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.
Department of Pediatrics, Division of Endocrinology, University of California San Francisco, San Francisco, CA 94143, USA.
Ivy R
IR
Aslan
Guilherme M
GM
Campos
Melissa A
MA
Calton
Daniel S
DS
Evans
Raphael B
RB
Merriman
Christian
C
Vaisse
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