Identification of patients with Pompé disease using routine pathology results: PATHFINDER (creatine kinase) study.

AIMS: Adult-onset inherited errors of metabolism can be difficult to diagnose. Some cases of potentially treatable myopathy are caused by autosomal recessive acid α-1,4 glucosidase (acid maltase) deficiency (Pompé disease). This study investigated whether screening of asymptomatic patients with elevated creatine kinase (CK) could improve detection of Pompé disease. METHODS: Pathology databases in six hospitals were used to identify patients with elevated CK results (>2× upper limit of normal). Patients were recalled for measurement of acid α-1,4 glucosidase activity in dried blood spot samples. RESULTS: Samples were obtained from 812 patients with elevated CK. Low α-glucosidase activity was found in 13 patients (1.6%). Patients with neutropaenia (n=4) or who declined further testing (n=1) were excluded. Confirmation plasma specimens were obtained from eight individuals (1%) for a white cell lysosomal enzyme panel, and three (0.4%) were confirmed to have low α-1,4-glucosidase activity. One patient was identified as a heterozygous carrier of an acid α-1,4 glucosidase c.-32-13 G>T mutation. Screening also identified one patient who was found to have undiagnosed Fabry disease and one patient with McArdle's disease. One patient later presented with Pompé's after an acute illness. Including the latent case, the frequency of cases at 0.12% was lower than the 2.5% found in studies of patients with raised CK from neurology clinics (p<0.001). CONCLUSIONS: Screening pathology databases for elevated CK may identify patients with inherited metabolic errors affecting muscle metabolism. However, the frequency of Pompé's disease identified from laboratory populations was less than that in patients referred for neurological investigation.

Satellite cells fail to contribute to muscle repair but are functional in Pompe disease (glycogenosis type II).

Pompe disease, which is due to acid alpha-glucosidase deficiency, is characterized by skeletal muscle dysfunction attributed to the accumulation of glycogen-filled lysosomes and autophagic buildup. Despite the extensive tissue damages, a failure of satellite cell (SC) activation and lack of muscle regeneration have been reported in patients. However, the origin of this defective program is unknown. Additionally, whether these deficits occur gradually over the disease course is unclear. Using a longitudinal pathophysiological study of two muscles in a Pompe mouse model, here, we report that the enzymatic defect results in a premature saturating glycogen overload and a high number of enlarged lysosomes. The muscles gradually display profound remodeling as the number of autophagic vesicles, centronucleated fibers, and split fibers increases and larger fibers are lost. Only a few regenerated fibers were observed regardless of age, although the SC pool was preserved. Except for the early age, during which higher numbers of activated SCs and myoblasts were observed, no myogenic commitment was observed in response to the damage. Following in vivo injury, we established that muscle retains regenerative potential, demonstrating that the failure of SC participation in repair is related to an activation signal defect. Altogether, our findings provide new insight into the pathophysiology of Pompe disease and highlight that the activation signal defect of SCs compromises muscle repair, which could be related to the abnormal energetic supply following autophagic flux impairment.

α-Amylase, glucoamylase and isopullulanase determine molecular weight of pullulan produced by Aureobasidium melanogenum P16.

A high molecular weight (Mw) pullulan has many potential applications in various fields. α-Amylase, glucoamylase and pullulanase were thought to play an important role in high Mw pullulan biosynthesis. However, there is no genetic evidence for this role. In this study, the genes encoding α-amylase, glucoamylase and pullulanase were cloned from Aureobasidium melanogenum P16, a high pullulan producing yeast and characterized. The proteins deduced from the cloned α-amylase gene, the glucoamylase gene and the isopullulanase gene, not a pullululanse gene had their corresponding conserved amino acid sequences, respectively. After the single gene of them was deleted, the Mw of the pullulan produced by the single disruptants greatly increased and the pullulan concentration decreased. It was found that the triple mutant DT15 grown at the flask level could produce 46.2 g/L of pullulan with a Mw of 3.02 × 106 Da and grown in the 10-L fermentor could yield 58.14 g/L of pullulan with the same Mw while its wild type strain P16 produced 65.5 ±â€¯3.5 g/L of pullulan with a Mw of 0.35 × 106 Da. After the genes were complemented, pullulan production, Mw of the produced pullulan and others were restored. All the results demonstrated that the α-amylase, glucoamylase and isopullulanase indeed could determine the Mw of the produced pullulan.

