The clinical spectrum of phosphomannose isomerase deficiency, with an evaluation of mannose treatment for CDG-Ib.

Phosphomannose isomerase (PMI) deficiency or congenital disorders of glycosylation type Ib (CDG Ib) is the only CDG that can be treated. Despite variable severity leading to dramatically different prognoses, clinical presentation is relatively homogeneous with liver and digestive features associated with hyperinsulinism and inconstant thrombosis. A feature of CDG is that coagulation factors are decreased. In our experience, mannose given orally at least 4 times per day not only transformed lethal CDG Ib into a treatable disease, but also improved the general condition and digestive symptoms of all reported patients but one. Liver disease, however, still persisted. Heparin can be used as an alternative to mannose in certain patients, particularly in the treatment of enteropathy.