A novel missense mutation in the glycogen branching enzyme gene in a child with myopathy and hepatopathy.

We have identified a novel missense mutation in the gene for glycogen branching enzyme (GBE 1) in a 16-month-old infant with a combination of hepatic and muscular features, an atypical clinical presentation of glycogenosis type IV (GSD IV). The patient was heterozygous for a G-to-A substitution at codon 524 (R524Q), changing an encoded arginine (CGA) to glutamine (CAA), while the GBE1 gene on the other allele was not expressed. This case broadens the spectrum of mutations in patients with GSD IV and confirms the clinical and molecular heterogeneity of this disease.     

A case of congenital glycogen storage disease type IV with a novel GBE1 mutation

Glycogen storage disease type IV (Andersen disease) is a rare metabolic disorder characterized by deficient glycogen branching enzyme activity resulting in abnormal, amylopectin-like glycogen deposition in multiple organs. This article reports on an infant with the congenital neuromuscular subtype of glycogen storage disease type IV who presented with polyhydramnios, hydrops fetalis, bilateral ankle contractures, biventricular cardiac dysfunction, and severe facial and extremity weakness. A muscle biopsy showed the presence of material with histochemical and ultrastructural characteristics consistent with amylopectin. Biochemical analysis demonstrated severely reduced branching enzyme activity in muscle tissue and fibroblasts. Genetic analysis demonstrated a novel deletion of exon 16 within GBE1, the gene associated with glycogen storage disease type IV. Continued genetic characterization of glycogen storage disease type IV patients may aid in predicting clinical outcomes in these patients and may also help in identifying treatment strategies for this potentially devastating metabolic disorder.     

Whole exome sequencing in foetal akinesia expands the genotype–phenotype spectrum of GBE1 glycogen storage disease mutations

The clinically and genetically heterogenous foetal akinesias have low rates of genetic diagnosis. Exome sequencing of two siblings with phenotypic lethal multiple pterygium syndrome identified compound heterozygozity for a known splice site mutation (c.691+2T>C) and a novel missense mutation (c.956A>G; p.His319Arg) in glycogen branching enzyme 1 (GBE1). GBE1 mutations cause glycogen storage disease IV (GSD IV), including a severe foetal akinesia sub-phenotype. Re-investigating the muscle pathology identified storage material, consistent with GSD IV, which was confirmed biochemically. This study highlights the power of exome sequencing in genetically heterogeneous diseases and adds multiple pterygium syndrome to the phenotypic spectrum of GBE1 mutation.     

Branching enzyme deficiency/glycogenosis storage disease type IV presenting as a severe congenital hypotonia: Muscle biopsy and autopsy findings,biochemical and molecular genetic studies

The fatal infantile neuromuscular presentation of branching enzyme deficiency (glycogen storage disease type IV) due to mutations in the gene encoding the glycogen branching enzyme, is a rare but probably underdiagnosed cause of congenital hypotonia. We report an infant girl with severe generalized hypotonia, born at 33 weeks gestation who required ventilatory assistance since birth. She had bilateral ptosis, mild knee and foot contractures and echocardiographic evidence of cardiomyopathy. A muscle biopsy at 1 month of age showed typical polyglucosan storage. The autopsy at 3.5 months of age showed frontal cortex polymicrogyria and polyglucosan bodies in neurons of basal ganglia, thalamus, substantia innominata, brain stem, and myenteric plexus, as well as liver involvement. Glycogen branching enzyme activity in muscle was virtually undetectable. Sequencing of the GBE1 gene revealed a homozygous 28 base pair deletion and a single base insertion at the same site in exon 5. This case confirms previous observations that GBE deficiency ought to be included in the differential diagnosis of congenital hypotonia and that the phenotype correlates with the ‘molecular severity’ of the mutation.     

