Genetic Obesity and Bariatric Surgery Outcome in 1014 Patients with Morbid Obesity.

BACKGROUND: Mutations in the leptin-melanocortin pathway genes are known to cause monogenic obesity. The prevalence of these gene mutations and their effect on weight loss response after bariatric surgery are still largely unknown. OBJECTIVE: To determine the prevalence of genetic obesity in a large bariatric cohort and evaluate their response to bariatric surgery. METHODS: Mutation analysis of 52 obesity-associated genes. Patient inclusion criteria were a BMI > 50 kg/m2, an indication for revisional surgery or an early onset of obesity (< 10 years of age). RESULTS: A total of 1014 patients were included, of whom 30 (3%) were diagnosed with genetic obesity, caused by pathogenic heterozygous mutations in either MC4R, POMC, PCSK1, SIM1, or PTEN. The percentage total body weight loss (%TBWL) after Roux-en-Y gastric bypass (RYGB) surgery was not significantly different for patients with a mutation in MC4R, POMC, and PCSK1 compared with patients lacking a molecular diagnosis. Of the confirmed genetic obesity cases, only patients with MC4R mutations receiving a sleeve gastrectomy (SG) showed significantly lower %TBWL compared with patients lacking a molecular diagnosis, during 2 years of follow-up. CONCLUSIONS: In this cohort of morbid obese bariatric patients, an estimated prevalence of monogenic obesity of 3% is reported. Among these patients, the clinical effects of heterozygous mutations in POMC and PCSK1 do not interfere with the effectiveness of most commonly performed bariatric procedures within the first 2 years of follow-up. Patients with MC4R mutations achieved superior weight loss after primary RYGB compared with SG.

[Genetic obesity: new diagnostic options]. / Genetische obesitas.

- Obesity is an important risk factor for morbidity and premature death, as well as a contributing factor to psychosocial problems. The incidence of obesity has increased dramatically over the last few decades.- Obesity is considered to be a multifactorial condition in which both environmental factors and genetic factors play a part.- In approximately 5% of patients with morbid obesity, a monogenic cause can be identified. Mutations in the MC4R gene are the most frequently occurring monogenic cause of obesity.- The department of Genetics at the VU University Medical Center Amsterdam offers morbidly obese patients a diagnostic analysis of 50 obesity-associated genes. - An underlying obesity-associated genetic defect can influence patient response to certain treatments. Therefore, if the gene defect is known, it can be taken into account when considering treatment options.- The understanding of the genetics of obesity will significantly contribute to research into the development of personalized treatment options.