Recent experimental data show that some human genetic diseases are due to mutations in proteins which influence their trafficking and lead to retaining of proteins in the endoplasmic reticulum or their unproper processing. In this paper a hypothesis is proposed that these mutations are connected with an incomplete protein folding, blocking it at the stage of the kinetic molten globule or even earlier. If so, the specific drugs against these diseases may be ligands and other factors which facilitate the correct protein folding.