Rapid diagnosis of late-onset Pompe disease by fluorometric assay of α-glucosidase activities in dried blood spots

Kallwass, Helmut; Carr, Cortney; Gerrein, Joseph; Titlow, Mariah; Pomponio, Robert J.; Bali, Deeksha; Dai, Jinghong; Kishnani, Priya S.; Skrinar, Alison; Corzo, Deyanira; Keutzer, Joan

doi:10.1016/j.ymgme.2006.12.006

Cited by 54 publications

(35 citation statements)

References 18 publications

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“…With the fluorogenic substrate 4-methylumbelliferyl-␣-glucoside, acarbose concentrations of 3-9 mol/L are sufficient to inhibit maltase glucoamylase activity in the assay (8,9 ). We found that with the synthetic substrate in this assay, 8 mol/L acarbose provided sufficient inhibition of maltase glucoamylase and maintenance of GAA activity (Supplemental Fig.…”

mentioning

confidence: 70%

Multiplex Enzyme Assay Screening of Dried Blood Spots for Lysosomal Storage Disorders by Using Tandem Mass Spectrometry

Zhang¹,

Elbin²,

Chuang³

et al. 2008

Clinical Chemistry

163

143

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Background: Reports of the use of multiplex enzyme assay screening for Pompe disease, Fabry disease, Gaucher disease, Niemann-Pick disease types A and B, and Krabbe disease have engendered interest in the use of this assay in newborn screening. We modified the assay for high-throughput use in screening laboratories. Methods: We optimized enzyme reaction conditions and procedures for the assay, including the concentrations of substrate (S) and internal standard (IS), assay cocktail compositions, sample clean-up procedures, and mass spectrometer operation. The S and IS for each enzyme were premixed and bottled at an optimized molar ratio to simplify assay cocktail preparation. Using the new S:IS ratio, we validated the modified assay according to CLSI guidelines. Stability of the S, IS, and assay cocktails were investigated. Dried blood spots from 149 healthy adults, 100 newborns, and 60 patients with a lysosomal storage disorder (LSD) were tested using the modified assay. Results: In our study, the median enzyme activity measured in adults was generally increased 2–3–fold compared to the original method, results indicating higher precision. In the multiplex format, each of the 5 modified enzyme assays enabled unambiguous differentiation between samples from healthy individuals (adults and newborns) and the corresponding disease-specific samples. Conclusions: The modified multiplex enzyme assay with premixed S and IS is appropriate for use in high-throughput screening laboratories.

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mentioning

confidence: 70%

Multiplex Enzyme Assay Screening of Dried Blood Spots for Lysosomal Storage Disorders by Using Tandem Mass Spectrometry

Zhang¹,

Elbin²,

Chuang³

et al. 2008

Clinical Chemistry

163

143

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“…This finding was demonstrated in the present study, where total catalytic activity was not different between the healthy controls and the patients (p < 0.176). A modified technique was used based on the one reported by Kallwass et al (2007) and Li et al (2004), which permitted the discrimination of the activity of the different isoforms using acarbose as an inhibitor. This method achieved significant differences between the controls and the individuals affected by Pompe disease (see Table 3).…”

Section: Resultsmentioning

confidence: 99%

“…The analysis of a-glucosidase was performed according to a standardized methodology described by Kallwass et al (2007) and Li et al (2004). The analysis of arylsulfatase B was performed using a standardized methodology based on the analytical principle of the leukocyte analysis proposed by Shapira et al (1989) and Civallero et al (2006).…”

Section: Sample Collection For the Controls And Patients In The Studymentioning

confidence: 99%

Selective Screening for Lysosomal Storage Diseases with Dried Blood Spots Collected on Filter Paper in 4,700 High-Risk Colombian Subjects

Uribe

Giugliani

2013

JIMD Reports

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Lysosomal storage disorders (LSDs) are a very heterogeneous group of hereditary disorders. The diagnostic process usually involves complex sampling, processing, testing, and validation procedures, performed by specialized laboratories only, which causes great limitations in reaching a diagnosis for patients affected by these diseases.There are few studies about LSDs in Colombia. The diagnostic limitations often make medical practitioners disregard the possibility of these disorders while diagnosing their patients. The current study documents the results of a 7-year screening in high-risk patients, aimed to detect LSDs using dried blood spots (DBS) collected on filter paper, with a micromethodology that facilitates diagnosis even with a large number of samples.The activities of a-galactosidase A, a glucosidase, a-Liduronidase, arylsulfatase B, b-galactosidase, b-glucosidase, total hexosaminidase, iduronate sulfatase, and chitotriosidase were analyzed in high-risk patients for lysosomal disease. The catalytic activity was evaluated with fluoro-

