RESUMO
INTRODUCTION: Mucopolysaccharidosis (MPS) IIIB is a lysosomal disorder in which a deficiency in α-N-acetylglucosaminidase impairs the degradation of heparan sulphate, which accumulates in tissues causing multiple organs dysfunction. This disease is associated with significant central nervous system (CNS) abnormalities, but a presentation with a tumour-like lesion has never been reported so far. CLINICAL PRESENTATION: The present report describes the case of a 5-year-old girl suffering from MPS IIIB who developed a cerebellar lesion with evident mass effect. She underwent surgery with a subsequent notable improvement of her clinical picture. Surprisingly, the pathological analysis revealed the lesion to have the typical MPS features. CONCLUSION: This case would describe a neglected possible presentation of MPS IIIB with a lesion mimicking a neoplasm, which could even be successfully treated with surgery.
Assuntos
Neoplasias Cerebelares , Mucopolissacaridoses , Mucopolissacaridose III , Neoplasias Cerebelares/diagnóstico por imagem , Neoplasias Cerebelares/cirurgia , Pré-Escolar , Feminino , Glicosaminoglicanos , Humanos , Lisossomos , Mucopolissacaridose III/diagnóstico por imagemRESUMO
OBJECTIVE: Organic acidurias (OAs) are a group of rare metabolic disorders that disrupt the regular amino acid metabolism. OAs are characterized by recurrent episodes of acidemia, ketonuria and hyperammonemia which can result in brain/liver damage and renal failure, and despite the life-long protein-restricted diet, impaired growth and long-term complications can occur. Consequently, a long-term management of OAs patients is required, aimed principally at reducing the frequency and duration of metabolic decompensation/hyperammonemia episodes. Nevertheless, unlike the acute phase, evidence on the chronic management of OAs patients is less consolidated. SUBJECTS AND METHODS: To expand the knowledge on this field, 13 Italian referral centers for the management of OAs were involved in a survey focused on the long-term use of carglumic acid (Carbaglu®, Recordati Rare Diseases). RESULTS: Participating centers reported a reduction between 69% and 81% in the annual number of metabolic decompensations with the chronic use of carglumic acid and an improvement in protein intake. Most centers reported no difficulty using carglumic acid as a long-term therapy, along with a great compliance. CONCLUSIONS: Taken together, obtained data align with the available literature and support a positive clinical experience with the long-term carglumic acid administration. Additional studies aimed at better defining a proper dosage for the chronic administration of carglumic acid and the clinical and biochemical characteristics of patients treated chronically are needed. In addition, the potential impact of this treatment regimen on the neurological development and growth of patients should be elucidated.
Assuntos
Hiperamonemia , Acidemia Propiônica , Erros Inatos do Metabolismo dos Aminoácidos , Glutamatos/uso terapêutico , Humanos , Acidemia Propiônica/tratamento farmacológicoRESUMO
Hemolytic uremic syndrome (HUS) is characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure. Besides diarrhea-associated HUS, due to verotoxin-producing Escherichia coli, in children HUS without prodromal diarrhea may be associated with other infectious and autoimmune diseases, genetic defects of the complement-regulator alternative-pathway, and inborn errors of vitamin B12 metabolism. Rhabdomyolysis is the dissolution of skeletal muscle due to various causes, including inborn errors of metabolism. Recurrent rhabdomyolysis and HUS have been previously described in one patient with a genetic defect of oxidative phosphorylation. We report the case of a 2-year-old boy with recurrent HUS and rhabdomyolysis in whom a succinate coenzyme Q reductase (complex II) deficiency was diagnosed. We hypothesize that defects of oxidative phosphorylation could be another etiological factor in atypical HUS.