Adult polyglucosan body disease in Ashkenazi Jewish patients carrying the Tyr329 Ser mutation in the glycogen-branching enzyme gene

Adult polyglucosan body disease (APBD) is a late-onset, slowly progressive disorder of the nervous system caused by glycogen branching enzyme (GBE) deficiency in a subgroup of patients of Ashkenazi Jewish origin. Similar biochemical finding is shared by glycogen storage disease type IV (GSD IV) that, in contrast to APBD, is an early childhood disorder with primarily systemic manifestations. Recently, the GBE cDNA was cloned and several mutations were characterized in different clinical forms of GSD IV. To examine whether mutatins in the GBE gene account for APBD, we studied 7 patients from five Jewish families of Ashkenazi ancestry. The diagnosis was based on the typical clinical and pathological findings, and supported by reduced GBE activity. We found that the clinical and biochemical APBD phenotype in all five families cosegregated with the Tyr³²⁹Ser mutation, not detected in 140 controls. As this mutation was previously identified in a nonprogressive form of GSD IV and was shown in expression studies to result in a significant residual GBE activity, present findings explain the late onset and slowly progressive course of APBD in our patients. We conclude that APBD represents an allelic variant of GSD IV, but the reason for the difference in primary tissue involvement must be established.     

Association of the congenital neuromuscular form of glycogen storage disease type IV with a large deletion and recurrent frameshift mutation

Anderson disease, also known as glycogen storage disease type IV (MIM 232500), is a rare autosomal recessive disorder caused by a deficiency of glycogen branching enzyme. Glycogen storage disease type IV has a broad clinical spectrum ranging from a perinatal lethal form to a nonprogressive later-onset disease in adults. Here, we report 2 unrelated infants who were born small for their gestational age and who had profound hypotonia at birth and thus needed mechanical ventilation. Both of these patients shared the same frameshift mutation (c.288delA, pGly97GlufsX46) in the GBE1 gene. In addition, both of these patients were found to have 2 different large deletions in the GBE1 gene; exon 7 and exons 2 to 7, respectively, on the other alleles. This case report also highlights the need for a more comprehensive search for large deletion mutations associated with glycogen storage disease type IV, especially if routine GBE1 gene sequencing results are equivocal.     

Novel missense mutations in the glycogen-branching enzyme gene in adult polyglucosan body disease

We describe the first non-Ashkenazi patient with adult polyglucosan body disease and decreased glycogen-branching enzyme (GBE) activity in leukocytes. Gene analysis revealed compound heterozygosity for two novel missense mutations Arg515His and Arg524Gln in the GBE gene. Both missense mutations are predicted to impair GBE activity. This is the first identification of GBE mutations underlying adult polyglucosan body disease in a non-Ashkenazi family, and confirms that adult glycogen storage disease type IV can manifest clinically as adult polyglucosan body disease.     

Adult polyglucosan body disease: case description of an expanding genetic and clinical syndrome

A non-Jewish patient is described who had adult polyglucosan body disease (APBD) and glycogen branching enzyme (GBE) deficiency without GBE mutation. A heterozygous polymorphism (Val160Ile) was found, and also discovered in 1 of 50 normal individuals. Magnetic resonance imaging demonstrated increased T2 signal in the midbrain, medullary olives, dentate nuclei, cerebellar peduncles, and internal and external capsules, with vermian atrophy. Both muscle and nerve biopsy revealed perivascular inflammatory infiltrates. These findings expand the clinical and genetic spectrum of APBD. Factors other than mutation of the expressed GBE gene may cause enzyme deficiency and varied expression and development of APBD.     

Fatal infantile neuromuscular presentation of glycogen storage disease type IV

Glycogen storage disease type IV or Andersen disease is an autosomal recessive disorder due to deficiency of glycogen branching enzyme. Typically, glycogen storage disease type IV presents with rapidly progressive liver cirrhosis and death in childhood. Variants include a cardiopathic form of childhood, a relatively benign myopathic form of young adults, and a late-onset neurodegenerative disorder (adult polyglucosan body disease). A severe neuromuscular variant resembling Werdnig-Hoffmann disease has also been described in two patients. The objective was to describe two additional infants with the neuromuscular variant and novel mutations in the GBE1 gene. Branching enzyme assay, Western blot, RT-PCR and sequencing were performed in muscle biopsies from both patients. The cDNA of patient 1 was subcloned and sequenced to define the mutations. Muscle biopsies showed accumulation of periodic acid Schiff-positive, diastase-resistant storage material in both patients and increased lysosomal enzyme activity in patient 1. Branching enzyme activity in muscle was negligible in both patients, and Western blot showed decreased branching enzyme protein. Patient 1 had two single base pair deletions, one in exon 10 (1238delT) and the other in exon 12 (1467delC), and each parent was heterozygous for one of the deletions. Patient 2 had a large homozygous deletion that spanned 627 bp and included exons 8-12. Patient 1, who died at 41 days, had neurophysiological and neuropathological features of Spinal Muscular Atrophy. Patient 2, who died at 5(1/2) weeks, had a predominantly myopathic process. The infantile neuromuscular form of glycogen storage disease type IV is considered extremely rare, but our encountering two patients in close succession suggests that the disease may be underdiagnosed.     

