[Pompe disease : anesthesiological special features]. / Morbus Pompe : Anästhesiologische Besonderheiten.

Pompe disease is a very rare disorder of glycogen metabolism. Due to a deficiency of the enzyme glucosidase glycogen accumulates inside the lysosomes. The clinical picture varies widely as a consequence of varying participation of skeletal and heart muscle. In adults respiratory insufficiency can occur which must be taken into consideration during anesthesiology procedures for affected patients. This case report describes a 60-year-old patient scheduled for punch biopsy of the prostate.

Molecular features of 23 patients with glycogen storage disease type III in Turkey: a novel mutation p.R1147G associated with isolated glucosidase deficiency, along with 9 AGL mutations.

Glycogen storage disease type III (GSD III) is an autosomal recessive disorder caused by deficiency in the glycogen debranching enzyme (gene symbol: AGL) with two enzyme activities: transferase and glucosidase. A missense mutation causing isolated glucosidase deficiency has never been reported. In this study, we examined 23 patients of Turkish ancestry and identified a novel missense mutation p.R1147G with isolated glucosidase deficiency, along with nine AGL mutations: six nonsense mutations (p.W373X, p.R595X, p.Q667X, p.Q1205X, p.W1327X and p.Q1376X), one deletion (c.1019delA) and two splicing mutation (c.293+2T>G and c.958+1G>A). As p.R1147G impaired glucosidase activity, but maintained transferase activity in vitro, a 12-year-old girl homozygous for p.R1147G was diagnosed with having isolated glucosidase deficiency. Of nine other mutations, p.W1327X and c.1019delA were recurrent, whereas seven mutations were novel. Six patients with p.W1327X were all from two nearby cities on the East Black Sea and shared the same AGL haplotype, indicating a founder effect in Turkish patients. Patients with the same mutations had identical haplotypes. Our results provide the first comprehensive overview of clinical and molecular features of Turkish GSD III patients and the first description of the missense mutation associated with isolated glucosidase deficiency.

An in vitro model of polycystic liver disease using genome-edited human inducible pluripotent stem cells.

In the developing liver, bile duct structure is formed through differentiation of hepatic progenitor cells (HPC) into cholangiocytes. A subtype of polycystic liver diseases characterized by uncontrolled expansion of bile ductal cells is caused by genetic abnormalities such as in that of protein kinase C substrate 80 K-H (PRKCSH). In this study, we aimed to mimic the disease process in vitro by genome editing of the PRKCSH locus in human inducible pluripotent stem (iPS) cells. A proportion of cultured human iPS cell-derived CD13+CD133+ HPC differentiated into CD13- cells. During the subsequent gel embedding culture, CD13- cells formed bile ductal marker-positive cystic structures with the polarity of epithelial cells. A deletion of PRKCSH gene increased expression of cholangiocytic transcription factors in CD13- cells and the number of cholangiocytic cyst structure. These results suggest that PRKCSH deficiency promotes the differentiation of HPC-derived cholangiocytes, providing a good in vitro model to analyze the molecular mechanisms underlying polycystic diseases.

Characterization of the molecular defect in infantile and adult acid alpha-glucosidase deficiency fibroblasts.

Different clinical expressions of acid alpha-glucosidase deficiency have been described. The present study was undertaken to investigate the basic metabolic defect in the infantile and adult forms of the disease. Acid alpha-glucosidase (EC 3.2.1.20) was purified from normal and from adult acid alpha-glucosidase deficiency fibroblasts. The pH optimum; Michaelis constant; electrophoretic mobility in starch; thermal denaturation at pH 4.0 and 7.0; and inhibition by turanose, alpha-methylglucoside and trehalose were the same in purified enzyme from normal and mutant cells. Placental acid alpha-glucosidase was purified to, or near, homogeneity. Monospecific antibodies raised against the enzyme in each of three enzyme peaks obtained from the last purification step were found to cross-react with the enzyme of all three peaks, and with purified, normal fibroblast enzyme. Cross-reacting material (CRM) also was identified in fibroblast lysates from normal subjects and from both forms of acid alpha-glucosidase deficiency. The amount of CRM in the adult form appeared to be significantly less than in normal cells or cells from the infantile form. Enzyme activity was demonstrated in the immune complexes of the normal and adult acid alpha-glucosidase deficiency fibroblasts, but not of the infantile form. Competition for antibody binding sites was observed between normal and both types of mutant enzymes. The findings indicate that this case of infantile acid alpha-glucosidase deficiency is the result of a structural gene mutation which causes the synthesis of a catalytically inactive (CRM-positive) enzyme protein. It appears that in the adult form, the mutation causes a reduction in the amount of the enzyme protein present in the cells.

