The Internet’s beloved Grumpy Cat died on Tuesday, at age 7, from complications following a urinary tract infection. The lovable grump, with her permanently “frowning” face, became an internet sensation at just 5 months old, when a photo of her was posted on Reddit back in 2012. [6 Secrets to Unlocking Your Cat’s Personality] In fact, Grumpy Cat’s real name was Tardar Sauce, and she wasn’t really frowning or grumpy all the time. Instead, her dour expression was caused by a combination of an underbite and feline dwarfism, the latter of which is the result of a genetic mutation that can lead to growth problems and abnormal body proportions. But the cause of the cat’s death was complications from a urinary tract infection (UTI). In cats, urinary tract diseases can have multiple causes, including infections, inflammation, diet and behavioral issues, according to Cornell University. Urinary tract diseases in cats aren’t uncommon, and surveys have suggested they are the No.1 reason cats are brought to the vet, according to Cornell. Grumpy Cat might be gone from our lives, but her displeased expression will live on forever in our memes … and her merchandise (and a Christmas movie made about her). Image Gallery: Cats that Glow in the Dark Photos: Ancient Cat Remains Tell the Tale of Kitty Domestication In Photos: America’s Favorite Pets Originally published on Live Science.