Answer:
the person likely will eat more than normal, thereby developing obesity and an increased likelihood of suffering heart diseases
Explanation:
The gene (ob) in mice is a homolog of the LEP gene in humans which encodes an adipocyte-specific secreted protein called 'leptin1' that modulates different physiological processes by controlling the hormone Leptin. This hormone (Leptin) is secreted by adipose tissue in order to regulate appetite and hunger. People/mice with a defective version of the leptin/ob gene likely won't control their appetite and will eat more than normal, causing obesity, which is associated with a higher risk of developing cardiovascular diseases (for example, heart attacks).