The following is a summary of “Endogenous Glucose Production in Patients With Glycogen Storage Disease Type Ia Estimated by Oral D-[6,6-2H2]-glucose,” published in the February 2024 issue of Endocrinology by Rossi, et al.

Glycogen storage disease type Ia (GSDIa) is a metabolic disorder characterized by impaired endogenous glucose production (EGP), necessitating ongoing monitoring due to treatment advancements. Stable isotope tracers offer a potential method for reliable EGP assessment. For a study, researchers sought to prospectively evaluate the rate of appearance of endogenous glucose into the bloodstream (R_a) in patients with GSDIa following a single oral dose of D-[6,6-²H₂]-glucose.

Ten adult GSDIa patients and ten age-, sex-, and body mass index-matched healthy volunteers (HVs) were enrolled. Each participant underwent three oral glucose tracer tests: preprandial/fasted, postprandial, and randomly fed states. Dried blood spots were collected at intervals up to 120 minutes post-D-[6,6-²H₂]-glucose administration.

In fasted HVs, glucose R_a was consistent with previous findings. Preprandial/fasted GSDIa patients exhibited significantly higher time-averaged glucose R_a compared to HVs, while postprandial HVs showed higher R_a compared to fasted HVs (P < .05). A progressive decrease in glucose R_a was observed in preprandial/fasted GSDIa patients, correlating with changes in capillary glucose levels (P < .05).

The study, utilizing oral D-[6,6-²H₂] glucose, provided the first quantification of glucose R_a in GSDIa patients. While the test reliably estimates EGP under unaffected fasting tolerance conditions, it did not distinguish between contributions from endogenous and exogenous sources. Further longitudinal monitoring, especially following novel genome-based treatments, was warranted in GSDIa patients, potentially enabling discontinuation of nocturnal dietary management.

Reference: academic.oup.com/jcem/article/109/2/389/7266790