Patients with glycogen storage disease type II and type III were recently found to excrete increased amounts of a glucose-containing tetrasaccharide dGlep[RIGHTWARDS ARROW] 6)dGlcp[RIGHTWARDS ARROW] 4)dGlep(α1 [RIGHTWARDS ARROW] 4)dGlc [Lennartson, G., Lundblad, A., Sjöblad, S., Svensson,S. and Öckerman,P.A.(1976) Biomed. Mass Spectrom. 3, 51–54]. In addition to this tetrasaccharide, urine from these patients also contains larger oligosaccharides containing only glucose. From urine of patients with glycogen storage disease type II and type III, three and four oligosaccharides respectively have been isolated. Structural studies including sugar analyses, methylation analyses, partial acid hydrolysis and optical rotation revealed that three compounds were present in the urine of both patients. Their proposed structures or partial structures are as follows:dGlcp(α1–6)dGlcp(α1–4)dGlcp(α1–4)dGlcp(α1–4)dGlc, dGlcp(α1–4)dGlcp(α1–6)dGlcp(α1–6)dGlcp(α1–4)dGlcp(α1–4)dGlc, and dGlcp-(α1–6)dGlcp(α1–4)dGlcp(α1–4)dGlcp(α1–4)dGlcp(α1–6)dGlcp(α1–4)dGlcp(α1–4)dGlc. A fourth compound has been partially characterized as a branched heptasaccharide with four (1[RIGHTWARDS ARROW]4) linkages and two (1[RIGHTWARDS ARROW]6) linkages.

Glycogen is possibly the origin of these compounds. However, the number of (1[RIGHTWARDS ARROW]6) linkages is higher than expected and may indicate a shorter distance between branches in glycogen than has been generally assumed.