Elevated sulfatide excretion in compound heterozygotes of metachromatic leukodystrophy and ASA-pseudodeficiency allele

Objective: Use of sulfatide excretion in differentiating MLD/PD-heterozygotes from MLD-patients and PD/PD-homozygotes. Design and Methods: Sulfatide was extracted from urine sediment with chloroform/methanol (2:1, v/v). The quantity of sulfatide was measured densitometrically (lambda = 580 nm) after thin-layer chromatography. ASA and beta-galactosidase activities were assayed enzymatically. Results: MLD/PD-heterozygotes excreted sulfatide in the range of 4.8-36.3 nmol/mg lipid (mean +/- SD = 17.8 +/- 10.7), whereas sulfatide in MLD-patients ranged from 74.3-411.6 nmol/mg lipid (mean +/- SD = 184.5 +/- 130.8) and in PD/PD-homozygotes sulfatide excretion remained in normal range of 0.0-5.9 nmol/mg lipid (mean +/- SD = 1.64 +/- 2.12). ASA activities in these groups were very low or lowered. Conclusions: The quantitative measurement of sulfatide in urine allows differentiation between MLD/PD-heterozygotes and MLD-heterozygotes, as well as between MLD/PD-heterozygotes with very low ASA activity and MLD-patients or PD/PD-homozygotes. The quantitative measurement of sulfatide in urine differs between MLD-carriers and controls.