Phosphomannomutase 2（PMM2) is a member of the eukaryotic PMM family. Phosphomannomutase 2 is involved in the synthesis of the GDP-mannose and dolichol-phosphate-mannose required for a number of critical mannosyl transfer reactions. PMM2 catalyzes the isomerization of mannose 6-phosphate to mannose 1-phosphate. PMM2 mutations are linked to congenital disorders of glycosylation（CDG)-Ia， an autosomal recessive disorder characterized by central nervous system dysfunction and multiorgan failure.