Clinical diversity in glycogenosis type II. Biosynthesis and in situ localization of acid alpha-glucosidase in mutant fibroblasts.

The molecular basis of clinical diversity in glycogenosis type II (Pompe's disease) was investigated by comparing the nature of acid alpha-glucosidase deficiency in cultured fibroblasts from 30 patients. Biosynthetic forms of acid alpha-glucosidase with different molecular mass were separated electrophoretically and identified by immunoblotting. Immuno-electron microscopy was employed to determine the intracellular localization of mutant enzyme. Our studies illustrate that maturation of acid alpha-glucosidase is associated with transport to the lysosomes. Deficiency of catalytically active mature enzyme in lysosomes is common to all clinical phenotypes but, in the majority of cases, is more profound in early onset than in late onset forms of the disease. Thus, the results suggest that the clinical course of glycogenosis type II is primarily determined by the amount of functional acid alpha-glucosidase. The role of secondary factors can, however, not be excluded because three adult patients were identified with very low activity and little enzyme in the lysosomes.

A lysosomal storage disorder in mice characterized by a dual deficiency of sphingomyelinase and glucocerebrosidase.

Lipid and lysosomal enzyme levels in the tissues of a strain of mice afflicted with an autosomal rescessive neuroviscereal storage disorder were examined. Sphingomyelinase and glucocerebrosidase activities were consistently diminished in a wide variety of tissues obtained from the affected mice. The activities of these enzymes were clearly attenuated in new-born mice, which at this age, were otherwise indistinguishable from littermates and age-matched controls. The deficiency of sphingomyelinase was more pronounced than glucocerebrosidase. There was progressive accumulation of sphingomyelin, glucocerebroside, lactosylceramide and unesterified cholesterol in the tissues of these mice in the postnatal period. Gangliosides GM2 and GM3 accumulated in the brain of the animals, and GM3 and asialo-GM2 were stored in the liver. Furthermore, there was a large increase in the quantity of hepatic bis(monoacylglycero)phosphate. The accumulation of lipids was parallelled by a progressive elevation in the activity of several lysosomal hydrolases in various tissues. Heterozygous mice were biochemically indistinguishable from normal controls. The phenotypic manifestations in these metabolically mutated animals are compared with those in Niemann-Pick disease and Gaucher's disease in humans.

Canine glycogen storage disease type II. A biochemical study of an acid alpha-glucosidase-deficient Lapland dog.

A biochemical study was performed in a Lapland dog suspected of glycogen storage disease type II (acid alpha-glucosidase deficiency, Pompe's disease). Glycogen content was substantially elevated in heart and skeletal muscle but not in the liver. Severely reduced activities of acid alpha-glucosidase (EC 3.2.1.20) were found in heart, skeletal muscle, liver and cultured tongue fibroblasts. The deficiency was located in the glycoprotein fraction, which supported its lysosomal origin. The electrophorogram showed after acid incubation that the affected dog was missing the activity band, while after neutral incubation the pattern was similar to control. The obtained biochemical data are compared with the known data of the human pathology.

Sec63 and Xbp1 regulate IRE1α activity and polycystic disease severity.

The HSP40 cochaperone SEC63 is associated with the SEC61 translocon complex in the ER. Mutations in the gene encoding SEC63 cause polycystic liver disease in humans; however, it is not clear how altered SEC63 influences disease manifestations. In mice, loss of SEC63 induces cyst formation both in liver and kidney as the result of reduced polycystin-1 (PC1). Here we report that inactivation of SEC63 induces an unfolded protein response (UPR) pathway that is protective against cyst formation. Specifically, using murine genetic models, we determined that SEC63 deficiency selectively activates the IRE1α-XBP1 branch of UPR and that SEC63 exists in a complex with PC1. Concomitant inactivation of both SEC63 and XBP1 exacerbated the polycystic kidney phenotype in mice by markedly suppressing cleavage at the G protein-coupled receptor proteolysis site (GPS) in PC1. Enforced expression of spliced XBP1 (XBP1s) enhanced GPS cleavage of PC1 in SEC63-deficient cells, and XBP1 overexpression in vivo ameliorated cystic disease in a murine model with reduced PC1 function that is unrelated to SEC63 inactivation. Collectively, the findings show that SEC63 function regulates IRE1α/XBP1 activation, SEC63 and XBP1 are required for GPS cleavage and maturation of PC1, and activation of XBP1 can protect against polycystic disease in the setting of impaired biogenesis of PC1.

