Over 100 types of congenital disorders of glycosylation (CDG) have been reported and the number is rapidly increasing. However, each type is very rare and is problematic to diagnose. Mannosyl-oligosaccharide glucosidase (MOGS)-CDG (CDG type IIb) is an extremely rare CDG that has only been reported in three patients from two unrelated families. Using targeted exome sequencing, we identified another patient affected by this condition. This patient had increased serum trisialotransferrin levels. Importantly, a review of the features of all four patients revealed the recognizable clinical hallmarks of MOGS-CDG. The distinct dysmorphic features of this condition include long eyelashes, retrognathia, hirsutism, clenched overlapped fingers, hypoventilation, hepatomegaly, generalized edema, and immunodeficiency.