Presentation and Diagnosis of Phosphoglucomutase Deficiency Type I in a Pediatric Patient

Background: Phosphoglucomutase deficiency type 1 (PGM1) is a subtype of congenital disorders of glycosylation (CDG). The type of CDG a patient has is dependent on the gene involved. There are over 130 different types of CDGs, and the defect results in abnormal levels of glucose and galactose metabolites. The diagnosis of CDGs is made by a variety of specialized tests including DNA sequencing, transferrin isoform analysis, or isoelectric focusing. Most CDGs have no direct treatment, but certain disorders have existing therapy and others are in development. It is important to consider CDG in the evaluation of patients who have involvement of multiple organ systems given the potentially treatable nature of these disorders, and the overlap with other disorders. Case Information: We present a patient with phosphoglucomutase (PGM1) deficiency who presented with hypoglycemia and elevated liver function tests. Clinical features of PGM1-CDG involve severe liver and muscle impairment, hypoglycemia, cardiomyopathy, coagulopathies, endocrine and metabolic disorders, neurocognitive delays, and craniofacial abnormalities (cleft palate, bifid uvula, and micrognathia). Abnormal protein glycosylation produces these characteristics, and recurrent hypoglycemia occurs due to insufficient glycogen mobilization. Conclusions: We provide a thorough case history and then discuss the pathophysiology, clinical features, diagnosis, evaluation, and management of PGM1 deficiency. A summary of clinical trial data on the use of galactose supplementation in this rare disorder is provided as is a decision tree in the work-up of hypoglycemia.