Selective vacuolar myopathy with atrophy of type II fibers. Occurrence in a childhood case of acid maltase deficiency.

A 12-year-old boy being examined for vague chest pains was found to be suffering from acid maltase deficiency. Unlike previously reported cases in which vacuolization was most commonly noted in type I fibers, type II fibers were selectively involved in this patient and were atrophic Type I fibers were spared, or occasionally contained one or more small globular structures consisting of large, complex aggregates of lysosomal profiles.

Late-onset acid maltase deficiency. Detection of patients and heterozygotes by urinary enzyme assay.

Daily urinary excretion of acid maltase (12.78 +/- 2.10 units/24 hr/mg of creatinine, in 11 normal adults) was significantly decreased in ten patients with late-onset acid maltase deficiency (1.33 +/- 0.16 units/24 hr; P less than .001) and 11 heterozygotes (3.27 +/- 0.62 units/24 hr; P less than .001). Maximal inhibition of urinary acid maltase activity by antibodies against human placental enzyme was 53% in controls, 30% in heterozygotes, and virtually absent in patients. Investigation of pH curves and enzyme inhibition by antibodies confirmed the presence in the kidney of an immunologically distinct "extra" maltase enzyme active at acid pH. Whether acid maltase in normal urine originates in the kidney or cells of the lower urinary tract, the enzyme defect seems to be expressed in these cells in late-onset acid maltase deficiency.

Infantile and adult-onset acid maltase deficiency occurring in the same family.

A 16-week-old girl died from the infantile form of acid maltase deficiency (Pompe disease, acid alpha-glucosidase deficiency). Her paternal grandfather was well until the age of 53 years, when he started to suffer from the adult-onset form of the same enzyme deficiency. This observation suggests that the infantile and adult-onset forms of acid maltase deficiency are genetically related.

Lysosomal glycogen storage disease without acid maltase deficiency.

We studied two brothers with lysosomal glycogen storage disease without acid maltase deficiency in skeletal muscle. Although no specific biochemical defect was identified, a characteristic clinical picture emerged from evaluation of these siblings and two other previously reported patients. The syndrome is manifested by proximal muscle weakness, hypertrophic cardiomyopathy, probable intellectual impairment, and possible liver involvement.

Improvement of muscle function in acid maltase deficiency by high-protein therapy.

Progressive muscle weakness in acid maltase deficiency (AMD) is associated with intralysosomal accumulation of glycogen and altered myofibrillar morphology. A rapid fall in circulating branched chain amino acids after protein ingestion in a child with AMD suggested that increased net muscle protein catabolism may play a part in the pathogenesis of this condition. To reduce this muscle catabolism, the patient was treated with a high-protein diet for 12 months. This has reversed the weakness and wasting, with improvement in muscle function, exercise tolerance, and growth.

Residual acid maltase activity in late-onset acid maltase deficiency.

Residual acid maltase activity was found by a sensitive fluorometric assay in muscle biopsies from 15 patients with late-onset acid maltase deficiency (mean, 6.91 percent; range, 2.4 to 12.2) but not in biopsy or autopsy muscle from three patients with the infantile form. Electrophoresis, kinetic characteristics, and subcellular fractionation indicated that the residual activity was lysosomal acid maltase and not a contaminating isozyme of neutral maltase. There was no correlation between the amount of residual acid maltase activity and the severity of the clinical picture or glycogen accumulation. The presence of acid maltase activity in muscle, liver, and, to a greater extent, leukocytes in late-onset but not infantile acid maltase deficiency and the failure of the two disease forms to occur in the same family suggest that they are genetically distinct.

Acid maltase deficiency in adults presenting as respiratory failure.

During the past nine years 10 patients with the adult form of acid maltase deficiency have been observed at the Mayo Clinic. Three of the adults presented with respiratory failure. In all three the respiratory manifestations dominated the clinical picture and the cause of the respiratory failure (muscle weakness) and the underlying myopathy (glycogen storage disease) were initially unsuspected. Careful evaluation of the respiratory function tests, including the maximal static respiratory pressures, electromyographic examination and histochemical and biochemical studies of muscle biopsy specimens eventually led to the correct diagnosis.

Ultrastructure of the eye in fetal type II glycogenosis (Pompe's disease).