Surprises of genetic engineering: a possible model of polyglucosan body disease.

BACKGROUND: The authors previously reported the generation of a knockout mouse model of Pompe disease caused by the inherited deficiency of lysosomal acid alpha-glucosidase (GAA). The disorder in the knockout mice (GAA-/-) resembles the human disease closely, except that the clinical symptoms develop late relative to the lifespan of the animals. In an attempt to accelerate the course of the disease in the knockouts, the authors increased the level of cytoplasmic glycogen by overexpressing glycogen synthase (GSase) or GlutI glucose transporter. METHODS: GAA-/- mice were crossed to transgenic mice overexpressing GSase or GlutI in skeletal muscle. RESULTS: Both transgenics on a GAA knockout background (GS/GAA-/- and GlutI/GAA-/-) developed a severe muscle wasting disorder with an early age at onset. This finding, however, is not the major focus of the study. Unexpectedly, the mice bearing the GSase transgene, but not those bearing the GlutI transgene, accumulated structurally abnormal polysaccharide (polyglucosan) similar to that observed in patients with Lafora disease, glycogenosis type IV, and glycogenosis type VII. Ultrastructurally, the periodic acid-Schiff (PAS)-positive polysaccharide inclusions were composed of short, amorphous, irregular branching filaments indistinguishable from classic polyglucosan bodies. The authors show here that increased level of GSase in the presence of normal glycogen branching enzyme (GBE) activity leads to polyglucosan accumulation. The authors have further shown that inactivation of lysosomal acid alpha-glucosidase in the knockout mice does not contribute to the process of polyglucosan formation. CONCLUSIONS: An imbalance between GSase and GBE activities is proposed as the mechanism involved in the production of polyglucosan bodies. The authors may have inadvertently created a "muscle polyglucosan disease" by simulating the mechanism for polyglucosan formation.     

Adult polyglucosan body disease: proton magnetic resonance spectroscopy of the brain and novel mutation in the GBE1 gene

Adult polyglucosan body disease (APBD) is characterized by the accumulation of insoluble glucose polymers within the central and peripheral nervous systems. A common missense mutation in the glycogen branching enzyme (GBE1) gene has been identified in Ashkenazi patients with APBD. We report on a non-Jewish patient with APBD on whom we performed proton magnetic resonance spectroscopic imaging of the brain. GBE activity in fibroblasts was markedly reduced, and a novel heterozygous mutation was identified in the GBE1 gene. Our findings widen the spectrum of APBD genotypes, underline the importance of performing GBE analysis in all APBD patients, and suggest that brain white matter degeneration in APBD may result from tissue damage involving axons and myelin.     

Myopathies Related to Glycogen Metabolism Disorders

Most of the glycogen metabolism disorders that affect skeletal muscle involve enzymes in glycogenolysis (myophosphorylase (PYGM), glycogen debranching enzyme (AGL), phosphorylase b kinase (PHKB)) and glycolysis (phosphofructokinase (PFK), phosphoglycerate mutase (PGAM2), aldolase A (ALDOA), β-enolase (ENO3)); however, 3 involve glycogen synthesis (glycogenin-1 (GYG1), glycogen synthase (GSE), and branching enzyme (GBE1)). Many present with exercise-induced cramps and rhabdomyolysis with higher-intensity exercise (i.e., PYGM, PFK, PGAM2), yet others present with muscle atrophy and weakness (GYG1, AGL, GBE1). A failure of serum lactate to rise with exercise with an exaggerated ammonia response is a common, but not invariant, finding. The serum creatine kinase (CK) is often elevated in the myopathic forms and in PYGM deficiency, but can be normal and increase only with rhabdomyolysis (PGAM2, PFK, ENO3). Therapy for glycogen storage diseases that result in exercise-induced symptoms includes lifestyle adaptation and carefully titrated exercise. Immediate pre-exercise carbohydrate improves symptoms in the glycogenolytic defects (i.e., PYGM), but can exacerbate symptoms in glycolytic defects (i.e., PFK). Creatine monohydrate in low dose may provide a mild benefit in PYGM mutations.     

