Glycogen Storage Disease, Types II, III, VIII, and IX

CORI DIVIDED the syndrome of glycogen storage disease into various types according to the enzymatic deficiency involved.1This classification has three immediate advantages. It rests on the most basic, most precise, and least overlapping parameter known at the present time. It permits delineation of a clinical picture indicative of a particular type. It allows the addition of newly recognized types without reshuffling of the whole system. Table 1 summarizes the current state of this classification. Types I through VI of this classification are already widely accepted. Type VII comprises deficiencies of phosphoglucomutase. This enzyme's activity was found decreased in the skeletal muscle of one patient.2In another study a patient is mentioned with a low level of phosphoglucomutase activity in both muscle and liver.3Table 1 further includes as types VIII and IX our patients described below, whose low liver phosphorylase activity seems the result of different