Search

Glycogenosis type III is characterized by a deficiency of debranching enzyme in most tissues, and it can be detected by the inability to liberate glucose from limit dextrin. However, using this assay, the deficiency is not expressed in cultured fibroblasts from patients with glycogenosis type III. We have demonstrated that the failure to detect debranching enzyme deficiency in fibroblasts is entirely due to interference of acid alpha-glucosidase, which can also hydrolyse limit dextrin. A method is described to remove specifically acid alpha-glucosidase allowing clear discrimination between fibroblasts from patients and controls, whereas heterozygotes showed intermediate values. The results with amniotic fluid cells and chorionic villi suggest the feasibility of first- and second-trimester prenatal diagnosis of glycogenosis III.

Seventeen patients with different types of glycogen storage disease (GSD) were under observation. The type of the disease was defined from glucaemic and lactotaemic curves obtained in glucose, galactose and adrenaline tolerance tests and by biochemical analysis of liver biopsy specimens. Seven patients were found to have Type I; five patients, Type III; one patient, Type VI; and four patients, the Type IX (or X) of GSD. The serum lipoprotein (LP) content was determined in all patients using analytical ultracentrifugation. Hyperlipoproteinaemia (HLP) was found in virtually all patients. Patients with Type I of GSD were found to have Types 2b and 4 of HLP; and patients with Type III of GSD, 2b Type of HLP. 2a Type of HLP was diagnosed in patients with GSD of VI and IX (X) Types. Patients with Type III GSD, in contrast to those with GSD of other types, had enhanced levels of Sf 12-20 LP. The levels of Sf 100-400 and Sf 20-100 LP were greatly increased only in patients with Type I GSD.

The authors describe four cases of atypical forms of glycogenosis with alpha-1,4-glucosidase (acid maltase) deficiency. The results of clinical, microscopic, histochemical, enzymological and immunological studies are described. Acid maltase activity has been studied in muscle, leukocytes and fibroblasts. The authors show no difference in the properties of acid maltase; the authors study the purified enzyme from various tissues.

In the kidneys of two infants who died from glycogenosis type II (deficiency of lysosomal acid alpha-glucosidase) the activity of alpha-glucosidase at acid pH was absent only from the medulla but not the cortex. This prompted an investigation of acid and neutral alpha-glucosidases of the two zones of normal human kidney and of liver. In the kidney medulla, a single, fast migrating electrophoretic band was active at neutral but not at acid pH. In the cortex, three additional bands were detected at neutral pH and two in the liver. One slowly migrating band was unique to the cortex and active over a broad pH range. It had comparatively high sensitivity to the inhibitor turanose and high heat stability. Its properties suggested a close relationship or identity to glucoamylase of the intestinal brush border membrane and to alpha-glucosidase in leukocytes and amniotic fluid and cells.

The physico-chemical and electrophoretical properties of alpha-glucosidases from various human tissues and urine have been studied. There were some differences among Peak I enzymes (neutral alpha-glucosidases) obtained from liver, heart, muscle, kidney and urine. These differences are based on different effects of tris(hydroxymethyl)aminomethane and various thermostabilities of the Peak I enzymes. Electrophoretically, the Peak I enzyme activity at pH 6.5 from control tissues displayed a two-banded pattern except in kidney and urine. In the patient with the adult form of Pompe's disease the faster band of the Peak I enzyme from heart and muscle was not found and the slower band of the Peak I enzyme from liver was more cathodic. The results are discussed in relation to glycogenosis type II (Pompe's disease).

Isoenzyme patterns of phosphorylase in white blood cells and cultured fibroblasts of a patient affected with liver-type phosphorylase deficiency were studied. Three bands were observed with electrofocusing of white blood cells and liver from controls. In the white blood cells of the patient only two bands were observed. Patient and control fibroblasts showed two bands, probably identical to the two bands observed in the patient's white blood cells. These results indicate that the liver-type phosphorylase is not expressed in the cultured fibroblasts.

alpha-Glucosidase activity was assayed in polymorphonuclear cells and lymphocytes from human peripheral blood with 4-methylumbelliferyl-alpha-D-glucopyranoside as substrate in the presence of sodium taurocholate. The pH vs. activity curve of the alpha-glucosidase indicated that differential estimation between acid and neutral alpha-glucosidases was difficult to perform with polymorphonuclear cells, but easily accessible with lymphocytes. The use of peripheral blood lymphocytes for the enzymatic diagnosis of Pompe's disease seemed to be more reliable than the use of whole leucocytes; this also the case with a classical Pompe's patient. The lymphocytes from the parents had normal or low normal activity of acid alpha-glucosidase in the freshly isolated state, but when cultured with phytohaemagglutinin for 72 h, the stimulated lymphocytes of both parents showed about half the enzyme activity of the cultured controls. It was deemed possible in all probability to identify the carrier state by assay of the enzyme activity in phytohaemagglutinin-stimulated lymphocytes.

We describe an improved method for detecting deficiency of the acid hydrolase, alpha-1,4-glucosidase in leukocytes, the enzyme defect in glycogen storage disease Type II (Pompe disease). The procedure requires smaller volumes of blood and less time than previous methods. The assay involves the separation of leukocytes by Peter's method for beta-glucosidase and a modification of Salafsky and Nadler's fluorometric method for alpha-glucosidase.

Three patients with myophosphorylase deficiency were investigated. Two had no detectable activity, while one had 1% residual activity. The patient with 1% residual activity had 40% of the normal amount of myophosphorylase protein. No myophosphorylase protein could be detected in the other two cases. A precipitin band in the Ouchterlony double immunodiffusion test was not present in any case. This study showed that modifying the normal enzyme (without changing the molecular weight) changed the immunoprecipitin activity of the phosphorylase protein. Therefore, immunoprecipitation is not a valid technique for differentiation of the variants of myophosphorylase deficiency, and another method, for example SDS-electrophoresis, should be applied.

The physico-chemical and immunological properties of acid alpha-glucosidase from various human tissues have been studied. Heat stability of acid alpha-glucosidase from heart, liver and skeletal muscle is identical, but for kidney some different results are obtained. Identical isoelectrofocussing patterns are found for heart, liver and skeletal muscle. Furthermore, the effect of antiserum against human liver acid alpha-glucosidase on the activity of acid alpha-glucosidase from various tissues is studied. The results are discussed in relation to glycogenosis type II (Pompe's disease).