Muscle power development in preterm infants with periventricular flaring or leukomalacia in relation to outcome at 18 months

Periventricular flaring (PVF) or periventricular leukomalacia (PVL) was diagnosed by brain ultrasound during the neonatal period in 44 infants (34 males, 10 females; mean gestational age 31 weeks 2 days, SD 2 weeks 1 day) admitted between 1995 and 1997. The infants were divided into three groups according to the severity of their condition. At 0, 3, and 6 months' corrected age an age-adequate neurological examination with special emphasis on the relation between active and passive muscle power was performed and symmetry between right and left sides was assessed. Results for the whole body, as well as for the shoulders, trunk, and legs were classified as optimal, suspect, or abnormal. Motor outcome at 18 months' corrected age was graded in the same way. An overall optimal muscle power regulation was found in one infant at 0, two at 3, and one at 6 months. Suspect outcome was found at all ages in the three groups. At 0 months muscle power regulation did not differ between the three groups. At 3 and 6 months overall poor muscle power, primarily caused by poor muscle power regulation in the shoulders and trunk, was found in infants with PVL grades III or IV. At 18 months' corrected age 24 infants showed no neurological impairment, eight infants had minor impairment, and 12 infants had severe impairment, including all 10 infants categorized as having PVL grades II or IV. The best predictors of impairment at 18 months were the combined results of muscle power in the shoulders and trunk at 3 months with those of the shoulders at 6 months.     

一氧化氮与蛛网膜下腔出血后缺血性脑损害关系和银杏叶制剂的保护作用

目的探讨一氧化氮（ＮＯ）与蛛网膜下腔出血（ＳＡＨ）后缺血性脑损害的关系和银杏叶制剂（ＧＢＥ）的保护作用。方法应用非开颅大鼠模型，对ＳＡＨ组和ＧＢＥ组测量基底动脉（ＢＡ）管径并观察２４ｈ内微区脑血流量（ＣＢＦ）和颅内血清ＮＯ水平动态改变，３ｄ后对海马ＣＡ１区行病理检查。结果ＳＡＨ后ＣＢＦ和血清ＮＯ降低，ＢＡ痉挛，海马ＣＡ１区神经元明显受损。ＧＢＥ使上述改变减轻。结论ＳＡＨ时血清ＮＯ减少是导致缺血性脑损害的重要因素，ＧＢＥ通过影响ＮＯ病理性改变而减轻缺血性脑损害     

银杏叶提取物对锂-匹罗卡品癫痫大鼠海马结构c-Fos蛋白表达的影响

目的:研究银杏叶提取物(GBE)对癫痫的干预作用及其对癫痫大鼠海马结构c-Fos蛋白表达的影响。方 法:采用锂-匹罗卡品癫痫(LPS)大鼠模型。观察动物行为改变,应用免疫组化方法观察海马结构c-Fos蛋白的表达。结 果:GBE对该模型癫痫发作的预防有效率和治疗有效率分别为94．44％和35．48％。与LPS组相比,GBE预处理组的4 级以上发作率和发作分级明显下降;站立发作潜伏期延长。注射匹罗卡品后3小时,生理盐水对照组、GBE单独给药组 和GBE预处理组大鼠海马结构c-Fos蛋白表达阴性。LPS组和GBE急性给药组大鼠海马结构c-Fos蛋白表达阳性。 结论:GBE预处理和急性给药两种给药模式均有一定的抗LPS作用,前者明显优于后者。GBE抗LPS作用的机制可能 与GBE能抑制海马结构c-Fos蛋白表达有关。     

银杏叶提取物对脑缺血大鼠脑源性神经营养因子的影响

目的　观察银杏叶提取物 (GBE)对局灶脑缺血大鼠脑源性神经营养因子 (BDNF)表达的影响 ,探讨GBE与缺血损伤神经元可塑性的关系。方法　制作大鼠大脑中动脉闭塞 (MCAO)模型 ,应用免疫组化方法观察不同缺血时间 GBE治疗组及脑缺血组 BDNF阳性细胞数 ,并进行图像分析。结果　坏死灶中心区 GBE组及缺血组BDNF阳性神经元均消失 ,但在坏死灶周围区 ,两组 BDNF阳性细胞均显著增加。两组细胞形态无明显不同 ,但GBE治疗组阳性细胞数又显著高于相应缺血对照组。结论　银杏叶提取物可提高大鼠局灶脑缺血半暗带区 BDNF的表达水平 ,促进神经元的修复及重塑。     

