LC–MS/MS assays to quantify sulfatides and lysosulfatide in cerebrospinal fluid of metachromatic leukodystrophy patients

Aim: Two separate LC–MS/MS assays were developed to quantitate sulfatides and lysosulfatide in human cerebrospinal fluid (CSF). Materials & methods: Lysosulfatide and the 15 most abundant sulfatide species were quantitated by LC–MS/MS using artificial CSF as surrogate matrix to prepare calibration curves. Results: Validation criteria were met (linear range: 0.02–1.00 μg/ml sulfatides [0.02–1.00 ng/ml lysosulfatide]); accuracy/precision were within ±15%. CSF from 21 children with metachromatic leukodystrophy had significantly higher sulfatide and lysosulfatide concentrations than CSF from 60 healthy children (p < 0.0001). Worse motor function correlated with higher CSF sulfatide (p = 0.0087) and lysosulfatide (p = 0.0034) levels. Conclusion: These assays, validated in patients with metachromatic leukodystrophy, may aid the clinical assessment of therapeutic responses.