some rare variations including a deletion of DNA on a region of chromosome 13 that only occurs in anorexia.
For the study researchers looked at DNA from 1,003 individuals with anorexia, 24 of whom were male with an average age of 27. The control group was from a pediatric group of 3733 subjects with an average age of 13 from the Children’s Hospital pediatric network.
“Our study suggests that both common SNPs and rare CNVs contribute to the pathogenesis of anorexia nervosa,” said Hakonarson. “The gene variants we discovered are worthy of further analysis in independent cohorts. However, the relatively modest number of anorexia cases explained by these results we found suggests that many other candidate genes remain unknown. Future studies will require much larger sample sizes to detect additional gene variants involved in this complex disorder.”
Unraveling the mystery of anorexia, a mental health disorder associated with distorted body image, refusal to eat, emaciation and fear of weight gain will take time. The new study shows there are common and uncommon genes worthy of exploring that play a role in susceptibility to the eating disorder.