Is it Pompe Disease? Australian diagnostic considerations.

Pompe Disease is a spectrum disorder with an evolving phenotype in which diagnostic delay is common. Contributing factors include the rarity of the disorder, its wide clinical spectrum, signs and symptoms that overlap with those of other neuromuscular disorders, variable diagnostic approaches, lack of awareness of the clinical manifestations and difficulties in completing the diagnostic inventory. International updates and recommendations have been published providing diagnostic guidelines and management criteria. However, questions remain in the Australian setting. A panel (two neurologists, one clinical geneticist) reviewed the literature, examined clinical questions of relevance to the Australian setting, and developed a framework for the guidance. A wider panel, comprising the initial panel plus eight additional members, critiqued the framework and contributed clinical guidance within the scope of their respective areas of clinical expertise. The resultant expert consensus recommendations build on currently available data to propose an appropriate management framework incorporating the diagnosis, classification, therapeutic approach, multidisciplinary care, and on-going monitoring of patients with Pompe Disease in the Australian setting. It is hoped that diagnostic delay can be reduced with appropriate recourse to evidence-based insights and practical advice on diagnosis and management tailored to the Australian setting.

[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.

Diagnosis and management of Pompe disease.

Pompe disease (PD) is an autosomal-recessively inherited neuromuscular disease that, if not diagnosed and treated early, can be fatal. It can present from early infancy into adulthood. Due to the lack of acid alpha-glucosidase, there is progressive intracellular accumulation of glycogen. The severity of the disease is determined by age of onset, organ involvement including the degree of severity of muscle involvement, as well as rate of progression. PD is classified into two groups: infantile and late-onset, each having two subgroups. The need for two tests performed by separate methods (screening and confirmatory) is outlined. It is imperative to try to reduce the time to diagnosis and to recognise the possibilities of false-positive results. A multidisciplinary team approach to treatment of affected patients is optimum with, as team leader, a physician who has experience in managing this rare disorder. In this article, we present a brief overview of the disease and provide guidelines for diagnosis and management of this condition in South Africa.

Trunk muscle involvement in late-onset Pompe disease: study of thirty patients.

Late-onset Pompe disease is characterized by progressive weakness involving proximal limb and respiratory muscles. Recently, treatment with enzyme replacement therapy (ERT) has been introduced partially improving patients' prognosis, but a standard consensus on when to start ERT is still lacking. There is also a lack of biomarkers related to the clinical progression of the disease. Here we used muscle magnetic resonance imaging (MRI) or computed tomography (CT) to study the abdominal and paravertebral muscles of 30 late-onset Pompe patients at different stages of disease. We observed a selective pattern of muscle damage, with early involvement of the Multifidus muscle, followed by the Obliquus internus abdominis and Longissimus muscle. Some degree of trunk involvement on MRI occurred even in asymptomatic patients. Severity of muscle involvement in MRI correlated with patients' functional stage. We suggest that: (a) the combination of paravertebral and abdominal muscle involvement may serve as a useful tool in the diagnostic work-up of patients with a clinical suspicion of Pompe disease; (b) trunk abnormalities appear at very early stages of disease and even in asymptomatic patients, possibly "announcing" the onset of the disease and thus the need for a closer clinical follow-up.

[Metabolic myopathies - an overview]. / Metabolische Myopathien - ein Uberblick.

Metabolic disorders of energy production characterise the group of rare, mainly autosomal recessively inherited metabolic muscular diseases which are often associated with multi-systemic symptoms. In this report, an update on the clinics, pathophysiology, pathomorphology and current treatment options of metabolic myopathies will be given. Beyond classic phenotypes of these disorders, one should be aware of oligosymptomatic patients who can be easily missed. The relevant gene mutations and the pathophysiology and pathomorphology they cause are now known for almost all these metabolic diseases. Establishing the correct diagnosis has become even more important since highly specific therapy options are now available for at least some of these inherited disorders, e.g. enzyme replacement therapy in Pompe disease.

The natural course of non-classic Pompe's disease; a review of 225 published cases.

Pompe's disease is a neuromuscular disorder caused by deficiency of lysosomal acid alpha-glucosidase. Recombinant human alpha- glucosidase is under evaluation as therapeutic drug. In light of this development we studied the natural course of cases not fitting the definition of classic infantile Pompe's disease. Our review of 109 reports including 225 cases shows a continuous spectrum of phenotypes. The onset of symptoms ranged from 0 to 71 years. Based on the available literature, no criteria to delineate clinical sub-types could be established.A common denominator of these cases is that first symptoms were related to or caused by muscle weakness. In general, patients with a later onset of symptoms seemed to have a better prognosis. Respiratory failure was the most frequent cause of death. CK, LDH, ASAT, ALAT and muscle glycogen levels were frequently but not always elevated. In most cases a muscle biopsy revealed lysosomal pathology, but normal muscle morphology does not exclude Pompe's disease. In 10% of the cases in which the enzyme assay on leukocytes was used, a normal alpha-glucosidase activity was reported. Data on skeletal muscle strength and function, pulmonary function, disability, handicap and quality of life were insufficiently reported in the literature. Studies of non-classic Pompe's disease should focus on these aspects, before enzyme replacement therapy becomes generally available.

