What would cause a fingernail that is the same raised shape, thickness and appearance of a dog's claw?

I have a friend who has this even though all her other nails are normal. It's something she was born with and drs have ruled out any fungus and can't figure out what else it would be. It is very difficult for her to trim and it rips to the quick and bleeds rather often unless she has artificial nails over it. Due to the makeup of it, there is no way to file it down smoothly. No matter how it is trimmed if even possible (it's so thick she can't even do that without it ripping), it grows back with the same thickness and appearance. What would cause something like that?What would cause a fingernail that is the same raised shape, thickness and appearance of a dog's claw?
i would go to those doctors that take care or feet and ingrown nails and stuff that very rare ive never heard that b4What would cause a fingernail that is the same raised shape, thickness and appearance of a dog's claw?
My guess is fungus. It must be one they can't identify.