Glycogen storage disease type IV, amylopectinosis.

Classification of the glycogen storage diseases according to the underlying enzyme defect has added considerably to our understanding of this group of diseases. Of the 6 types in which the biochemical abnormality has been characterized, the least common appears to be type IV, amylopectin-osis. The first case was described by Andersen in 1952, and the glycogen present in the liver and other organs was shown by Illingworth and Cori (1952) to possess abnormally long outer and inner chains of glucose units. For this reason, Cori (1954) suggested that the enzyme, oc-1,4-glucan: oc-1,4 glucan 6-glycosyl transferase, effective in transferring chains of glucose units to form new branches in the glycogen molecule, was absent. Despite this clear recognition of a new syndrome, few cases have since been reported. A second was diagnosed during life by Sidbury et al. in 1962, and a brief account of a third, also diagnosed in life, was given 3 years later (Mortimer, 1965). Since then, descriptions of 3 more have appeared, 2 of whom were sibs (Holleman, van der Haar, and de Vaan, 1966; Brown and Brown, 1966; Fernandes and Huijing, 1968). In the last 2, absence or gross deficiency of the branching enzyme was conclusively demonstrated by assay. The present article is concerned with the third case to be reported, of which only preliminary details have previously been given (Mortimer, 1965). Glycogen storage disease was suspected at 8 months of age because of gross hepatomegaly associated with enlargement of the spleen. Investigations of carbohydrate metabolism supported the diagnosis, which was confirmed by an examination of a biopsy specimen of liver. The sparing solu-bility in water of the glycogen extracted from the liver, and the blue colour of its complex with iodine suggested an amylopectin-like structure, which was proved by a more complete examination. at term in hospital on March 4, 1964, after a normal pregnancy and delivery, birthweight 3515 g. For the first 5 weeks he was breast-fed, with dried milk supplements , but thereafter he was fully artificially fed. He gained weight satisfactorily till he was 6 months old, when he began to vomit and ceased to gain. At 8 months of age, he was admitted to hospital because of anorexia as well as persistent vomiting occurring at least once every day. He was then noted to be an alert and active, but wasted child, his weight being on the 3rd centile. The liver, which …