Assuntos
Complexo II de Transporte de Elétrons/deficiência , Síndrome Hemolítico-Urêmica/etiologia , Rabdomiólise/etiologia , Pré-Escolar , Síndrome Hemolítico-Urêmica/diagnóstico , Síndrome Hemolítico-Urêmica/enzimologia , Humanos , Masculino , Doenças Mitocondriais/diagnóstico , Doenças Mitocondriais/metabolismo , Doenças Mitocondriais/patologia , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Rabdomiólise/diagnóstico , Rabdomiólise/enzimologia , Rabdomiólise/patologiaRESUMO
Polymorphonuclear leukocytes (PMN) have been identified as cells capable of producing a number of pro- and antiinflammatory cytokines in response to specific agonists. Previously, we showed that tumor necrosis factor (TNF), interleukin-1 beta (IL-1 beta), and IL-8, are produced by PMN after stimulation with agonists, such as lipopolysaccharide (LPS). In this study, we demonstrate that LPS is also a potent stimulus for the mRNA expression and release of the IL-1 receptor antagonist (IL-1ra). In addition, we show that the release of IL-1ra from LPS-stimulated PMN is markedly potentiated in the presence of IL-10 (from two to threefold after 18 h of stimulation). Moreover, we observed that this upregulation of IL-1ra production by IL-10 in LPS-stimulated PMN took place through IL-1ra mRNA stabilization. Indeed, the half-life of IL-1ra mRNA was prolonged in PMN stimulated in the presence of IL-10 and LPS, as compared with cells stimulated with LPS alone. That IL-10 selectively upregulates IL-1ra production in LPS-activated PMN, while it inhibits the production of IL-1 beta, TNF, and IL-8 under the same conditions, suggests that IL-10 may be an important physiologic regulator of cytokine production from PMN, and emphasizes the potential role of IL-10 in inflammatory responses.
Assuntos
Interleucina-10/metabolismo , Lipopolissacarídeos/farmacologia , Neutrófilos/metabolismo , Receptores de Interleucina-1/antagonistas & inibidores , Sialoglicoproteínas/biossíntese , Células Cultivadas , Humanos , Proteína Antagonista do Receptor de Interleucina 1 , Neutrófilos/efeitos dos fármacos , Neutrófilos/imunologia , RNA Mensageiro/metabolismo , Regulação para CimaRESUMO
AIMS: To isolate and characterize an anaerobic bacterial strain from the deeper polluted lagoon sediment able to use as electron acceptors [As(V)] and sulfate (SO4(2-)), using lactate as an electron donor. METHODS AND RESULTS: Methods for isolation from polluted lagoon sediments included anaerobic enrichment cultures in the presence of As(V) and SO4(2-). Reduction of As(V) to As(III) was observed during the growth of the bacterial strain, and the final concentration of As(III) was lower than the initial As(V) one, suggesting the immobilization of As(III) in the yellow precipitate. The precipitate was identified by energy dispersive spectroscopy X-ray as arsenic sulfide. Scanning electron microscopy (SEM) revealed rod-shaped bacterial cells embedded in the precipitate, where net-like formations strictly related to the bacterial cells were visible. The surface of the precipitate showed the adhesion of bacterial cells, forming clusters. Transmission electron microscopy (TEM) also highlighted precipitates inside the bacterial cells and on their surface. Following 16S rRNA sequencing, the bacterial strain 063 was assigned to the genus Desulfosporosinus. CONCLUSIONS: This study reports, for the first time, the isolation from the polluted lagoon sediments of a strain capable of respiring and using As(V) and SO4(2-) as electron acceptors with lactate as the sole carbon and energy source with the formation of an arsenic sulfide precipitate. SIGNIFICANCE AND IMPACT OF THE STUDY: The identification of these properties provides novel insight into the possible use of the anaerobic strain in bioremediation processes and also adds to the knowledge on the biogeochemical cycling of arsenic.
