PMM2-CDG, formerly known as congenital disorder of glycosylation type 1a, is a rare multisystem disorder that involves a normal, but complex, chemical process known as glycosylation. Glycosylation is the process by which sugar chains (glycans) are created, altered and chemically attached to certain proteins or fats (lipids). When these sugar molecules are attached to proteins, they form glycoproteins. Glycoproteins have varied important functions within the body and are essential for the normal growth and function of numerous tissues and organs. PMM2-CDG can affect virtually any part of the body, although most cases usually have an important neurological component. PMM2-CDG is associated with a broad and highly variable range of symptoms and can vary in severity from mild cases to severe, disabling or life-threatening cases. Most cases are apparent in infancy. PMM2-CDG is caused by mutations of the phosphomannomutase-2 (PMM2) gene and is inherited as an autosomal recessive condition.Introduction
PMM2-CDG belongs to a group of disorders known as the congenital disorders of glycosylation (CDG). CDG were first reported in the medical literature in 1980 by Dr. Jaak Jaeken, et al. More than 100 different forms of CDG have been reported in the ensuing years. PMM2-CDG is the most common form. Several different names have been used to describe these disorders including carbohydrate-deficient glycoprotein syndromes. Recently, researchers have proposed a classification system that names each subtype by the official abbreviation of its defective gene followed by a dash and CDG. Congenital disorder of glycosylation type 1a is now known as PMM2-CDG. CDG are a rapidly growing disease family and information about these disorders is constantly changing.
NORD and the European Organization for Rare Disorders (EURORDIS) have established Rare Disease Communities for several rare disorders. These disease-specific online patient communities allow patients to read information about their disease, share and read stories from other patients, and network with others in five different languages. To access the Congenital Disorders of Glycosylation (CDG) Rare Disease Community, please visit: www.rarediseasecommunities.org