Missing Gene Linked to Extreme Obesity

On February 6, 2010, in Uncategorized, by Andrea

More news from Medscape:

Missing Genes Linked to Extreme Obesity

Jennifer Warner

February 4, 2010 — Missing genes may be behind at least some cases of morbid or extreme obesity, according to a new study.

Researchers found that a small but significant portion of morbidly obese people are missing a section of their DNA that may contribute to their obesity.

The results suggest around seven in every 1,000 morbidly obese people are missing this section of their DNA, which contains about 30 genes. This genetic variation was not found in any people of normal weight.

“Although the recent rise in obesity in the developed world is down to an unhealthy environment, with an abundance of unhealthy food and many people taking very little exercise, the difference in the way people respond to this environment is often genetic,” says researcher Philippe Froguel, of the School of Public Health at Imperial College London, in a news release.

Overall, researchers say about one in 20 cases of morbidly obese people is caused by genetics, including previously identified genetic mutations and these missing genes. But many more genetic mutations linked to obesity are yet to be found.

The researchers hope that identifying genetic variations that cause people to be morbidly obese will lead to the development of genetic tests that can help determine the best treatment.

“If we can identify these individuals through genetic testing, we can then offer them appropriate support and medical interventions, such as the option of weight loss surgery, to improve their long-term health,” says Froguel.

In the study, published in Nature, researchers first identified the missing genes in teenagers and adults who had learning difficulties or delayed development.

The results showed 31 people had nearly identical deletions in one copy of their DNA. All of the adults with this genetic variation had a BMI of over 30, which means they were obese.

People inherit two copies of their DNA, one copy from their mother and one from their father. Sometimes one copy of one or more genes is missing and can affect a person’s development, as shown by this study.

In the second part of the study, researchers examined the genomes or genetic maps of 16,053 European people who were either obese or normal weight. They found 19 more people with the same set of missing genes. All of these individuals were morbidly obese.

The study showed people with the genetic deletion tended to be normal-weight toddlers who became overweight during childhood and morbidly obese as adults.

Researchers did not find the genetic deletion in any normal-weight people. Although they do not know the function of the missing genes, previous studies suggest some of them may be involved with delayed development, autism, and schizophrenia.

SOURCES:

Walters, R. Nature, Feb. 3, 2010, online advance edition.

News release, Imperial College London.

DS for superobesity?

On January 11, 2010, in Uncategorized, by Andrea

The date says Jan 08, but with some digging, I REALLY think it’s a typo and meant to say Jan 2010.

Regardless, this is something the DS folks have been saying for quite some time now..

From Medscape:

Duodenal Switch Is Superior to Gastric Bypass for Superobesity

NEW YORK (Reuters Health) Jan 08 – “Super-obese” patients – those with a body mass index (BMI) of more than 50 kg/m2 – lose significantly more weight after laparoscopic duodenal switch (LDS) than after laparoscopic Roux-en-Y gastric bypass, a randomized trial has shown.

At one year after surgery, mean BMI was 32.5 kg/m2 in the 29 patients who had been randomized to undergo LDS and 38.5 kg/m2 in the 31 who had gastric bypass, the investigators report in the December 24th online issue of the British Journal of Surgery.

At that point, on average, the gastric bypass patients had lost 54.4% of their excess BMI whereas the LDS patients had lost 74.8%. All had BMIs ranging from 50 to 60 kg/m2 at baseline.

Perioperative safety was comparable in both groups.

Lead author Dr. T. T. Sovik of Oslo University Hospital Aker in Oslo, Norway, and colleagues note that gastric bypass has had high failure rates in patients with BMIs between 50 and 60 kg/ m2.

The “technically more complex” LDS procedure involves biliopancreatic diversion with creation of a duodenal-ileo anastomosis.

Five surgeons at two hospitals performed all the surgeries. The surgeon at each hospital who had the most experience with LDS performed all the LDS cases. Mean operating times were 91 minutes for bypass and 206 minutes for LDS. One LDS case was converted to open surgery.

Seven LDS patients had 11 early complications, and four bypass patients had 10 early complications (p = ns). Three patients went back to the operating room in the first few days after surgery, including two who had gastric bypass (and developed anastomotic leaks) and one who had LDS (and had a leak from the duodenal stump).

No patients died. The median length of hospital stay was two days after bypass and four days after LDS (P < 0.001).

Late problems developed in four bypass patients (five complications) and nine LDS patients (12 complications) (p = ns). Three LDS patients had late reoperations (for inflammation in the transverse mesocolon, ascites, or common bile duct stones).

The surgeons who did the LDS cases had each done fewer than 20 procedures at the study’s outset, the researchers note, “and a reduction in operating time and morbidity rate might be expected with increased experience.”

The only two patients with metabolic disturbances were in the LDS group, the researchers add, “and although this is a small number at one year, a difference in clinically important metabolic complications between the two procedures may be revealed with extended follow-up.”

“The large difference in BMI at 1 year between gastric bypass and LDS in the present study (6 kg/m2), and the stability of the weight loss after duodenal switch shown by others, suggest that LDS is better at promoting short- and long-term weight loss in super-obese patients,” the researchers conclude.

Br J Surg 2009.