Assuntos
Arsênio/metabolismo , Arsenicais/metabolismo , Sedimentos Geológicos/microbiologia , Peptococcaceae/isolamento & purificação , Peptococcaceae/metabolismo , Poluentes do Solo/metabolismo , Sulfetos/metabolismo , Anaerobiose , Biodegradação Ambiental , DNA Bacteriano/genética , Itália , Dados de Sequência Molecular , Peptococcaceae/classificação , Peptococcaceae/genética , Filogenia , RNA Ribossômico 16S/genéticaRESUMO
BACKGROUND: The treatment with recombinant human growth hormone in patients affected by Mucopolysaccharidoses (MPS) is considered whenever a concurrent diagnosis of growth hormone deficiency is demonstrated. The short- and long-term effects of recombinant human growth hormone in this selected cohort is still debated, given the natural progression of disease-related skeletal malformations and the paucity of treated patients reported in literature. The presented case series provides detailed information about the response to recombinant growth hormone in MPS patients diagnosed with growth hormone deficiency. CASES PRESENTATION: The growth patterns of 4 MPS female patients (current age: 11.7-14.3 years) treated with recombinant human growth hormone due to growth hormone deficiency have been retrospectively analyzed. Two patients, diagnosed with MPS IH, had undergone haematopoietic stem cell transplantation at an early age; the remaining two patients were affected by MPS IV and VI and were treated with enzyme replacement therapy. 4/4 patients presented with a progressive growth deceleration before the diagnosis of growth hormone deficiency was confirmed. This trend was initially reverted by a remarkable increase in height velocity after the start of recombinant growth hormone. We recorded an average increase in height velocity z-score of + 4.23 ± 2.9 and + 4.55 ± 0.96 respectively after 6 and 12 months of treatment. After the first 12-24 months, growth showed a deceleration in all the patients. While in a girl with MPS IH recombinant human growth hormone was discontinued due to a lack in clinical efficacy, 3/4 patients grew at a stable pace, tracking the height centile achieved after the cited initial increase in height velocity. Furthermore, mineral bone density assessed via bone densitometry, showed a remarkable increase in the two patients who were tested before and after starting treatment. CONCLUSIONS: Recombinant human growth hormone appears to have effectively reverted the growth deceleration experienced by MPS patients diagnosed with growth hormone deficiency, at least during the first 12-24 months of treatment.
Assuntos
Hormônio do Crescimento Humano/uso terapêutico , Mucopolissacaridoses/tratamento farmacológico , Adolescente , Densidade Óssea/efeitos dos fármacos , Criança , Terapia de Reposição de Enzimas , Feminino , Transplante de Células-Tronco Hematopoéticas , Hormônio do Crescimento Humano/deficiência , Humanos , Estudos RetrospectivosRESUMO
The patients affected by vitamin B12-unresponsive methylmalonic acidemia (MMA) on the long run develop chronic renal disease with interstitial nephropathy and progressive renal insufficiency. The mechanism of nephrotoxicity in vitamin B12-unresponsive MMA is not yet known. Chronic hyporeninemic hypoaldosteronism has been found in many cases of methylmalonic acidemia, hyperkalemia and renal tubular acidosis type 4. We report 2 patients affected by B12-unresponsive methylmalonic acidemia diagnosed at the age of 23 months and 5 years, respectively, with normal glomerular filtration and function. They showed hyporeninemic hypoaldosteronism and significant hyperkalemia requiring sodium potassium exchange resin (Kayexalate) therapy after an episode of metabolic decompensation leading to diagnosis of MMA. In both children, hyporeninemic hypoaldosteronism and hyperkalemia disappeared after 6 months of good metabolic control.
Assuntos
Fumaratos/sangue , Hiperpotassemia/etiologia , Maleatos/sangue , Pré-Escolar , Feminino , Humanos , Hiperpotassemia/fisiopatologia , Hiperpotassemia/terapia , Hipoaldosteronismo/etiologia , Hipoaldosteronismo/fisiopatologia , Hipoaldosteronismo/terapia , Lactente , Rim/fisiopatologia , Masculino , Erros Inatos do Metabolismo/complicações , Erros Inatos do Metabolismo/tratamento farmacológico , Erros Inatos do Metabolismo/fisiopatologia , Erros Inatos do Metabolismo/terapia , Vitamina B 12/uso terapêuticoRESUMO
Disorders regarding peristomal skin have been more and more investigated in order to establish the impact on quality of life of ostomy patients. The aim of this classification is to provide an objective, standardized tool for the assessment of peristomal skin complication specifically designed on the description and localization of the lesion.
