These results suggest that the levels of CDP-ribitol might be one of the limiting factors of this O-mannosylation and the supplement of ribitol or ribose can increase the levels of CDP-ribitol, thus enhancing synthesis of matriglycan as a treatment for dystroglycanopathies caused by mutations of FKRP. Here, FKRP is linked to neuromuscular disease caused by qualitative or quantitative defects of alpha-dystroglycan.