Utilization of cornstarch in glycogen storage disease type Ia.
OBJECTIVE
Uncooked cornstarch (UCCS) is used widely for the treatment of patients with glycogen storage disease type I (GSD-I). Previous studies suggested that glucose absorption may be impaired in GSD-I. In order to measure utilization of UCCS in young adults with GSD-Ia and healthy controls, we used a C-breath test based on the natural enrichment of C in UCCS.


METHODS
Open, not randomized, prospective interventional study.


METHODS
Following 1 g/kg UCCS, we studied eight subjects with GSD-Ia (7 males, 1 female; mean age 28.3 years, range 16-42 years) and 15 healthy controls (10 males, 5 females; mean age 23.5 years, range 19-36 years). Breath samples for analysis of CO enrichment were collected at baseline and at 30-min intervals for 6 h or until hypoglycaemia occurred. Indirect calorimetry was used to measure respiratory gas exchange. Intermediate metabolites, lipids and glucose were measured in plasma. Breath H concentrations were measured as an indicator of malabsorption.


RESULTS
Cumulative utilization over 6 h was significantly higher in controls (18.35 +/- 6.2% of total carbohydrate intake) than in subjects with GSD-Ia (11.5 +/- 4.7%) (P < 0.02). However, utilization of UCCS was virtually identical up to 2.5 h. Two subjects with GSD-Ia fulfilled the criteria for malabsorption.


CONCLUSIONS
Starch digestion and absorption are not impaired in GSD-Ia. However, overall utilization of UCCS appears to be lower in GSD-Ia, which is most likely secondary to perturbed intermediary metabolism. There are important implications for treatment of this disorder. Ways to improve the efficacy of UCCS in GSD-I are needed.
Bodamer
Olaf A
OA
Biochemistry, Metabolism, Endocrinology Unit, Institute of Child Health, Great Ormond Street Hospital for Children, NHS Trust, London, UK. olaf.bodamer@univie.ac.at
Feillet
Francois
F
Lane
Rebecca E
RE
Lee
Philip J
PJ
Dixon
Marjorie A
MA
Halliday
Dave
D
Leonard
James V
JV
D000293:Adolescent; D000328:Adult; D001944:Breath Tests; D002245:Carbon Dioxide / Q000032:analysis; D016022:Case-Control Studies; D005260:Female; D005953:Glycogen Storage Disease Type I / Q000378:metabolism*; D006801:Humans; D006859:Hydrogen / Q000032:analysis; D008297:Male; D011446:Prospective Studies; D013213:Starch / Q000378:metabolism*
D002245:Carbon Dioxide; D006859:Hydrogen; D013213:Starch