PRENATAL-DIAGNOSIS OF GALACTOSEMIA

The experience from three different European centres with the prenatal diagnosis of galactose-1-phosphate-uridyltransferase (GALT) deficienc y is presented and the question whether or not there is a need for pre natal diagnosis of this disorder is discussed. Most prenatal diagnoses (n = 50) have been performed by assay of GALT activity in cultured am niotic fluid cells. The assay used is reliable and clearly distinguish es homozygous affected fetuses (n = 11; 0%-2.3% of mean control enzyme activity) from non-(homozygous)-affected fetuses. The GALT assay for cultured amniocytes was adapted to assay the enzyme directly in chorio nic villi. The experience with chorionic villi comprises 23 cases with 5 affected fetuses (0%-4.2% of mean control enzyme activity). In 36 c ases galactitol was determined in amniotic fluid supernatant by gas ch romatography-mass spectrometry. This method also differentiated affect ed (n = 11; galactitol 5.9-10.6 mu mol/l) and unaffected pregnancies ( galactitol 0.23-1.6 mu mol/l) clearly and has the advantage of providi ng a result within a day or two after amniocentesis. Prenatal diagnosi s of galactosemia is undertaken rarely and sometimes for the wrong rea sons, but it should perhaps be considered more seriously until better methods of treatment are established.