What Is Congenital Disorder of Glycosylation, MPI-Related?

Congenital disorder of glycosylation (CDG) MPI-related, caused by mutations in the MPI gene, is an inherited metabolic disorder that impairs the production of glycoproteins, which are proteins that have attached carbohydrates. This condition affects many systems of the body, but unlike most CDG disorders, it does not impact the nervous system. Intellect is not impacted in individuals with congenital disorder of glycosylation, MPI-related.

If left untreated, congenital disorder of glycosylation, MPI-related can cause a wide array of problems, including chronic diarrhea, failure to grow at the expected rate, loss of protein from the body, severe nausea and vomiting, low blood sugar (hypoglycemia), difficulty in forming blood clots, and liver disease. Because congenital disorder of glycosylation, MPI-related can be life-threatening, early diagnosis and treatment are important.

How Common Is Congenital Disorder of Glycosylation, MPI-Related?

CDG, MPI-related has been reported in less than 50 individuals, and its prevalence is unknown.

How Is Congenital Disorder of Glycosylation, MPI-Related Treated?

CDG, MPI-related is treated with oral supplements of mannose, a sugar. Individuals with the disease who begin mannose treatment show improvement in most of the symptoms associated with the condition. Treatment with mannose is lifelong and for some, heparin treatment can improve gastrointestinal issues that cause the body to lose protein. In some cases, liver disease worsens even with treatment, but in one case, symptom improvement was observed after a successful liver transplant.

What Is the Prognosis for an Individual with Congenital Disorder of Glycosylation, MPI-Related?

With early and regular treatment, an individual with CDG, MPI-related can live a near-normal life. Without treatment, the disease can be fatal. Generally, the prognosis varies depending on the severity of symptoms and the response to mannose treatment.

Other names for
congenital disorder of glycosylation, MPI-related

  • Congenital disorder of glycosylation 1b (CDG-1b)
  • Gastrointestinal type CDG
  • MPI deficiency
  • Mannosephosphate isomerase deficiency
  • SLSJ syndrome
  • Saguenay-Lac Saint-Jean syndrome


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  • Sparks et al., 2017, https://www.ncbi.nlm.nih.gov/books/NBK1332/
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