Is there a fundamental limit on the key distribution distance in quantum cryptography?

Is there a fundamental limit on the key distribution distance in quantum cryptography? Are there quantum key distribution protocols approaching this limit and how close can they approach this limit? The answer to the first question is both yes and no. A general answer to the first question can be given without considering a particular quantum key distribution protocol and its implementation. The answer to the second question is given by a particular protocol for which the distribution distance is close to the theoretical limit and the achievement of this value is limited by our possibilities of correcting errors using classical codes rather than by the quantum key distribution protocol itself.