Fetal Nucleated Red Blood Cell Counts in Peripheral Blood of Mothers Bearing Down Syndrome Fetus

Currently, prenatal detection of Down syndrome and other most common aneuploidies relies on invasive procedures such as amniocentesis and villocentesis, and on non-invasive screening tests such as second trimester maternal serum screening (Triple test), and first trimester screening (ULTRA-screen). However, it well known that invasive techniques carry a small risk of fetal loss, while both Triple test and ULTRA-screen are not diagnostic, may miss from 15 - 40 % of cases of Down syndrome, in addition to having a 5 - 8 % rate of false-positives. We now report clear evidence that the number of fetal nucleated red blood cells (FNRBCs) in the maternal circulation is remarkably higher in pregnant women carrying aneuploid fetuses, especially in cases of Down syndrome. These results are in agreement with the findings of other investigators using different methods, and suggest that the number of FNRBCs present in the maternal blood sample could be used as additional marker, in concert with existing screening tests, to improve non-invasive detection of Down syndrome, and other most common aneuploidies.

Key words

Fetal cells counts - Hemoglobin F staining - May-Grunwald-Giemsa staining - Down syndrome - Aneuploidies - Prenatal diagnosis

References

• 1 Al-Mufti R, Hambley H, Farzaneh F, Nicolaides K. Investigation of maternal blood enriched for fetal cells: role in screening and diagnosis of fetal trisomies.  Am J Med Genet. 1999;  85 66-75
• 2 Bianchi D W, Williams J M, Sullivan L M, Hanson F W, Klinger K W, Shuber A P. PCR quantitation of fetal cells in maternal blood in normal and aneuploid pregnancies.  Am J Hum Genet. 1997;  61 822-829
• 3 Bianchi D W. Fetal cells in the maternal circulation: feasibility for prenatal diagnosis.  Br J Haematol. 1999;  105 574-583
• 4 Farina A, Bianchi D W. Fetal cells in maternal blood as a second non-invasive step for fetal Down syndrome screening.  Prenat Diagn. 1998;  18 983-984
• 5 Oosterwijk J C, Masker W E, Ouwerkerk-van Velzen M CM, Knepfle C F, Wiesmeijer K C, Beverstock G C, van Ommen G JB, Tanke H J, Kanhai H H. Prenatal diagnosis of trisomy 13 on fetal cells obtained from maternal blood after minor enrichment.  Prenat Diagn. 1998;  18 1082-1085
• 6 Roberts L, Sebire N J, Fowler D, Nicolaides K H. Histomorphological features of chorionic villi at 10 - 14 weeks of gestation in trisomic and chromosomally normal pregnancies.  Placenta. 2000;  21 678-683
• 7 Simpson J L, Elias S. Prenatal diagnosis of aneuploidy using fetal cells isolated from maternal blood. University of Tennessee, Memphis experience.  Ann N Y Acad Sci. 1994;  731 80-91
• 8 Simpson J L, Elias S. Isolating fetal cells from maternal blood. Advances in prenatal diagnosis through molecular technology.  JAMA. 1993;  270 2357-2361
• 9 Takabayashi H, Kuwabara S, Ukita T, Kazumi K, Yamafuji K, Igarashi T. Development of non-invasive fetal DNA diagnosis from maternal blood.  Prenat Diagn. 1995;  15 74-77