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“…1.2-6.4 (n = 68) 0.4-3.6 (n = 50) D91N / D91N homozygotes 11; 11 (n = 2) Not available D91N/c.j32j13T>G compound heterozygotes 5.7; 7.9 (n = 2) Not available Ratio (0.7 mmol/L MU-aGlc, no acarbose)/(0.7 mmol/L MU-aGlc +8 mmol/L acarbose) Controls 1.7-3.3 (n = 37) 3.6-11.4 (n = 51) Patients (non-classic phenotypes) (n = 50) 5.9-10 0.7-14.7 (5.9 T 4.0) procedures with a final MU-aGlc concentration of 0.7 mmol/L, with or without 8 mmol/L acarbose, at pH 3.8, were employed to mimic the conditions for the acid a-glucosidase activity determinations in DBS (Chien et al 2008;Gasparotto et al 2008;Kallwass et al 2007). The inter-assay coefficients of variation (CV) for leukocytes (n = 20) were, 13.7% for the glycogen assay, and 14.4%, 13.1% and 16.3% and for the three MU assays.…”

Section: Leukocytes Lymphocytesmentioning

confidence: 99%

“…This problem seems to be confined to assays in which 4-methylumbelliferyl-a-D-glucoside (MU-aGlc), a convenient but artificial substrate, is used (Okumiya et al 2006;Winchester et al 2008). For unknown reasons, it might be easier to distinguish patients from unaffected controls when this artificial substrate is used in an assay on dried blood spots (DBS) (Chien et al 2008;Kallwass et al 2007;Zhang et al 2006). Notably, methods based on the use of MU-aGlc and tandem mass spectrometry are being tested for newborn screening in Pompe disease (Chien et al 2008;Dajnoki et al 2008;De Jesus et al 2009;Gasparotto et al 2008;Gelb et al 2006;Li et al 2004;Zhang et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Enzyme analysis for Pompe disease in leukocytes; superior results with natural substrate compared with artificial substrates

Diggelen

Oemardien²,

Beek³

et al. 2009

J of Inher Metab Disea

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Enzyme analysis for Pompe disease in leukocytes has been greatly improved by the introduction of acarbose, a powerful inhibitor of interfering alpha-glucosidases, which are present in granulocytes but not in lymphocytes. Here we show that the application of acarbose in the enzymatic assay employing the artificial substrate 4-methylumbelliferyl-alpha-D: -glucoside (MU-alphaGlc) is insufficient to clearly distinguish patients from healthy individuals in all cases. Also, the ratios of the activities without/with acarbose only marginally discriminated Pompe patients and healthy individuals. By contrast, when the natural substrate glycogen is used, the activity in leukocytes from patients (n = 82) with Pompe disease is at most 17% of the lowest control value. The use of artificial substrate in an assay with isolated lymphocytes instead of total leukocytes is a poor alternative as blood samples older than one day invariably yield lymphocyte preparations that are contaminated with granulocytes. To diagnose Pompe disease in leukocytes we recommend the use of glycogen as substrate in the presence of acarbose. This assay unequivocally excludes Pompe disease. To also exclude pseudo-deficiency of acid alpha-glucosidase caused by the sequence change c.271G>A (p.D91N or GAA2; homozygosity in approximately 1:1000 caucasians), a second assay employing MU-alphaGlc substrate plus acarbose or DNA analysis is required.

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Rapid diagnosis of late-onset Pompe disease by fluorometric assay of α-glucosidase activities in dried blood spots

Cited by 54 publications

References 18 publications

Multiplex Enzyme Assay Screening of Dried Blood Spots for Lysosomal Storage Disorders by Using Tandem Mass Spectrometry

Multiplex Enzyme Assay Screening of Dried Blood Spots for Lysosomal Storage Disorders by Using Tandem Mass Spectrometry

Selective Screening for Lysosomal Storage Diseases with Dried Blood Spots Collected on Filter Paper in 4,700 High-Risk Colombian Subjects

Enzyme analysis for Pompe disease in leukocytes; superior results with natural substrate compared with artificial substrates

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