Copackaged AAV9 Vectors Promote Simultaneous Immune Tolerance and Phenotypic Correction of Pompe Disease.

Pompe disease is a progressive neuromuscular disorder caused by lysosomal accumulation of glycogen from a deficiency in acid alpha-glucosidase (GAA). Replacement of the missing enzyme is available by repeated protein infusions; however, efficacy is limited by immune response and inability to restore enzymatic function in the central nervous system. An alternative therapeutic option is adeno-associated virus (AAV)-mediated gene therapy, which results in widespread gene transfer and prolonged transgene expression. Both enzyme replacement therapy (ERT) and gene therapy can elicit anti-GAA immune reactions that dampen their effectiveness and pose life-threatening risks to patient safety. To modulate the immune responses related to gene therapy, we show that a human codon-optimized GAA (coGAA) driven by a liver-specific promoter (LSP) using AAV9 is capable of promoting immune tolerance in a Gaa(-/-) mouse model. Copackaging AAV9-LSP-coGAA with the tissue-restricted desmin promoter (AAV9-DES-coGAA) demonstrates the necessary cell autonomous expression in cardiac muscle, skeletal muscle, peripheral nerve, and the spinal cord. Simultaneous high-level expression in liver led to the expansion of GAA-specific regulatory T-cells (Tregs) and induction of immune tolerance. Transfer of Tregs into naïve recipients prevented pathogenic allergic reactions after repeated ERT challenges. Copackaged AAV9 also attenuated preexisting humoral and cellular immune responses, which enhanced the biochemical correction. Our data present a therapeutic design in which simultaneous administration of two copackaged AAV constructs may provide therapeutic benefit and resolve immune reactions in the treatment of multisystem disorders.

[Variability in the clinical presentation of Pompe disease: development following enzyme replacement therapy]. / Variabilidad en la presentación clínica en la enfermedad de Pompe: evolución tras terapia de reemplazo enzimático.

INTRODUCTION: Pompe disease is a generalized progressive disease caused by a deficiency of the lysosome enzyme acid alpha-glucosidase (GAA). We present three cases with different clinical symptomatology and treated with enzyme replacement therapy (ERT) with positive evolution. CASE REPORTS: Case 1: three-month old male, with weakness and rejecting meals; mild hepatomegaly, discrete macroglossia and muscular hypotony; and increased muscular enzymes. Case 2: five-month old male, with delayed motor development, severe neurosensory deafness, and respiratory disorder of difficult evolution; muscular hypotony; and mild increase in creatine kinase. Case 3: 22-year old male, with progressive dyspnea, with history of increased creatine kinase and transaminases, and hypercholesterolemia. He suffered from severe respiratory failure requiring endotraqueal intubation Muscular biopsy showed glycogen storage suggestive of Pompe disease. In the three cases, the EMG showed a characteristic pattern with pseudomyotonic discharges and the deficiency in GAA was confirmed in lymphocytes. One single mutation was observed in one case and two in the other two cases. Every patient received ERT showing a favorable evolution; with disappearance of cardiac disorders in case 1, improvement in motor development in both infants and no longer need for mechanical ventilation in case 3. CONCLUSION: Pompe disease has a wide variability in clinical expression. ERT achieves a good response, especially in infant forms of the disease. The survival of treated patients with these Pompe disease forms will allow knowing further the course of the disease.

