?-l-Iduronidase activity in leukocytes: Diagnosis of homozygotes and heterozygotes of the Hurler syndrome

Omura, Kiyoshi; Higami, Shinobu; Tada, Keiya

doi:10.1007/bf00466268

Cited by 11 publications

(6 citation statements)

References 7 publications

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“…Biochemical diagnosis of LSD is performed by determination of enzymatic activities in different biological fluids (as plasma, leukocytes, fibroblasts and most recently dried blood spots on filter paper (DBS)), using fluorimetry, immunocapture and mass spectrometry assays [4-8]. One of the advantages for the use of DBS in the diagnosis of LSD is that these samples may be transported safely through long distances, including mailing in regular envelopes, because enzyme activities remain stable for months at room temperature [8].…”

Section: Introductionmentioning

confidence: 99%

Reference values for lysosomal enzymes activities using dried blood spots samples - a Brazilian experience

et al. 2010

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BackgroundLysosomal storage diseases (LSD) are inherited disorders caused by deficiency of lysosomal enzymes in which early diagnosis is essential to provide timely treatment. This study reports interval values for the activity of lysosomal enzymes that are deficient in Mucopolysaccharidosis type I, Fabry, Gaucher and Pompe disease, using dried blood spots on filter paper (DBS) samples in a Brazilian population.ResultsReference activity values were obtained from healthy volunteers samples for alpha-galactosidase A (4.57 ± 1.37 umol/L/h), beta-glucosidase (3.06 ± 0.99 umol/L/h), alpha-glucosidase (ratio: 13.19 ± 4.26; % inhibition: 70.66 ± 7.60), alpha-iduronidase (3.45 ± 1.21 umol/L/h) and beta-galactosidase (14.09 ± 4.36 umol/L/h).ConclusionReference values of five lysosomal enzymes were determined for a Brazilian population sample. However, as our results differ from other laboratories, it highlights the importance of establishing specific reference values for each center.

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Section: Introductionmentioning

confidence: 99%

Reference values for lysosomal enzymes activities using dried blood spots samples - a Brazilian experience

et al. 2010

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“…Wappner & Brant (1976), in a study of (c-L-iduronidase activity in leucocyte supernatant preparations from 16 obligate heterozygotes, did not observe overlap with their normal range. Other studies, using considerably lower numbers of heterozygotes than Wappner & Brant, also report complete separation of obligate heterozygote and normal ranges of leucocyte a-L-iduronidase activities assayed with phenyl a-L-iduronide as substrate (Liem & Hooghwinkel, 1975;Omura et al, 1976; Momoi et al, 1977).…”

Section: !Ler and A C Poliardmentioning

confidence: 92%

“…With the artificial substrate, phenyl GLiduronide, cc-L-iduronidase activity has been demonstrated to be reduced in leucocytes, serum and cultured skin fibroblasts from obligate heterozygotes for Hurler and Scheie syndromes (Hall & Neufeld, 1973;Singh et al, 1974;Dulaney et al, 1976;Wappner & Brandt, 1976;Liem & Hooghwinkel, 1975;Omura, Higami & Tada, 1976;Momoi, Sudo, Tanioka & Kushida, 1977). Wappner & Brant (1976), in a study of (c-L-iduronidase activity in leucocyte supernatant preparations from 16 obligate heterozygotes, did not observe overlap with their normal range.…”

Section: !Ler and A C Poliardmentioning

confidence: 99%

Post- and Pre-Natal Assessment of α-l-Iduronidase Deficiency with a Radiolabelled Natural Substrate

1979

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1. a-L-Iduronidase activity was assayed by incubation of iduronosyl anhydro[ l-3H]mannitol 6-sulphate with homogenates of cultured skin fibroblasts, amniotic cells and leucocytes derived from normal individuals, patients affected with GLiduronidase deficiency disorder (mucopolysaccharidosis type I: Hurler, Scheie and Hurler-Scheie compound) and parents of such patients.2. The assay for cc-L-iduronidase, described for use with these cell types, clearly distinguished affected homozygotes from heterozygotes and normal controls.3. The mean specific activity of a-L-iduronidase in homogenates prepared from cultured skin fibroblasts and leucocytes from more than seven obligate heterozygotes for mucopolysaccharidosis type I was found to be about one-half of the mean of more than 40 normal controls. A number of heterozygotes had a-L-iduronidase activity that identified them as carriers; others had values clearly within the normal range. Thus heterozygote detection of mucopolysaccharidosis type I is not certain.4. With iduronosyl anhydr~[l-~Hlmannitol 6sulphate used as substrate, cell types from five pregnancies at risk for a-L-iduronidase deficiency were examined; each foetus was predicted to be unaffected. For one foetus it was not possible from measurements of total enzyme activity alone to distinguish between the heterozygous carrier state and

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“…According to availability of DBS samples, development of DBS-based enzyme activity measurement is highly desirable. Enzyme activity can be determined by methods such as fluorometric assay, radioactive labeled substrates, Immunocapture and mass spectrometry [1,[5][6][7][8]. Because of novelty of method, there is little research on method validation, hence, for the first time in Iran we aimed this study to evaluate the validity of fluorometric assay of a-L-Iduronidase activity in DBS samples for diagnosis of MPS I.…”

Section: Introductionmentioning

confidence: 99%

Determination of Biological Variance and Validation of a Fluorometric Assay for Measurement of α-l-Iduronidase Activity in Dried Blood Spots Samples: The First Experience in Iran

et al. 2014

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Methods for assaying lysosomal diseases in dried blood samples are very useful today due to its several advantages related to the stability of samples, its transportation, handled and analysis, and its potential use for newborn screening compared to traditional methods in leucocytes samples. For this reason, it is important to validate these assays before being used in routine laboratory. Because of different in biological markers based on ethnicity, we aimed this study to validation a DBS-based fluorometric assay for measurement of a-L-Iduronidase activity for diagnosis of MPS I patients in Iran. DBS samples were collected from 15 MPS I patients and 60 healthy age matched subjects. Diagnostic value, biological variance and a-L-Iduronidase activity were determined. DBS a-L-Iduronidase activity was significantly higher in male subjects than in female group. Using a cut-off level of 1.08 lmol/spot 20 h, sensitivity and specificity were 100 and 98 %. The linearity of test was proved and we showed that within-run and between run precision were 5.6 and 14.66 %. Measurement of a-L-Iduronidase activity in DBS samples is an accurate test for diagnosis of MPS I and because of its rapid shipping and simplicity to keeping, DBS-based enzyme activity could be considered as a useful diagnostic tool in this disease.

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?-l-Iduronidase activity in leukocytes: Diagnosis of homozygotes and heterozygotes of the Hurler syndrome

Cited by 11 publications

References 7 publications

Reference values for lysosomal enzymes activities using dried blood spots samples - a Brazilian experience

Reference values for lysosomal enzymes activities using dried blood spots samples - a Brazilian experience

Post- and Pre-Natal Assessment of α-l-Iduronidase Deficiency with a Radiolabelled Natural Substrate

Determination of Biological Variance and Validation of a Fluorometric Assay for Measurement of α-l-Iduronidase Activity in Dried Blood Spots Samples: The First Experience in Iran

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