Mannose phosphate isomerase deficiency‐congenital disorder of glycosylation (MPI‐CDG) with cerebral venous sinus thrombosis as first and only presenting symptom: A rare but treatable cause of thrombophilia

Mannose phosphate isomerase deficiency‐congenital disorder of glycosylation (MPI‐CDG; formerly named CDG type 1b) is characterized by the clinical triad of hepatopathy, protein‐losing enteropathy, and hyperinsulinemic hypoglycemia in combination with coagulation disorder (thrombophilia, depletion of antithrombin, proteins C and S, factor XI). In the majority of patients, MPI‐CDG manifests during early infancy or childhood. Here, we present a 15‐year‐old female patient with unremarkable medical history suffering from acute cerebral venous sinus thrombosis necessitating interventional thrombectomy and neurosurgical decompression. Diagnostic work‐up of thrombophilia revealed deficiency of antithrombin (AT), proteins C and S, and factor XI. Detailed evaluation identified MPI‐CDG as the underlying cause of disease. After initiation of mannose therapy, coagulation parameters normalized. The girl fully recovered without any neurologic sequelae, and remains free of further thrombotic events or any other clinical and laboratory abnormalities on follow‐up 1 year after start of mannose treatment. In conclusion, we here present the significant case of MPI‐CDG with a severe cerebral venous sinus thrombosis as the first and only symptom of the disease. In light of the high frequency of AT deficiency on one hand, and the excellent treatability of MPI‐CDG on the other hand, CDG screening should be included as a routine analysis in all patients presenting with unexplained coagulation disorder, especially when comprising AT deficiency.