TITLE: Variabilidad en la presentacion clinica en la enfermedad de Pompe: evolucion tras terapia de reemplazo enzimatico.Introduccion. La enfermedad de Pompe es un trastorno generalizado progresivo producido por el deficit de la enzima alfa-glucosidasa acida (AGA) de los lisosomas. Se presentan tres casos manifestados de forma muy diferente y tratados con terapia enzimatica sustitutiva (TES), con evolucion favorable. Casos clinicos. Caso 1: varon de 3 meses, con debilidad y rechazo de la alimentacion, hepatomegalia leve, ligera macroglosia e hipotonia, y aumento de las enzimas musculares. Caso 2: varon de 5 meses, con retraso del desarrollo motor, sordera neurosensorial grave, trastornos respiratorios de repeticion de evolucion torpida, hipotonia y leve elevacion de la creatincinasa. Caso 3: varon de 22 años con disnea progresiva, con antecedentes de elevacion de la creatincinasa y las transaminasas, e hipercolesterolemia. Sufrio insuficiencia respiratoria grave que preciso intubacion endotraqueal. La biopsia muscular presento depositos de glucogeno sugestivos de la enfermedad. En los tres casos, el estudio electromiografico dio un patron caracteristico, con descargas pseudomiotonicas, y se confirmo el deficit de AGA en los linfocitos. Se encontro una mutacion en un caso y dos mutaciones en los otros dos. Todos recibieron TES con evolucion favorable: desaparicion de las alteraciones cardiacas en el caso 1, mejoria en los hitos motores en los dos casos infantiles y retirada del respirador en el caso 3. Conclusion. La enfermedad de Pompe tiene una amplia variabilidad en la expresion clinica. La TES consigue una buena respuesta, especialmente en las formas infantiles. La supervivencia a largo plazo de las formas infantiles tratadas permitira conocer mas aspectos del curso de la enfermedad.

[Guidelines for monitoring late-onset Pompe disease.Sociedad Española de Medicina Interna (SEMI), Sociedad Española de Neurología (SEN) y Sociedad Española de Neumología y CirugíaTorácica (SEPAR)]. / Guía para el seguimiento de la enfermedad de Pompe de inicio tardío.

Although treatment with alglucosidase alfa has helped improve the prognosis of patients with late-onset Pompe disease, both the development of the disease and the effectiveness of the treatment need to be monitored on a regular basis. This is the reason that has led a committee of Spanish experts to draw up a series of guidelines on how to follow up these patients. The committee proposes a model of follow-up tests for late-onset Pompe disease. First of all, the nutritional status and swallowing function must be evaluated. Second, and due to the variability of the clinical features, the committee recommends the simultaneous use of several scales to measure different functions and parameters. Thus, muscular force is assessed with the Medical Research Council scale; motor functioning, with the six-minute walk test and timed tests; disability, with the Rasch-built Pompe-specific Activity scale; respiratory functioning, with measurement of the forced vital capacity and oxygen saturation; and fatigue, with the fatigue intensity scale. Lastly, the safety and tolerability of enzyme replacement therapy are controlled by registering and treating the potential side effects and measurement of the anti-alglucosidase alfa antibodies. A number of different general recommendations are also included.

TITLE: Guia para el seguimiento de la enfermedad de Pompe de inicio tardio.Aunque el tratamiento con alglucosidasa alfa ha contribuido a mejorar el pronostico de los pacientes con enfermedad de Pompe de inicio tardio, es necesario hacer un seguimiento periodico de la evolucion de la enfermedad y de la eficacia del tratamiento. Por este motivo, un comite de expertos españoles ha elaborado una guia para el seguimiento de estos pacientes. El comite propone un modelo de pruebas de seguimiento para la enfermedad de Pompe de inicio tardio. En primer lugar, ha de valorarse el estado nutricional y la funcion deglutoria. En segundo lugar, y debido a la variabilidad del cuadro clinico, el comite recomienda el uso simultaneo de varias escalas que midan distintas funciones y parametros. De este modo, la fuerza muscular se evalua con la escala del Medical Research Council; la funcion motora, con la prueba de la marcha en seis minutos y pruebas cronometradas; la discapacidad, con la escala de actividad especifica de la enfermedad de Pompe construida segun el analisis de Rasch; la funcion respiratoria, con la medida de la capacidad vital forzada y la saturacion de oxigeno; y la fatiga, con la escala de intensidad de la fatiga. Por ultimo, la seguridad y la tolerabilidad del tratamiento enzimatico sustitutivo se controlan con el registro y tratamiento de los potenciales efectos adversos y la medicion de los anticuerpos antialglucosidasa alfa. Se incluyen tambien diversas recomendaciones generales.

