Scientists at The Children’s Hospital of Philadelphia have identified both common and rare gene variants associated with the eating disorder anorexia nervosa.
In the largest genetic study of this psychiatric disorder, the researchers found intriguing clues to genes they are subjecting to further investigation, including genes active in neuronal signaling and in shaping interconnections among brain cells.
Anorexia nervosa (AN) affects an estimated 9 in 1000 women in the United States.
Patients have food refusal, weight loss, an irrational fear of weight gain even when emaciated, and distorted self-image of body weight and shape.
Women are affected 10 times more frequently than men, with the disorder nearly always beginning during adolescence.
AN has the highest mortality rate of all psychiatric disorders, and successful treatment is challenging.
Twin studies and other family studies have suggested that AN is strongly heritable.
“However, 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.
This is the first genome-wide association study on a large anorexia cohort, as well as the first study of copy number variations in the disorder.”
Hakon Hakonarson, M.D., Ph.D., director of the Center for Applied Genomics at The Children’s Hospital of Philadelphia.
The research appeared online in Molecular Psychiatry on Nov. 16.
Genome-wide association studies (GWAS) search for single-nucleotide polymorphisms, or SNPs—common gene variants that typically act as pointers to a gene region with a small effect on raising disease risk.
The study team also performed a parallel search for copy number variations (CNVs), rarer variants that usually have a stronger impact on disease risk.
The current anorexia study also investigated CNVs—deletions or duplications of DNA sequences. Previous research by Hakonarson and others has shown that CNVs play a significant role in other neuropsychiatric disorders, such as schizophrenia, bipolar disorder and autism.
The current study suggests that CNVs may play a less important role in anorexia than they do in schizophrenia and autism. Nonetheless, the researchers identified several rare CNVs that occurred only in AN cases, including a deletion of DNA on a region of chromosome 13.
Source: Children’s Hospital of Philadelphia
K. Wang et al, “A Genome-wide Association Study on Common SNPs and Rare CNVs in Anorexia Nervosa” Molecular Psychiatry, published online Nov. 16, 2010.
Tracy Lynn Cook is a writer in Gilbert, Arizona. To read more, please visit her blog at www.TLCsThoughts.com, or browse by topic:
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