Assuntos
Dermatopatias/classificação , Dermatopatias/etiologia , Estomas Cirúrgicos/efeitos adversos , Colostomia/efeitos adversos , Humanos , Ileostomia/efeitos adversos , Itália , Pesquisa , Dermatopatias/diagnóstico , Dermatopatias/prevenção & controle , Fatores de Tempo , Ureterostomia/efeitos adversosRESUMO
OBJECTIVES: To determine the ability of neutrophils isolated from HIV-seropositive patients to produce proinflammatory cytokines. DESIGN: The in vitro responsiveness of polymorphonuclear neutrophils (PMN) and peripheral blood mononuclear cells (PBMC) to lipopolysaccharide (LPS), used in the presence or absence of interferon (IFN)gamma, was determined in 47 HIV-positive patients with advanced stages of virus infection. METHODS: Cytokines in cell-free supernatants were measured by enzyme-linked immunosorbent assay or radioimmunoassay. RESULTS: Cell-free supernatants from PMN isolated from the peripheral blood of HIV-positive patients and stimulated with LPS contained increased amounts of tumour necrosis factor (TNF)-alpha and interleukin (IL)-8 with respect to supernatants obtained from PMN of normal donors. In contrast, release of IL-1beta and IL-1ra (IL-1 receptor antagonist) in response to LPS, or LPS plus IFNgamma, was found to be lower in PMN from HIV-positive patients than in PMN from controls, but was significant only in the case of IL-1ra. Furthermore, the release of IL-12 induced by LPS or LPS plus IFNgamma did not significantly differ between PMN from HIV-positive patients and healthy donors. Concerning PBMC, the production of TNF-alpha and IL-12 in response to LPS, or LPS plus IFNgamma, was found to be significantly higher in cells isolated from HIV-positive patients, whereas the release of IL-1beta was significantly lower. In the case of IL-8, no statistically significant difference was found between PBMC isolated from HIV-positive patients and healthy donors. CONCLUSIONS: Collectively, the data suggest that in HIV-positive patients with advanced stages of disease, the ability of PMN to produce specific cytokines in response to LPS is significantly altered. Alterations in this ability might contribute to the evolution of HIV disease.
Assuntos
Citocinas/biossíntese , Infecções por HIV/imunologia , Neutrófilos/imunologia , Adolescente , Adulto , Animais , Quimiocina CCL4 , Citocinas/imunologia , Feminino , Humanos , Interferon gama/farmacologia , Proteína Antagonista do Receptor de Interleucina 1 , Interleucinas/biossíntese , Leucócitos Mononucleares/imunologia , Lipopolissacarídeos/farmacologia , Proteínas Inflamatórias de Macrófagos/biossíntese , Masculino , Neutrófilos/efeitos dos fármacos , Radioimunoensaio , Sialoglicoproteínas/biossíntese , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Granulocyte colony-stimulating factor (G-CSF) has been recently shown to induce the high-affinity Fc receptor for IgG (Fc(gammaRI)/CD64) in human polymorphonuclear neutrophils (PMN). To elucidate the molecular mechanisms whereby G-CSF exerts this effect, we examined whether the cytokine induces the binding of transcription factors to the IFNgamma response region (GRR), a well characterized regulatory element in the Fc(gammaRI) promoter that is responsible for the transcriptional induction of this gene. Using electrophoretic mobility shift assays, we show that in human PMN, G-CSF activates a GRR-binding complex which contains members of the signal transducer and activator of transcription (STAT) family of proteins, namely STAT1 and STAT3. In keeping with this result, treatment of neutrophils with G-CSF led to tyrosine phosphorylation of STAT3, as determined by immunoprecipitation followed by immunoblotting with antiphosphotyrosine antibodies. This is the first demonstration that in human neutrophils, the induction by G-CSF of Fc(gammaRI) gene expression may be mediated by the binding of STAT1 and STAT3 to the GRR sequence.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Fator Estimulador de Colônias de Granulócitos/farmacologia , Neutrófilos/metabolismo , Regiões Promotoras Genéticas , Receptores de IgG/genética , Transativadores/metabolismo , Sítios de Ligação , Elementos Facilitadores Genéticos , Regulação da Expressão Gênica , Humanos , Interferon gama , Ligação Proteica , Fator de Transcrição STAT1 , Fator de Transcrição STAT3RESUMO
GRO alpha, a member of the chemokine superfamily, exerts potent stimulatory actions on granulocytes. In this report, we show that activated human polymorphonuclear leukocytes (PMN) are able to produce significant amounts of GRO alpha. Lipopolysaccharide (LPS), tumor necrosis factor-alpha (TNF alpha), and yeast particles opsonized with IgG (Y-IgG) had the ability to induce GRO alpha release, with Y-IgG being the most potent stimulus. The extracellular production of GRO alpha was also modulated by both interferon-gamma (IFN gamma) and interleukin-10 (IL-10). IFN gamma significantly inhibited the production of GRO alpha by PMN stimulated for 2 hr with LPS, TNF alpha, or Y-IgG, but potentiated the production of GRO alpha in cells stimulated for 18 hr with LPS and TNF alpha. IL-10 moderately suppressed the Y-IgG-induced production of GRO alpha, but strongly inhibited the action of LPS and potentiated the effect of TNF alpha. As revealed by Northern blot analysis, the extracellular production of GRO alpha under the experimental conditions used did not always correlate with parallel changes at the level GRO alpha mRNA expression, suggesting that production of GRO alpha by PMN might be regulated at post-transcriptional, translational, or post-translational level. These findings identify a novel biological function of PMN, likely involved in the modulation of the acute inflammatory response.
