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N-linked glycans are synthesized by adding individual charged sugars in a specific order to the growing multi-sugar structure, or oligosaccharide. Phosphomannomutase 2 (PMM2) is required for synthesis of one of these charged sugars, mannose-1-phosphate (man-1-P) from mannose-6-phosphate (man-6-P). Without adequate pools of man-1-P (as a result of decreased activity of PMM2), synthesis of complete N-linked glycans will be affected. The early steps of this complex multistep pathway occur in the endoplasmic reticulum, followed by completion of the synthesis after the growing structure is transferred to the Golgi.