Why Do Humans Have a Hiuric Acid and A?

Humans had a mutation in uricase that raised its uric acid and o. And it happened around 15 million years ago. A hieric acid can cause high blood pressure, insolent resistance, fatty liver,. This doesn't sound good. So why the heck, why are humans? Why did we get this mutation that raised our uric asinos and a? That takes me back to when the mutation occurred.