Assuntos
Quimiocinas CXC , Fatores Quimiotáticos/biossíntese , Inibidores do Crescimento/biossíntese , Substâncias de Crescimento/biossíntese , Peptídeos e Proteínas de Sinalização Intercelular , Neutrófilos/metabolismo , Quimiocina CXCL1 , Fatores Quimiotáticos/genética , Sinergismo Farmacológico , Expressão Gênica , Inibidores do Crescimento/genética , Substâncias de Crescimento/genética , Humanos , Imunoglobulina G/farmacologia , Interferon gama/farmacologia , Interleucina-10/farmacologia , Lipopolissacarídeos/farmacologia , Proteínas Opsonizantes , RNA Mensageiro/metabolismo , Saccharomyces cerevisiae , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
Cyclosporin (CsA) and azathioprine (AZA) are useful immunosuppressive drugs in the management of kidney and liver transplant recipients. We investigated urinary mutagenicity in three groups of kidney transplant recipients after different immunosuppressive protocols. Urinary mutagenicity was detected in a base-pair strain, E. coli WP2uvrA, in a liquid incubation assay. No mutagenic activity was detected in the urines of patients treated with CsA (4.5 mg/kg); 85% of the urines in the second group treated with AZA (1.26 mg/kg) showed high mutagenic activity, whereas mutagenic activity was found in 40% of the urines of subjects treated with CsA and AZA (3.89 mg/kg + 1.15 mg/kg). These data suggest that immunosuppressive therapy with AZA carriers a high risk of urinary mutagenicity, while immunosuppressive combined treatment with CsA and AZA significantly reduces this risk.
Assuntos
Imunossupressores/efeitos adversos , Transplante de Rim , Testes de Mutagenicidade/métodos , Mutagênicos/metabolismo , Animais , Azatioprina/efeitos adversos , Ciclosporina/efeitos adversos , Escherichia coli/efeitos dos fármacos , Humanos , Imunossupressores/urina , Técnicas In Vitro , Mutagênicos/efeitos adversos , Prednisolona/efeitos adversos , Ratos , Urina/químicaAssuntos
Caveolina 3/genética , Aberrações Cromossômicas , Deleção Cromossômica , Análise Mutacional de DNA , Genes Recessivos/genética , Cãibra Muscular/genética , Debilidade Muscular/genética , Doenças Musculares/genética , Adulto , Biópsia , Creatina Quinase/sangue , Eletromiografia , Éxons/genética , Feminino , Triagem de Portadores Genéticos , Genótipo , Humanos , Contração Muscular/genética , Cãibra Muscular/diagnóstico , Debilidade Muscular/diagnóstico , Músculo Esquelético/patologia , Doenças Musculares/diagnóstico , Exame Neurológico , Linhagem , Reação em Cadeia da Polimerase , Polimorfismo de Nucleotídeo Único/genética , Receptores de Ocitocina/genéticaRESUMO
Carbamoyl Phosphate Synthetase 1 deficiency (CPS1D) is a rare autosomal recessive urea cycle disorder, potentially leading to lethal hyperammonemia. Based on the age of onset, there are two distinct phenotypes: neonatal and late form. The CPS1 enzyme, located in the mitochondrial matrix of hepatocytes and epithelial cells of intestinal mucosa, is encoded by the CPS1 gene. At present more than 220 clear-cut genetic lesions leading to CPS1D have been reported. As most of them are private mutations diagnosis is complicated. Here we report an overview of the main clinical findings and biochemical and molecular data of 13 CPS1D Italian patients. In two of them, one with the neonatal form and one with the late form, cadaveric auxiliary liver transplant was performed. Mutation analysis in these patients identified 17 genetic lesions, 9 of which were new confirming their "private" nature. Seven of the newly identified mutations were missense/nonsense changes. In order to study their protein level effects, we performed an in silico analysis whose results indicate that the amino acid substitutions occur at evolutionary conserved positions and affect residues necessary for enzyme stability or function.
