Two readily obtainable biological fluids, i.e., urine and tears, were investigated as possible substitutes for serum and leukocytes for the detection of Tay-Sachs disease (TSD) heterozygotes based on Quantitative hexosaminidase A (Hex A) determinations. 2. Hexosaminidase isoenzyme patterns were determined, by means of an automated DEAE-cellulose microcolumn procedure, for serum, urine and tear samples from normals, TSD carriers, normal pregnancies, carrier-pregnancies and TSD children. 3. Normal pregnancy and TSD carrier sera gave almost identical hexosaminidase patterns with multiple intermediate peaks. Whereas, urine and tear samples from normal pregnant women showed hexosaminidase isoenzyme patterns resembling those of normal controls. These results suggested that use of these fluids might eliminate the effect of pregnancy of the Hex A ratio which occurs when serum is used as the test fluid. In addition these fluids are most economical and simpler to obtain than a blood sample. 4. About 200 urine samples, from the various categories listed above, were analyzed for Hex A with both the heat denaturation and pH inactivation methods and the results compared with serum and leukocyte levels from many of the same individuals. With either method, the wide overlap between the urinary Hex A normal and heterozygote ranges would require retesting with leukocytes of about 30% of the subjects. These results would preclude the use of urines as a suitable fluid for the mass screening of the Ashkenazic Jewish population for TSD heterozygotes.
