ESPE Abstracts

Background: Glycogen storage disease (GSD) is an inherited metabolic defect of metabolic defect of glycogenolysis and gluconeogenesis. Patients with GSDs are associated with endocrine abnormalities such as short stature, delayed puberty, fasting hypoglycemia, and dyslipidemia. In addition, patients with GSD 1b are also at risk of autoimmune hypothyroidism. Therefore, this study was performed to investigate endocrine complications in patients with GSD.

Methods: This study included 55 patients from 46 families diagnosed between January 1995 and December 2017: GSD type Ia (37 patients from 34 families), Ib (n=3), III (six patients from 4 families), IV (n=1), and IX (8 patients from 4 families). All patients were genetically confirmed by Sanger sequencing of the causative genes. Patients with muscle glycogenosis were excluded in the study. Clinical and endocrine characteristics were retrospectively analyzed such as height, weight, hypoglycemia, lipid profiles, and bone mineral density.

Results: The median age at diagnosis was 2.4 years (range 0.4 to 42 years). The mean height SDS at diagnosis was -1.84±1.88 (range -8.31 to 1.44). Short stature (height SDS <-2 SDS) was prevalent in GSD Ia (18/37 patients, 48.6%). The current median age was 16 years (range 0.9 to 47.8 years), and the mean height SDS at current age was -1.45±1.59 (range -7.46 to 1.34). The mean triglyceride level was 520±448.3 mg/dL at diagnosis and decreased to 346.3±390.5 mg/dL at last-follow-up (P = 0.0408). Thyroid functions were analyzed in 24 patients, resulting in within the normal reference range in all patients. Vitamin D deficiency (25-hydroxyvitamin D₃ <20 ng/mL) was found in 15 of 37 patients (40.5%). Dual-energy X-ray absorptiometry analysis was performed in 16 patients. As a result, osteoporosis (bone mineral density Z score <-2 SDS) was documented in 11 patients.

Conclusions: This study demonstrated that the patients with GSD type 1a developed significant growth retardation. In addition, other endocrine abnormalities such as dyslipidemia, osteoporosis, vitamin D deficiency can be associated in the patients. Dietary treatment with uncooked cornstarch improves growth and partially corrects the biochemical findings. Future longitudinal studies with a large number of patients may allow better understanding of factors that impact endocrine complications.