Type II glycogenosis is an autosomal recessive storage disease characterized by absence of the enzyme acid alpha-1,4-glucosidase. The eye of a 16 week fetus, aborted after diagnosis by amniocentesis, was studied by light and electron microscopy. Extensive deposits of lysosomal and cytoplasmic glycogen were present in virtually all ocular tissues examined, with the notable exception of pigment epithelia (iris and retina). The massive glycogen deposits present in this, the youngest case thus far examined histologically, emphasize the involvement of the fetus from its earliest stages and the importance of prenatal diagnosis.

Biochemical genetics of the Lapland dog model of glycogen storage disease type II (acid alpha-glucosidase deficiency).

A recently described canine model (Lapland dog) of glycogen storage disease type II (GSD II, Pompe disease, acid alpha-glucosidase deficiency) was identified with several biochemical genetic methods. Complementation studies in which fibroblasts from a GSD II dog were fused with fibroblasts derived from control dogs and from human patients with different clinical forms of the disease did not lead to restoration of acid alpha-glucosidase activity in the heterokaryon cell populations. These results indicate that acid alpha-glucosidase deficiency is the primary defect in canine GSD II and that there is a close genetic parallelism with human GSD II. Immunotitration analysis of the residual acid alpha-glucosidase activity in the canine GSD II fibroblasts and liver demonstrated that this residual activity was not due to acid alpha-glucosidase enzyme, in which respect canine GSD II was similar to the infantile form of the human disease. Double immunodiffusion studies showed the presence of catalytically inactive acid alpha-glucosidase enzyme protein in canine GSD II. This is consistent with a structural gene mutation. It is concluded that canine GSD II in the Lapland dog is a homologous model of the infantile form of human GSD II, a conclusion in concordance with clinical and pathological studies.

Metabolic myopathies.

Six glycogen storage diseases (resulting from deficiencies of acid maltase, phosphorylase, phosphofructokinase, phosphoglycerate kinase, phosphoglycerate mutase, and lactate dehydrogenase) and one mitochondrial myopathy (cytochrome c oxidase deficiency) are reviewed to illustrate: clinical heterogeneity, biochemical heterogeneity, evidence for tissue-specific and developmentally controlled isozymes, and molecular genetic studies.

Neutral oligosaccharides in the urine of a patient with glycogen storage disease type II.

Neutral oligosaccharides were isolated from urine of an adult patient with glycogen storage disease type II, a deficiency of lysosomal acid alpha-glucosidase, by chromatography on columns of activated charcoal, Dowex 50 X 2 and Dowex 1 X 2. Total neutral oligosaccharides in the urine of the patient were increased about 5-fold as compared with those in normal controls. The most accumulated oligosaccharide was separated by Bio-Gel P-2 column chromatography, and finally purified by paper chromatography. Based on various studies, including carbohydrate analysis, chemical ionization mass spectrometry, fast atom bombardment mass spectrometry, degradation by glucoamylase and isopullulanase, and methylation analysis, the structure of this oligosaccharide was deduced to be Glc alpha 1----6Glc alpha 1----4Glc alpha 1----4Glc. This oligosaccharide appears to be accumulated in urine of the patient with acid alpha-glucosidase deficiency as an end product of the hydrolysis of glycogen.

Acid maltase deficiency in non-identical adult twins. A morphological and biochemical study.

Acid maltase deficiency is described in non-identical adult twins. The onset of the disease can be traced into late infancy; the clinical picture is one of severe muscular dystrophy; respiratory insuficiency was the cause of death in one case. The autopsy showed the central nervous system, heart and liver to be spared. Glycogen filled vacuoles are found in skin, mesenchymal cells, small nerves and skeletal muscles. The light microscopic study of 9 different muscles showed extremely variable involvement ranging from normal appearance to overt vacuolization. A 6--20% residual acid alpha-glucosidase activity was found in visceral organs, cultured fibroblasts and in some skeletal muscles. No satisfactory explanation can be given why this generalized acid alpha-glucosidase deficiency produces a selective involvement of skeletal muscles. If compared with infantile AMD (Pompe's disease) our cases have a much higher residual acid alpha-glucosidase activity and show the presence of an antigenically detectable protein. From our study and from a similar report in the literature (de Barsy et al., 1975), it appears that a combined approach of light microscopy, electron microscopy and biochemical analysis (determination of acid alpha-glucosidase) is necessary to make a diagnosis of AMD in adults.