[Nine cases of debrancher deficiency (glycogen storage disease type III) presenting muscle weakness--study on...

In nine patients aged 3 to 45 years with glycogen storage disease type III (GSD III) presenting muscle weakness, the clinical manifestations and biochemical subtype-classifications based on organ specificity or enzymatic varieties of debrancher enzyme were analyzed. All the patients developed muscle weakness since childhood. Five patients who showed muscle weakness beginning from childhood became apparently progressive during adult life. Cardiac involvements were noticed in six patients. Eight patients were diagnosed as having type IIIa and one type IIId. Our results suggest that progressive muscle weakness and cardiac symptoms are not rare in GSD III patients, especially in the patients with enzyme deficiency in muscle tissue as well as liver. Hence we recommend to measure debrancher activity in muscle tissue in order to predict the clinical prognosis of the patients with GSD III.