Diagnosis of arylsulfatase A deficiency in intact cultured cells using a fluorescent derivative of cerebroside sulfate

A fluorescent derivative of cerebroside sulfate (12‐(l‐pyrene)dodecanoyl‐sphingosylgalactosyl‐0–3‐sulfate (P12‐sulfatide) has been synthesized as a potential substrate for the determination of cerebroside sulfatidase (or arylsulfatase A) activity. It was administered into cultured human skin fibroblasts and thereby utilized for the diagnosis of arylsulfatase A deficiency. Cultured skin fibroblasts from normal individuals and healthy persons suffering from a pseudoarylsulfa‐tase A deficiency (PD) degraded the P12‐sulfatide, while in cells derived from a metachromatic leukodystrophy (MLD) patient it remained essentially intact. This contrasts with in vitro determinations of enzymatic activity, where the MLD or PD‐derived arylsulfatase A exhibit similar deficiency, in spite of a profoundly different clinical course. Administration of the fluorescent sulfatide into the intact cells permitted a sensitive and rapid diagnosis of MLD and its distinction from the PD‐phenomenon. This might be of particular importance for cases in which a rapid diagnosis is required and for prenatal diagnosis of fetuses from families afflicted with both MLD and pseudo‐deficiency mutant genes.