Identification of the first deletion-insertion involving the complete structure of GAA gene and part of CCDC40 gene mediated by an Alu element.

Pompe disease is an uncommon autosomal recessive glycogen storage disorder caused by deficiency of acid α-glucosidase. Classic infantile form triggers severe cardiomyopathy, hypotonia, and respiratory failure, leading to death within the first two years of life. The majority of patients with Pompe disease have been reported to have point mutations in the GAA gene. We report the first complex deletion-insertion encompassing the complete structure of GAA gene and a large fragment of the gene CCDC40 in a patient with very severe form of Pompe disease. Sequencing analysis of breakpoints allowed us to determine the potential implication of an Alu repeat in the pathogenic mechanism. We suggest that molecular strategy of Pompe disease should include systematic analysis of large rearrangements.

Acid maltase deficiency--Pompe's disease.

Mutation in genes encoding for proteins involved in glycogen synthesis, degradation or regulation results in various inborn errors of glycogen metabolism. The disorders that result in abnormal storage of glycogen are known as glycogen storage diseases (GSD). We report a rare and interesting case of a young boy who presented with generalized weakness and reduced muscle bulk since childhood. He was diagnosed to have acid maltase deficiency, also known as Pompe's disease, one of the rare types of glycogen storage disease. The case is presented here in the form of a case study, including a review of the pertinent literature on the subject. This case has the potential to be the first reported case of such a disease from Pakistan (to the best of our knowledge).

Pompe disease: current state of treatment modalities and animal models.

Pompe disease is a rare autosomal recessive lysosomal storage disease caused by deficiency of acid-alpha-glucosidase (GAA). This deficiency results in glycogen accumulation in the lysosomes, leading to lysosomal swelling, cellular damage and organ dysfunction. In early-onset patients (the classical infantile form and juvenile form) this glycogen accumulation leads to death. The only therapy clinically available is enzyme replacement therapy, which compensates for the missing enzyme by i.v. administration of recombinant produced enzyme. The development of clinically relevant animal models gained more insight in the disease and allowed evaluation of recombinant enzyme therapy. Several therapies are currently under investigation for Pompe disease, including gene therapy. This review gives an overview of the available knockout mouse models, of the in vitro and in vivo studies performed using recombinant produced enzyme. Furthermore, it describes current therapeutic approaches for Pompe disease as well as experimental therapies like gene correction therapy.

Genotyping glycogen storage disease type II and type V in cattle reared in the Czech Republic.

Genotyping was carried out for glycogen storage disease type II and type V in seven cattle breeds. The analysis was carried out using the polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) method. In the breeds analysed [Charolais, Czech Spotted (Czech Simmental), Belgian Blue, Limousine, Blonde d'Aquitaine, Aberdeen Angus, and Beef Simmental sires reared in the Czech Republic], the recessive allele was not found in the PYGM (phosphorylase glycogen, muscle) responsible for the glycogen storage disease type V. In the same panel, the recessive allele in exon 7, exon 9 and exon 13 of the GAA (glucosidase alpha, acid), causing the glycogen storage disease type II was not found. Therefore, we have not revealed the recessives outside previous reported breeds. The knowledge of the breed-specific occurrence of inherited disorders facilitates focusing and reduces the costs of detecting the heterozygous carriers of recessive inherited disorders.

Isolated elevated serum transaminases leading to the diagnosis of asymptomatic Pompe disease.

An asymptomatic boy, aged 1.5 years, was referred with presumed liver disease because of persistently increased transaminase. Ultimately Pompe disease was confirmed, without specific abnormalities in muscle biopsy. This case demonstrates that increased transaminases do not always suggest liver disease. It is hard to determine prognosis and to decide whether enzyme replacement therapy should be started in asymptomatic patients with Pompe disease.

