Congenital disorder of glycosylation type Ia is a congenital disorder that interferes with sugars correctly attaching to proteins in the body.
Symptoms can be present at birth and include neuromuscular abnormalities, severe developmental delay, and additional physical abnormalities.
This condition is caused by pathogenic (disease-causing) variants in the PMM2 gene and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background. For example, individuals of Ashkenazi Jewish descent have a 1 in 61 chance to be a carrier. Carriers typically do not experience any symptoms.
Other names for this condition include carbohydrate-deficient glycoprotein syndrome type Ia, Jaeken syndrome, phosphomannomutase 2 deficiency, and PMM2 deficiency.