Double Gene Variants Linked to Higher Body Mass
Variants found in morbidly obese patients
MONDAY, March 17 (HealthDay News) -- Variants of two obesity-associated genes, when both present, are associated with higher body mass index (BMI) in morbidly obese patients undergoing bariatric surgery, researchers report in the March issue of the Archives of Surgery.
Xin Chu, Ph.D., and colleagues from the Geisinger Clinic in Danville, Pa., retrospectively analyzed single nucleotide polymorphisms in the fat mass and obesity associated gene (FTO) and insulin induced gene 2 (INSIG2) in 707 adult patients undergoing gastric bypass surgery. Patients had a BMI of at least 40.
The researchers found that about 21 percent of patients were homozygous for the FTO variant, 13 percent were homozygous for the INSIG2 variant, and 3.4 percent were homozygous for both. Although mean BMIs for patients homozygous for each gene were similar to non-homozygotes, BMIs were significantly higher for FTO/INSIG2 double homozygotes and homozygote/heterozygote pairs, the report indicates.
"This study represents a good start in trying to characterize the full complement of obesity genes," Edward H. Livingston, M.D., from the University of Texas Southwestern School of Medicine in Dallas, writes in an accompanying editorial. "Correlation of genetic alterations with the heterogeneity of patients' responses to surgery is bound to unlock some of the genetic mysteries that underlie obesity."