What cellular process do glycogen storage diseases affect besides glycogenesis?

Glycogen storage diseases primarily affect the metabolism of glycogen, which includes disruptions in both glycogenesis (the synthesis of glycogen from glucose) and glycogenolysis (the breakdown of glycogen into glucose). These diseases are caused by genetic mutations that impair the enzymes responsible for these processes.

When glycogenolysis is affected, the body's ability to mobilize glucose from stored glycogen is compromised. As a result, individuals with these conditions may experience hypoglycemia, especially during fasting or strenuous exercise, since they cannot effectively release glucose into the bloodstream when needed. This illustrates the integral nature of glycogenolysis in maintaining blood glucose levels and energy availability.

Therefore, the correct answer highlights the significant impact that glycogen storage diseases have not only on glycogenesis but also on glycogenolysis, making it a key process that is disrupted in these conditions.