Identification of two subtypes of infantile acid maltase deficiency.

Infantile patients with acid maltase deficiency have severe hypertrophic cardiomyopathy, left ventricular outflow obstruction, and generalized muscle weakness and die before 1 year of age. We identified 12 infants with acid maltase deficiency who had a similar clinical presentation but less severe cardiomyopathy and absence of left ventricular outflow obstruction, and 9 of 12 had longer survival with assisted ventilation and supplemental intubation.

Late infantile acid maltase deficiency: a case report.

A five-year-old boy with late-infantile (juvenile) form of acid maltase deficiency is presented. His symptoms were restricted to skeletal muscle. There is commonly a correlation between the amount of residual acid maltase activity and the severity of the clinical picture. Although the residual enzyme level was very low in our patient, no progression of his neurological findings have been observed during the follow-up period of two years.

[Pompe's disease--acid alpha-glucosidase deficiency--a review].

The importance of the role of acid alpha-glucosidase in the lysosomal degradation of glycogen has been emphasized because the deficiency of this enzyme in glycogenosis type II causes glycogen accumulation in lysosomes. Three clinical variants are distinguished. The infantile type has its onset shortly after birth and is known as generalized glycogen storage disease. The adult variant manifests itself mostly after the second decade of life and is characterized by progressive skeletal muscle weakness. The other is childhood type which is usually fatal by the second decade of life. Many biochemical reports of acid alpha-glucosidase have been published. Martiniuk et al reported the cDNA and amino acid sequence of human acid alpha-glucosidase. In prior studies, they reported that the lysosomal acid alpha-glucosidase was polymorphic with three alleles. The rarer allele GAA2 allozyme had a lower affinity for glycogen and starch. We also reported the enzyme heterogeneity in its affinity to Sephacryl S-200 gel. Whereby the enzyme separated into two fractions, S1 and S2. Each fraction contained 76 kDa and 67 kDa components on SDS/PAGE. The spleen enzyme consisted mainly of S1 fraction, containing only a 76 kDa component. In previous extensive studies, different mutations of Pompe's disease have been inferred from alterations in biochemical parameters. More recently Martiniuk et al, Hoefsloot et al and Van der Ploeg et al reported the analysis of cDNA and mRNA. These studies have revealed an absence or abnormal size of mRNA in large numbers of patients and altered restriction endonuclease fragments in a few patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnóstico clínico-bioquímico de la enfermedad de Pompe

La enfermedad de Pompe es una de las glicogenosis o enferemdad de depósito del glucógeno, que se transmite con carácter autosómico recesivo y es producida por la deficiencia de la enzima maltasa ácida que degrada glicógeno en los lisosomas. Se dintinguen tres tipos de enferemdad de Pompe : el tipo infantil que se acracteriza por la acumulación de glicógeno en el hígado, músculo esquelético y cardíaco y células del sistema nervioso central; los pacientes fallecen usaulamente antes de los dos años por falla cardiorespiratoria; el fenotipo juvenil se presenta en niños o jóvenes, no siempre involucra el sistema nervioso central o el músculo cardíaco y los pacientes fallecen generalmente durante la segunda década de vida; el tipo adulto cursa con distrofia muscular, algunas veces asociada con deficiencia respiratoria por compromiso de los músculos diagragma e intercostales. El pronóstico depende del grado de la falla respiratoria, la cual es causa principal de la muerte de estos pacientes. En este trabajo se informa el caso de un niño de seis meses de edad, afectado por cardiomegalia, retardo psicomotor e hipotonía. La confirmación bioquímica de la enfermedad se hizo determinando la actividad de la alfa-glucosidasa en leucocitos por dos métodos diferentes, usando como sustrato maltasa o el sustrato fluorescente 4-metil-umbeliferil-glucósido. La actividad de la maltasa ácida en leucocitos, usando maltosa como sustrato fue de 6,36Umol glucosa/min/g, con un valor de referencia entre 16-63 Umoles/glucosa/min/g de proteína. Con el sustrato fluorogénico, la activida en el paciente fue de 34.48 nanomoles/h/mg, de proteína, para un valor de referencia entre 194 y 258. La actividad en leucocitos tanto del padre como de la madre corresponde a un 60 por ciento del valor normal, hallado en personas en cuya familia no se sospecha dicha enfermedad.

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.