Direct tandem mass spectrometric profiling of sulfatides in dry urinary samples for screening of metachromatic leukodystrophy.

Abstract

BACKGROUND:

Prediagnostic steps in suspected metachromatic leukodystrophy (MLD) rely on clinical chemical methods other than enzyme assays. We report a new diagnostic method which evaluates changes in the spectrum of molecular types of sulfatides (3-O-sulfogalactosyl ceramides) in MLD urine.

METHODS:

The procedure allows isolation of urinary sulfatides by solid-phase extraction on DEAE-cellulose membranes, transportation of a dry membrane followed by elution and tandem mass spectrometry (MS/MS) analysis in the clinical laboratory. Major sulfatide isoforms are normalized to the least variable component of the spectrum, which is the indigenous C18:0 isoform. This procedure does not require the use of specific internal standards and minimizes errors caused by sample preparation and measurement.

RESULTS:

Urinary sulfatides were analyzed in a set of 21 samples from patients affected by sulfatidosis. The combined abundance of the five most elevated isoforms, C22:0, C22:0-OH, C24:0, C24:1-OH, and C24:0-OH sulfatides, was found to give the greatest distinction between MLD-affected patients and a control group.

CONCLUSIONS:

The method avoids transportation of liquid urine samples and generates stable membrane-bound sulfatide samples that can be stored at ambient temperature. MS/MS sulfatide profiling targeted on the most MLD-representative isoforms is simple with robust results and is suitable for screening.

• Authors: Ladislav Kuchař, Befekadu Asfaw, Helena Poupětová, Jitka Honzíková, František Tureček, Jana Ledvinová
• Journal: Clinica chimica acta; international journal of clinical chemistry (Clin Chim Acta) Vol. 425 Pg. 153-9 (Oct 21 2013) ISSN: 1873-3492 [Electronic] Netherlands
• PMID: 23838369 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © 2013.

Chemical References

• Membranes, Artificial
• Sulfoglycosphingolipids
• DEAE-Cellulose

Topics

• Adolescent
• Case-Control Studies
• Child
• Child, Preschool
• DEAE-Cellulose
• Desiccation
• Female
• Humans
• Infant
• Leukodystrophy, Metachromatic (diagnosis, urine)
• Male
• Membranes, Artificial
• Middle Aged
• Reference Standards
• Solid Phase Extraction
• Specimen Handling (standards)
• Sulfoglycosphingolipids (urine)
• Tandem Mass Spectrometry