Weight loss after Roux-en-Y gastric bypass in obese patients heterozygous for MC4R mutations.
BACKGROUND
Heterozygous mutations in melanocortin-4 receptor (MC4R) are the most frequent genetic cause of obesity. Bariatric surgery is a successful treatment for severe obesity. The mechanisms of weight loss after bariatric surgery are not well understood.


METHODS
Ninety-two patients who had Roux-en-Y gastric bypass (RYGB) surgery were screened for MC4R mutations. We compared percent excess weight loss (%EWL) in the four MC4R mutation carriers with that of two control groups: 8 matched controls and with the remaining 80 patients who underwent RYGB.


RESULTS
Four patients were heterozygous for functionally significant MC4R mutations. In patients with MC4R mutations, the %EWL after RYGB (66% EWL) was not significantly different compared to matched controls (70% EWL) and non-matched controls (60% EWL) after 1 year of follow-up.


CONCLUSIONS
This study suggests that patients with heterozygous MC4R mutations also benefit from RYGB and that weight loss may be independent of the presence of such mutations.
Aslan
Ivy R
IR
Department of Pediatrics, Division of Endocrinology, University of California San Francisco, San Francisco, CA 94143, USA.
Campos
Guilherme M
GM
Calton
Melissa A
MA
Evans
Daniel S
DS
Merriman
Raphael B
RB
Vaisse
Christian
C
D000328:Adult; D016022:Case-Control Studies; D005260:Female; D015390:Gastric Bypass; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009765:Obesity / Q000235:genetics* / Q000601:surgery; D044105:Receptor, Melanocortin, Type 4 / Q000235:genetics*; D015431:Weight Loss / Q000235:genetics*
C470072:MC4R protein, human; D044105:Receptor, Melanocortin, Type 4