Barbara Bockel

Risk of fetal Down's syndrome based on maternal age and varying combinations of maternal serum markers.

Serum samples from 320 women with chromosomally normal fetuses and from 50 women with fetuses affected by Downs syndrome were assayed retrospectively for human chorionic gonadotropin (hCG), pregnancy-specificβ1 glycoprotein (SP1), alpha fetoprotein (AFP), and unconjugated estriol (uE3) between 14 and 21 weeks of gestation. Nonparametric discriminant analysis was applied to calculate Down syndrome risks on the basis of various combinations of serum parameters. At a risk threshold that falsely identifies 5% of controls as being affected, 46 to 48% of Down syndrome pregnancies were detected by combinations of hCG/AFP, hCG/AFP/uE3, and hCG/AFP/uE3/SP1 respectively. HCG, AFP, and uE3 were assayed in 652 serum samples from women who underwent amniocentesis because of maternal age (≥35 years in this prospective study). 49% of women with euploid fetal karyotype, 8 of 10 pregnancies with Downs syndrome, and 3 pregnancies with sex chromosomal anomalies were identified as being at an increased risk (>1:380).

Allele frequencies and linkage disequilibrium of polymorphic DNA markers of the Huntington disease region in the German population

Allele frequencies of 14 different restriction fragment length polymorphisms from 12 DNA markers within the Huntington disease (HD) region were evaluated in the German population. No significant differences from published data of allele frequencies from chromosomes of Caucasian ancestry were found. The analysis of eight DNA polymorphisms in 87 HD families of German origin revealed significant non-random association with the HD locus and the D4S95 locus (p674/AccI/MboI), a result that is consistent with all other published studies. These results are confirmed by the fact that the HD gene maps to this region.