To provide a means for the prenatal diagnosis of CGD, we combin ed a modified nitroblue tetrazolium (NBT) slide test with quina crine staining for Y chromosome fluorescence. Blood samples (1 ~1 ) are applied to glass slides and the adherent cells incubate with NBT and phorbol myristate acetate, an activator of oxidative metabolism. Resultant metabolic activity produces microscopically observable formazan particles in 99-100% of adult an 95-100% of fetal granulocytes (PMN), in 0-1% of PMN from 4 CGD patients, and in 18-53% of PMN from 3 obligate CGD carriers. Since placental venipuncture samples are often contaminated wit maternal blood, it is necessary to distinguish fetal and maternal cells in such mixtures. Quinacrine staining reveals a Ybody in 50-90% of male fetal PMN. Such identification of male F?.Nby Y-fluorescence allows detection and assessment of oxidative activity of CGD cells diluted 1:100 in maternal cells. Thus, the modified NBT slide test with quinacrine staining of blood obtained by placental venipuncture provides a method for the prenatal diagnosis of CGD in male fetuses at risk for the X linked or autosomal recessive forms of the disease. Analysis of the physical arrangement of globin genes in cellular DNA is now feasible. High molecular weight DNA is digested with site-specific restriction endonucleases, fractionated in agarose gels, and hybridized with radioactive complementary globin cDNA either in situ or after transfer to nitrocellulose filters. This techniquepermits direct, autoradiographic visualization of DNA fragments containing globin gene sequences in DNA isolated from normal individuals and those with hemoglobinopathies. Comparison of the hybridization patterns of different DNAs provides a convenient, sensitive system for the detection of globin gene deletions or rearrangements. Study of homozygous athalassemia (hydrops fetalis) DNA revealed complete absence of specific DNA fragments containing a globin sequences. The sensitivity and clarity of the visualization of this deletion indicate that this new approach will be especially useful in the prenatal detection of globin gene deletions or rearrangements in amniotic cell DNA of fetuses at risk for severe thalassemia syndromes.A NEW FAMILIAL . . DYSMORPHIC SYNDROME Dustan C. Osborn 1 1 1 0 &lch (Spon. by Richard B. Goldbloom), of Pediatrics, Halifax, N.S. of which show a constellation of features similar to, but distinct frnm t h~ qn-rall~d Nnnnan

suMMARY The combined findings from a number of different analytical techniques increases confidence that the cells analysed in amniotic fluid cell cultures are fetal in origin. Three hundred and twenty four fluids were processed using in situ processing of cultured amniotic fluid cells, allowing for analysis of mitoses from multiple colonies derived from multiple culture dishes. Screening of the same samples for fluorescent Y-chromatin was of help in indicating the genotypic sex of the primary cells. This was found to be accurate in 96% of the fluids checked. In cases where an XX complement is found, Q-polymorphism comparisons can be made between mitoses from the amniotic fluid cells and maternal lymphocytes. Of 29 such studies, 19 showed pronounced differences in their polymorphism constitution.