1. Aspartylglycosaminuria is a neurovisceral storage disease characterized by reduced or absent activity of the lysosomal enzyme N-aspartyl-β-glucosaminidase. Although vacuolization of peripheral lymphocytes is a well-documented feature of aspartylglucosaminuria, the chemical composition of the lymphocyte storage material is not known. In this paper we describe the results of glycopeptide analyses of peripheral lymphocytes isolated from the blood of a 29-year-old female patient with aspartylglycosaminuria and from a control subject.
2. By use of a highly specific and sensitive gaschromatographic-mass-spectrometric technique, 4-N-2-acetamido-2-deoxy-β-d-glucopyranosyl-l-as-paragine (N-acetylglucosaminylasparagine) was found to accumulate in the patient's lymphocytes, but not in those of the control subject.
3. The amount of this compound stored in the diseased lymphocytes was found to be approximately 2·3 nmol/100 μg of soluble protein.
4. We suggest that this compound is the main storage substance in the peripheral lymphocytes in aspartylglucosaminuria and that it is probably responsible for the cytoplasmic vacuolization of these cells.