Amniotic fluid glycoasparagines in fetal aspartylglycosaminuria.

Midterm amniotic fluid samples from one pregnancy with the fetus affected by aspartylglycosaminuria and from 11 normal pregnancies were analysed for glycoasparagines accumulating in urine in aspartylglycosaminuria. The aspartylglucosamine concentration in the affected pregnancy was about five times higher than in the controls, but the absolute value was very low being only about one-thousandth of that in urine in aspartylglycosaminuria and one-tenth of that in urine samples from normal adults. In total monosaccharide analysis, only galactose content in the affected amniotic fluid was slightly elevated compared to controls, indicating that higher glycoasparagines typical of urine in aspartylglycosaminuria were not accumulated in significant amounts. The data demonstrate that the analysis of glycoasparagines in amniotic fluid is not likely to permit reliable prenatal diagnosis of aspartylglycosaminuria.