What does this mean?
This is exciting, but not unexpected news. Now with genome wide association studies in full force- we are witness to the explosion of discoveries of genetic factors contributing to a multitude of pathologies. Of course, this isn't the only answer. There are many cases of extreme obesity/thinness with unknown cause. Some will involve other genes yet to be discovered as well as the many epigenetic and environmental factors which influence and regulate phenotype.
Sure, there's promise of something big, but now comes the long, hard slog - figuring out how these genes interact with their environment to bring about such phenotypes.
There is much work ahead...