Low bone mass in glycogen storage disease type 1 is associated with reduced muscle force and poor metabolic control.

OBJECTIVE To study the relation between muscle force, bone mass, and metabolic control in patients with glycogen storage disease type (GSD 1). STUDY DESIGN Distal radius bone mass and density were evaluated in 19 patients with GSD 1 (15 GSD 1a, 4 GSD 1b) by means of peripheral quantitative computed tomography. Grip force was quantified with a dynamometer. RESULTS Height, weight, bone mass, and grip force were significantly decreased in the patients with GSD 1a, mainly as the result of low values in the poorly controlled subgroup. Boys had lower bone mass than girls. Patients with GSD 1b had higher values for bone mineral density in the trabecular compartment. In most of the study participants bone mass appeared to be adequately adapted to the mechanical requirements imposed by muscle contraction. However, 3 patients with GSD 1a had evidence for a low bone mass. CONCLUSIONS In GSD 1, both reduced muscle strength and a direct disease effect can contribute to low bone mass. The quality of treatment is crucial to prevent disturbances in musculoskeletal development.