Genes and obesity

Thick or thin. Whichever you are, it may not be your fault.

HealthFirst reporter Leslie Toldo says our weight may boil down to a genetic link we share with mice.

Over half of us humans are overweight. That's not really new, but for some, that extra fat may have more to do with destiny than lifestyle.

Lisa Bohner has one wish. "To have life again. To be normal."

She and her 455 pounds struggle every step, every day. "Right now ... I only merely exist."

But this nearly quarter-ton woman may share a genetic link with a one-ounce mouse.

"It's a way that we can illustrate using mouse models with specific genetic characteristics to dissect these processes that are so common in the human population," Dr. Philip Wood, DVM, PhD, said.

Wood created six mouse models in his lab, then inactivated fat-burning genes in each one. Some got fat. Others built up insulin resistance. Others stayed healthy.

Now, he's matching each mouse with a two-footed counterpart -- a person with the same genetic makeup. "We can sort of find the tipping point, if you will. When does obesity show up? When does diabetes show up? When does high blood pressure show up?"

The goal is to indentify people whose genes predispose them to being fat and all the diseases that follow, and find therapies to turn off those switches...