Ginkgo biloba extract improves spatial memory in rats mainly but not exclusively via a histaminergic mechanism

In order to clarify the mechanism of Ginkgo biloba extract (GBE) on learning and memory, we studied the effect of GBE on spatial memory deficits induced by diphenhydramine, pyrilamine and scopolamine using the eight-arm radial maze performance of rats, in comparison with donepezil. Total error (TE), reference memory error (RME) and working memory error (WME) were used as indices of spatial memory deficits. Both GBE and donepezil caused a potent antagonistic effect on the increase in TE, RME and WME induced by diphenhydramine. GBE and donepezil also antagonized scopolamine-induced spatial memory deficits. Although the antagonistic effect of GBE on pyrilamine-induced spatial memory deficits was weak, a significant difference was observed with TE and WME. However, donepezil caused no antagonistic effect on pyrilamine-induced memory deficits. From these findings, we concluded that the effects of GBE are mainly contributable to cholinergic activity and perhaps partly due to a histaminergic mechanism.     

Congenital type IV glycogenosis: the spectrum of pleomorphic polyglucosan bodies in muscle, nerve, and spinal cord with two novel mutations in the GBE1 gene

A diagnosis of GSD-IV was established in three premature, floppy infants based on characteristic, however unusually pleomorphic polyglucosan bodies at the electron microscopic level, glycogen branching enzyme deficiency in two cases, and the identification of GBE1 mutations in two cases. Pleomorphic polyglucosan bodies in muscle fibers and macrophages, and less severe in Schwann cells and microglial cells were noted. Most of the inclusions were granular and membrane-bound; others had an irregular contour, were more electron dense and were not membrane bound, or homogenous (‘hyaline’). A paracrystalline pattern of granules was repeatedly noted showing a periodicity of about 10 nm with an angle of about 60° or 120° at sites of changing linear orientation. Malteser crosses were noted under polarized light in the larger inclusions. Some inclusions were PAS positive and others were not. Severely atrophic muscle fibers without inclusions, but with depletion of myofibrils in the plane of section studied indicated the devastating myopathic nature of the disease. Schwann cells and peripheral axons were less severely affected as was the spinal cord. Two novel protein-truncating mutations (c.1077insT, p.V359fsX16; g.101517_127067del25550insCAGTACTAA, DelExon4-7) were identified in these families. The present findings extend previous studies indicating that truncating GBE1 mutations cause a spectrum of severe diseases ranging from generalized intrauterine hydrops to fatal perinatal hypotonia and fatal cardiomyopathy in the first months of life. Kay W. Nolte and Andreas R. Janecke contributed equally to this study.     

银杏叶提取物GBE50对实验性衰老大鼠海马CA1 区突触可塑性及学习记忆功能的影响

The content of total flavonoids in an extract of Ginkgo biloba,called GBE50,is 44% by weight.This is significantly greater than that in a standard extract of Ginkgo biloba,designated EGB761.To date,the mechanisms by which GBE50 and EGB761 function remain poorly understood.In the present study,an experimental rat model of aging was induced by intraperitoneal injection of D-galactose,followed by intragastric perfusion of GBE50 (30,60mg/kg),or EGB761 (60mg/kg).The water maze scores and hippocampal CA1 synaptic plasticity were evaluated.In the place navigation test,the GBE50 group rats did better than EGB761,while similar scores were obtained in the spatial probe test,and in the platform-switched test.In addition,long-term potentiation was significantly enhanced following high-frequency stimulation in the GBE50 and EGB761 groups,compared with the model group.These results demonstrate that GBE50 and EGB761 improved the learning and memory of aging rats.In particular,GBE50 administered at the 60mg/kg dose exhibited superior effects over EGB761 at the same 60mg/kg dose.Furthermore,the enhancement of hippocampal synaptic plasticity may be an underlying mechanism.