Assuntos
Carbamoil-Fosfato Sintase (Amônia)/genética , Doença da Deficiência da Carbamoil-Fosfato Sintase I/genética , Adolescente , Adulto , Doença da Deficiência da Carbamoil-Fosfato Sintase I/diagnóstico , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Lactente , Recém-Nascido , Itália , Masculino , MutaçãoRESUMO
OBJECTIVE: The aim of the study was to assess different outcome measures in a cohort of ambulant boys with Duchenne muscular dystrophy (DMD) over 12 months in order to establish the spectrum of possible changes in relation to age and steroid treatment. METHODS: The study is a longitudinal multicentric cohort study. A total of 106 ambulant patients with DMD were assessed using the 6-minute walk test (6MWT) and North Star Ambulatory Assessment (NSAA) at baseline and 12 months. Clinical data including age and steroid treatment were collected. RESULTS: During the 12 months of the study, we observed a mean decline of 25.8 meters in the 6MWT with a SD of 74.3 meters. On NSAA, the mean decline was 2.2 points with a SD of 3.7. Not all the boys with DMD in our cohort showed a decline over the 12 months, with young boys showing some improvement in their 6MWT and NSAA scores up to the age of 7. NSAA and the 6MWT had the highest correlation (r = 0.52, p < 0.001). CONCLUSIONS: This study provides longitudinal data of NSAA and 6MWT over a 12-month period. These data can be useful when designing a clinical trial.
Assuntos
Distrofia Muscular de Duchenne/fisiopatologia , Adolescente , Anti-Inflamatórios/uso terapêutico , Criança , Pré-Escolar , Estudos de Coortes , Estudos Transversais , Progressão da Doença , Feminino , Humanos , Masculino , Distrofia Muscular de Duchenne/tratamento farmacológico , Prednisolona/uso terapêutico , Pregnenodionas/uso terapêutico , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Estatística como Assunto , Caminhada/fisiologiaRESUMO
In an expanded newborn screening program for inborn errors of metabolism by LC-MS/MS in Tuscany, six newborns out of 169,000 showed decreased blood citrulline levels. In one of them, molecular analysis of the OTC gene identified the known p.Trp265Leu mutation, which is correlated with late-onset ornithine transcarbamylase deficiency (OTCD). Hypocitrullinemia is not a reliable marker for OTCD newborn screening, especially for late-onset forms that may exhibit normal citrulline levels. However, when hypocitrullinemia is detected in a newborn in whom intestinal dysfunction and prematurity have been excluded, OTCD should be investigated first because of the OTCD incidence (1:14,000) and the small size of the OTC gene coding sequence.
Assuntos
Cromatografia Líquida/métodos , Triagem Neonatal/métodos , Doença da Deficiência de Ornitina Carbomoiltransferase/genética , Ornitina Carbamoiltransferase/genética , Espectrometria de Massas em Tandem/métodos , Biomarcadores/sangue , Citrulina/sangue , Feminino , Humanos , Incidência , Recém-Nascido , Itália/epidemiologia , MasculinoRESUMO
The diagnosis of glycogenosis type II is often complicated by the rarity of the condition and the heterogeneity of the clinical manifestations of the disease. It is a progressive, debilitating, and often fatal neuromuscular disorder that manifests as a continuum of clinical phenotypes, which vary with respect to organ involvement, age at onset, and severity. Early diagnosis requires both increased awareness among physicians regarding the clinical characteristics of the disease and fast and reliable acid alpha-glucosidase (GAA) enzyme activity assays to confirm the GAA deficiency. The clinical diagnosis of glycogenosis type II is confirmed by virtual absence (found in infants) and marked reduced activity (found in juveniles and adults) of GAA enzyme in blood samples, cultured fibroblasts, and muscle biopsies. This article specifically highlights the need for early recognition of the clinical manifestation of the disease in infants, juveniles, and adults. Descriptions of the main clinical features of the condition, as well as differential diagnosis are included. In addition, the tests required for a confirmed diagnosis are described, and use of muscle imaging to evaluate muscle pathology is reviewed.