XXYLT1 (Xyloside Xylosyltransferase 1): XXYLT1 is involved in the post-translational modification of proteins through the addition of xylose to the serine residues of proteoglycans, a key step in the biosynthesis of glycosaminoglycan chains. This modification is crucial for the function of proteoglycans in the extracellular matrix, affecting cell signaling, adhesion, and migration. Mutations in XXYLT1 can disrupt proteoglycan function and have been linked to developmental abnormalities, underscoring its importance in cellular function and development....