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EDEM3-Congenital Disorder of Glycosylation (EDEM3-CDG)

Also known as ER Degradation Enhancing Alpha-Mannosidase Like Protein 3

A rare, multisystemic, inherited condition caused by an abnormal protein which cannot effectively target misfolded glycoproteins. Symptoms manifest in infancy and childhood, including intellectual disability, developmental and speech delays, mild facial abnormalities, hypotonia (low muscle tone), behavioral problems, failure to thrive, and age-resolving central apnea.

Symptoms

EDEM3-CDG is a very rare inherited condition that affects multiple parts of the body. There are only 12 EDEM3-CDG patients from 7 families published in the medical literature.

Individuals with EDEM3-CDG typically develop signs and symptoms of the condition during infancy and childhood. Affected individuals exhibit developmental delay, speech delay, mild facial abnormalities, and about 50% have behavioral abnormalities (primarily hyperactivity, attention deficit, and anxiety). Approximately 25% have failure to thrive requiring G-tube feeds and another 25% have central apnea that resolves with age.

Diagnosis

EDEM3-CDG affects N-glycosylation, but the patients tested to date have normal transferrin glycosylation, however, they may have global glycosylation abnormalities detected on N-glycan analysis. The ultimate diagnosis is genetic testing in blood. Individuals with EDEM3-CDG have two faulty copies of the EDEM3 gene

Treatment and Prognosis

To date, there are no known specific treatment options for EDEM3-CDG. Treatment is aimed at the management of symptoms and the prevention of complications. Patients seem to have a good life expectancy. The oldest EDEM3-CDG patient that has been described in the medical literature was 33 years old in 2021.