Glycoproteins are essential in the production, transport, storage and regulation of thyroid
hormones. Altered glycosylation has a potential impact on thyroid function. Abnormal thyroid
function tests have been described in patients with congenital disorders of glycosylation. We
evaluated the reliability of biochemical markers and investigated thyroid function in 18
PMM2-CDG patients. We propose an expectative therapeutic approach for neonates with
thyroid abnormalities in CDG.