Lack of an alpha-1,4-glucan: alpha-1,4-glucan 6-glycosyl transferase in a case of type IV glycogenosis.

Abstract

Although "amylopectinosis" was originally described in 1952 as a type of glycogen storage disease,' very few additional cases have been observed in the intervening years either because the disease is very rare or because it is not easily recognized clinically. The original designation of the disease was based on the accumulation in the liver of a polysaccharide whose structure resembled that of amylopectin rather than that of glycogen. Thus, the polysaccharide had long outer chains with relatively few branch points and was highly chromogenic with I2-KI; the I2 complex had an absorption peak at 530 mji as compared to 460 msA for glycogen. The cause of the accumulation of such an unusual polysaccharide was postulated to be a relative deficiency of the branching enzyme. 12 No enzymic assays could be performed. A detailed clinical description of this case was published by Andersen,3' 4 and the observations on polysaccharide structure were reported by Illingworth and Cori.' A second case of Type IV glycogenosis was described by Sidbury et al. in 1962,5 and a third case by Holleman et al. in 1966.6 We recently received tissues taken by biopsy from a 19-month-old child (M. G.) suspected of having Type IV glycogenosis. The purpose of this paper is to describe some new chemical and enzymatic findings which have been made on this material. A full clinical report of the case will be presented by Donnell.7 Methods and Results.-The liver had a polysaccharide content of 3.5 per cent, and the isolated material was shown to be highly chromogenic with 12-KI (maximum absorption at 525 mIu), and to have long outer chains (degraded by phosphorylase to the extent of 47%) and a relatively low branch point percentage (6.0%). Muscle samples taken upon two different occasions had polysaccharide contents of 0.5 and 1.0 per cent. Unlike the polysaccharide from liver, that from muscle contained 7.4 per cent branch points and could be degraded by phosphorylase to the extent of 36 per cent, a value characteristic of glycogen. The absorption spectrum of the

Cell migration and chimerism after whole-organ transplantation: The basis of graft acceptance

“…In GSD IV, a deficiency of the branching enzyme alpha-1,4-glucan:alpha-1,4-glucan 6-glycosyltransferase (50) is responsible for the widespread accumulation intracellularly and extracellularly of an insoluble and irritating amylopectin-like polysaccharide (50,51).…”

Hepatic and neuromuscular forms of glycogen storage disease type IV caused by mutations in the same glycogen-branching enzyme gene.

“…The disease is also referred to as amylopectinosis, because the abnormally stored glycogen has fewer branch points, more ␣ 1-4 linked glucose units, and longer outer chains, resulting in a structure resembling amylopectin (1)(2)(3). Clinically, GSD-IV is a heterogeneous disorder with remarkable clinical variability.…”

A complex rearrangement in GBE1 causes both perinatal hypoglycemic collapse and late-juvenile-onset neuromuscular degeneration in glycogen storage disease type IV of Norwegian forest cats

“…GBE is an enzyme of glycogen synthesis, deficiency of which results in tissue deposition of an abnormal and poorly soluble poly-glucan resembling amylopectin [2,3]. The clinical presentation in humans is quite heterogeneous [4].…”