Nutritional management and geno-phenotyping of clinical nutrition in patients with glycogen storage diseases type VI and IX.

Objective: Glycogen storage diseases type VI (GSD-VI) and type IX (GSD-IX) are rare inherited metabolic disorders caused by enzyme deficiencies that disrupt glycogen metabolism. The aim of this study was to analyze the clinical features, nutritional management and geno-phenotyping of clinical nutrition in a cohort of patients with GSD-VI and GSD-IX.

Methods: A retrospective cohort study was conducted with 16 patients with GSD-VI and GSD-IX. Demographic characteristics, clinical and laboratory findings, and nutritional treatment outcomes were collected and analyzed.

Results: The mean patient age was 10.57 years (±4.81). The distribution of the diagnoses was as follows: GSD-IXa (3), GSD-IXb (6), GSD-IXc (1), and GSD-VI (6). The average age at diagnosis was 36.5 months (±42.2) (13-114 months) in the GSD-VI group. Among the GSD-IX subgroups, the mean age at diagnosis varied: 23.3months (±4.16) for GSD-IXa, 35.7months (±17.5) for GSD-IXb, and 78months for GSD-IXc. Over the course of the study (4.5 ± 1.77 years), protein intake in GSD VI patients increased by 1.05 g/kg/day (91.3% increase), while in GSD IX patients, it rose by 1.09 g/kg/day (94% rise). Uncooked cornstarch (UCS) started at 1 g/kg/day for GSD-VI and 0.85 g/kg/day for GSD-IX, later reduced to 0.71 g/kg/day (29% decrease) and 0.52 g/kg/day (60% reduction), respectively.

Conclusions: Overall, this paper provides valuable insights into managing GSDVI and GSDIX patients, emphasizing the role of a high-protein diet aligned with the disease's pathophysiology and the potential of genotyping to enhance nutritional treatment protocols.