[Clinical and molecular genetic study on two patients of the juvenile form of Pompe disease in China].

OBJECTIVE: Glycogen-storage disease type II (GSD II, Pompe's disease) is an autosomal recessive disorder caused by a functional deficiency of acid alpha-glucosidase (GAA) that leads to glycogen accumulation within lysosomes in most tissues. The GAA gene is located to human chromosome 17q25 and contains 20 exons, 19 of which are coding. Clinically, patients with the severe infantile form of GSD II have muscle weakness and cardiomyopathy eventually leading to death before the age of two years. Patients with the juvenile or the adult form of GSD II present with myopathy with a slow progression over several years or decades. A broad genetic heterogeneity has been described in GSD II in Europe, South Africa, USA, Japan and Korea, however, the investigation has not been performed in the patients from the mainland of China. In this study, clinical analysis and mutation detection were done on Chinese patients. METHODS: Two unrelated juvenile patients with late onset GSD II (one boy, 3 years old and one girl, 9 years old) were included in the study with the informed consents. The diagnosis was confirmed by alpha-glucosidase determination in cultured fibroblasts. In addition, their clinical presentation, laboratory findings, electrophysiologic studies and muscle biopsy findings were analyzed in detail. Genomic DNA samples were extracted from fibroblasts of the probands, from peripheral blood of their parents and 50 unrelated, normal individuals. All the coding 19 exons and exon-intron boundaries of GAA were detected in the proband by polymerase chain reaction (PCR) and direct sequencing. RESULTS: One patient presented decrease of muscle strength, limb-girdle hypotonia, the other patient presented reduced muscle volumes and respiratory problems. Both had increased CPK value, myopathic pattern on EMG; vacuoles on muscle biopsy, and deficiency of 1, 4-alpha-glucosidase activity. After 1 year follow up, the girl died after pneumonia at 10 years of age. One patient was found to be compound heretozygote for the novel mutation Arg702His, and the previously reported mutation Pro266Ser, which was reported in Korean population, with the late-onset phenotype. Two novel missense mutations Thr711Arg, Val723Met were found on the other patients. CONCLUSIONS: Three mutations identified in the patient were new missense mutations causing late onset GSD II, which had not been reported elsewhere before.

[Myopathy associated with respiratory insufficiency: diagnostic difficulties in adult-onset Pompe disease]. / Légzészavarral járó myopathia: diagnosztikai nehézségek egy felnottkori Pompe-eset kapcsán.

INTRODUCTION: Adult-onset acid maltase deficiency myopathy is a rare lysosomal storage disease with an autosomal recessive pattern of inheritance. The disease can be manifested with respiratory insufficiency and fatigue. METHODS: A case of a 45-year-old male patient is presented, and difficulty in diagnosis is discussed. RESULTS: The patient had been repeatedly examined because of hypersomnia, dyspnea and fatigue for a full year before a neurological consultation was requested. Artificial ventilation resulted in a dramatic improvement of his symptoms. Neurological examination revealed myopathy. Electrophysiological myotonia and glycogen storage in muscle biopsy specimen suggested acid maltase deficiency. The diagnosis was established by genetic testing detecting the previously described homozygous c.-45T > G mutation in the alpha-glucosidase gene. DISCUSSION: Rare hereditary neurological diseases can be also suspected as cause of chronic unexplained respiratory insufficiency resulted in hypersomnia and fatigue due to hypercapnia and myopathy. A proper diagnosis can contribute to early diagnosis and introduction of enzyme replacement therapy may reduce or stop clinical progression. Genetic diagnosis can also provide a possibility for prenatal testing.

Pompe disease (glycogen storage disease type II): clinical features and enzyme replacement therapy.

