The clinical improvement of growth of this child with PMM2-CDG following rhIGF-1 therapy provides further evidence for the importance of glycosylation in the GH-IGF cascade and suggests that rhIGF-1 may be a novel treatment for growth failure in PMM2-CDG reversing the loss of growth potential that has been observed during the first 2 years of life.12 Further study of the role of rhIGF-1 therapy in CDG is warranted. Here, GH1 is linked to congenital disorder of glycosylation.