Catalyzes the transfer of CDP-ribitol to ribitol 5-phosphate previously attached by FKTN/fukutin of to the phosphorylated O-mannosyl trisaccharide (N-acetylgalactosamine-beta-3-N-acetylglucosamine-beta-4-(phosphate-6-)mannose), a carbohydrate structure present in alpha-dystroglycan (DAG1) (PubMed:26923585). This constitutes the second step in the formation of the ribose 5-phosphate tandem repeat which links the phosphorylated O-mannosyl trisaccharide to the ligand binding moiety composed of repeats of 3-xylosyl-alpha-1,3-glucuronic acid-beta-1 (PubMed:26923585). 3-O-[Rib-ol-P-3-beta-D-GalNAc-(1->3)-beta-D-GlcNAc-(1->4)-(O-6-P-alpha-D-Man)]-Thr-[protein] + CDP-L-ribitol = 3-O-[Rib-ol-P-Rib-ol-P-3-beta-D-GalNAc-(1->3)-beta-D-GlcNAc-(1->4)-(O-6-P-alpha-D-Man)]-Thr-[protein] + CMP + H(+) Protein modification; protein glycosylation. Homodimer; disulfide-linked (By similarity). Forms a complex composed of FKRP, FKTN/fukutin, and RXYLT1/TMEM5 (By similarity). Exists also as large multimeric protein complexes (By similarity). May interact with the dystrophin-glycoprotein complex (DGC) (PubMed:17452335). The N-terminal hydrophobic domain is cleaved after translocation to the Golgi apparatus and the protein is secreted (PubMed:19900540). Localization at the cell membrane may require the presence of dystroglycan (PubMed:17452335). At the Golgi apparatus localizes to the middle-to-trans-cisternae (PubMed:12471058, PubMed:17554798). Detected in rough endoplasmic reticulum in myocytes (By similarity). Expressed in the retina, specifically in the inner segments of the photoreceptors, the outer plexiform layers, inner nuclear layers, and ganglion cell layers (at protein level) (PubMed:29416295). Expressed at highest levels in brain, lung, heart, kidney and liver (PubMed:12471058). N-glycosylated. Embryonic lethality before 12.5 dpc. Belongs to the LicD transferase family.