Pompe disease (glycogen storage disease type II, acid maltase deficiency) is a progressive metabolic myopathy caused by deficiency of the lysosomal enzyme acid alpha-glucosidase. This leads to an accumulation of glycogen in various tissues of the body, most notably in skeletal muscle. The disease has an autosomal recessive inheritance with a predicted frequency of 1 :40.000. Pompe disease is a continuous spectrum but for clinical practice different subtypes are recognized. The classic infantile form of the disease occurs in infants (shortly after birth) and is characterized by generalized hypotonia, failure to thrive, and cardiorespiratory failure. Patients usually die within the first year of life. The non-classic or late-onset form of the disease may occur at any age in childhood or adulthood. It presents predominantly as a slowly progressive proximal myopathy, with or without respiratory failure. Enzyme replacement therapy (ERT) is under study as treatment for the disease. The first results with recombinant human alpha-glucosidase are promising and a registered therapy seems near. Beneficial effects of ERT have been reported both in patients with the classic infantile form as well as in patients with the non-classic or late-onset form of the disease. The best therapeutic results are achieved when ERT is started early in the course of symptom development and before irreversible muscular damage has occurred. Detailed knowledge about the natural course of the disease becomes more and more essential to determine the indication and timing of treatment.

Dysfunction of endocytic and autophagic pathways in a lysosomal storage disease.

OBJECTIVE: To understand the mechanisms of skeletal muscle destruction and resistance to enzyme replacement therapy in Pompe disease, a deficiency of lysosomal acid alpha-glucosidase (GAA), in which glycogen accumulates in lysosomes primarily in cardiac and skeletal muscles. METHODS: We have analyzed compartments of the lysosomal degradative pathway in GAA-deficient myoblasts and single type I and type II muscle fibers isolated from wild-type, untreated, and enzyme replacement therapy-treated GAA knock-out mice. RESULTS: Studies in myoblasts from GAA knock-out mice showed a dramatic expansion of vesicles of the endocytic/autophagic pathways, decreased vesicular movement in overcrowded cells, and an acidification defect in a subset of late endosomes/lysosomes. Analysis by confocal microscopy of isolated muscle fibers demonstrated that the consequences of the lysosomal glycogen accumulation are strikingly different in type I and II muscle fibers. Only type II fibers, which are the most resistant to therapy, contain large regions of autophagic buildup that span the entire length of the fibers. INTERPRETATION: The vastly increased autophagic buildup may be responsible for skeletal muscle damage and prevent efficient trafficking of replacement enzyme to lysosomes.

A new diagnostic assay for glycogen storage disease type II in mixed leukocytes.

We have established a new method for the enzymatic diagnosis of glycogen storage disease type II (Pompe disease or acid maltase deficiency) using mixed leukocytes. The method employs glycogen and 4-methylumbelliferyl-alpha-D-glucopyranoside (4MU-alphaGlc) as substrates for measuring the lysosomal acid alpha-glucosidase (acid alphaGlu) activity, and incorporates acarbose to eliminate the interference of unrelated alpha-glucosidases (predominantly maltase-glucoamylase). It is shown that 3.0 micromol/L acarbose completely inhibits the maltase-glucoamylase activity at pH 4.0, but the lysosomal acid alphaGlu activity by less than 5%. With this method, we determined the acid alphaGlu activity in mixed leukocytes from 25 patients with glycogen storage disease type II (2 infantile and 23 late-onset cases), one GAA2/GAA2 homozygote and 30 healthy subjects. In the assay with glycogen as substrate, the addition of acarbose created a clear separation between the patient and the control ranges. In the assay with 4MU-alphaGlc as substrate, the two ranges were fully separated but remained very close despite the use of acarbose. The separation of the patient and normal ranges was improved considerably by taking the ratio of acarbose-inhibited over uninhibited activity. A GAA2/GAA2 homozygote was correctly diagnosed with 4MU-alphaGlc but misdiagnosed as patient when glycogen was used as substrate. We conclude that the inclusion of 3.0 micromol/L acarbose in the assays with glycogen and 4MU-alphaGlc substrates at pH 4.0 allows for the specific measurement of lysosomal acid alphaGlu activity in mixed leukocytes, thus enabling a reliable diagnosis of glycogen storage disease type II in this specimen.