PMM2-Congenital Disorder of Glycosylation: PMM2 analysis

Diagnostic Use

PMM2-congenital disorder of glycosylation (PMM2-CDG, also known as congenital disorder of glycosylation type Ia) is an autosomal recessive disorder and is the most common form of congenital disorders of glycosylation (CDG) disorders. It presents with a broad and highly variable range of symptoms and severity, ranging from mild cases to severe, disabling or life-threatening cases. Most cases are apparent in infancy.

PMM2-CDG is caused by homozygous or compound heterozygous mutation in the PMM2 gene of chromosome 16 (16p13) encoding the phosphomannomutase-2 (PMM2) enzyme. Mutations in the gene lead to the production of an abnormal PMM2 enzyme with reduced activity. Without a functioning enzyme, glycosylation cannot proceed normally. As a result, incorrect oligosaccharides are produced and attached to proteins. The wide variety of signs and symptoms in PMM2-CDG are likely due to the production of abnormally glycosylated proteins in many organs and tissues.

The diagnosis of PMM2-CDG is typically established with a combination of carbohydrate-deficient transferring analysis and identifying pathogenic variants in the PMM2 gene.


Genetics - Molecular Pathology

Delphic Registration Code


Constituent Tests



Turnaround Time

4 weeks