Diagnosis of Morquio Syndrome in Dried Blood Spots Based on a New MRM-MS Assay.
PLoS One
; 10(7): e0131228, 2015.
Article
em En
| MEDLINE
| ID: mdl-26147980
ABSTRACT
BACKGROUND:
Mucopolysaccharidosis IVA (MPS IVA; Morquio A disease) is an autosomal recessive disease caused and characterized by a decreased activity of N-acetylgalactosamine-6-sulfate sulfatase (GALNS), resulting in accumulation of keratan sulfate and chondroitin-6-sulfate in tissues and secondary organ damage. Recently approved enzyme replacement therapy renders the easy and early identification of MPS IVA of out-most importance.METHODOLOGY:
We propose a completely new assay for the stable and reproducible detection of GALNS deficiency in dry blood spots (DBS). For the validation blood samples were taken from 59 healthy individuals and 24 randomly selected genetically confirmed MPS IVA patients. The material extracted from DBS was incubated with a 4-methylumbelliferyl-ß-D-galactopyranoside-6-sulfate as a specific substrate. Final enzymatic product, 4-methylumbelliferone, obtained after adding exogenous beta-galactosidase, was quantified by LC/MRM-MS (liquid-chromatography/multiple-reaction-monitoring mass-spectrometry). 4-propyl-5-hydroxy-7-methyl-2h-chromen-2-one was used as internal standard, a compound with a similar molecular structure and fragmentation pattern in negative ion mode as 4-methylumbelliferone.FINDINGS:
The enzymatic assay yielded a positive and negative predictive value of 1.0 for genetically confirmed MPS IVA patients (GALNS activity of 0.35 ± 0.21 µmol/L/h) and for controls with normal GALNS activity (23.1 ± 5.3 µmol/L /h). With present enzymatic conditions, the reaction yield in dried blood spots is at least 20 fold higher than any previously reported data with other assays.INTERPRETATION:
The present LC/MRM-MS based assay for MPS IVA diagnosis provides an easy, highly-standardized, accurate and innovative quantification of the enzymatic product in vitro and distinguishes perfectly between MPS IVA affected patients and normal controls. This technique will significantly simplify the early detection of MPS IVA patients.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Espectrometria de Massas
/
Mucopolissacaridose IV
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
/
Screening_studies
Limite:
Humans
Idioma:
En
Revista:
PLoS One
Assunto da revista:
CIENCIA
/
MEDICINA
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Alemanha