Mannose phosphate isomerase-congenital disorder of glycosylation leads to asymptomatic hypoglycemia

Background

Mannose phosphate isomerase deficiency-congenital glycosylation disorders (MPI-CDG) is a rare autosomal recessive disorder caused by pathogenic variants in the MPI gene and characterized by digestive, hepatic, and endocrine-related symptoms. Herein, we reported a case of a 4-month-old baby with MPI-CDG confirmed by genetic testing.

Case summary

Based on the age of the child and the present clinical symptoms (feeding difficulties, intractable diarrhea, vomiting, hepatosplenomegaly, recurrent hypoglycemia, coagulation disorder, and hypoproteinemia under the premise of anti-infection therapy), congenital glycosylation disorder was suspected, which was then confirmed by genetic testing. Her father carried a heterozygous deletion variant of exons 1–2 of the MPI gene, while her mother carried a heterozygous variant of C. 422C > T variant. It was suspected that a biallelic pathogenic variant of the MPI gene caused the CDG.

Conclusion

MPI-CDG should be considered in infancy with unexplained hypoglycemia and recurrent digestive and endocrine system involvement. Also, if evident symptoms are present, a gene examination should be performed, as this could speed up the diagnosis assuring timely treatment.