The condition can leave you with smooth skin where usually there would be fingernails. Here's a medical condition we hadn't come across before until recently: Anonychia congenita. Simply put, the condition is an absence of fingernails and/or toenails from birth. The condition is rare and affects people to different extents. Some miss only part of their nails, or sometimes the condition does not affect all of their finger or toenails. It is generally caused by mutations in the RSPO4 gene, responsible for the production of the protein R-spondin-4, which in turn plays a role in the development of cells and tissues, particularly in the ends of fingers and toes. The condition – though still rare – is more likely to occur in people whose parents are blood relatives. The good news is that the condition is not anything to worry about – it turns out you can live a pretty normal life without fingernails. However, people with the condition can fit false prosthetic nails to their fingers for aesthetic purposes. Source