Chapter 8
Amniotic Fluid Cells - Uncultured
RENATE ULMER
Introduction
Cytogenetic analysis of fetal cells after amniocentesis is routinely offered
to women who have an increased risk of carrying a fetus with a chromosomal abnormality. Indications for fetal karyotyping include advanced
maternal age, increased risk for fetal trisomy by elements of the triple
screen (i.e. alphafetoprotein, human chorionic gonadotropin, and estriol),
a previous pregnancy with an aneuploid fetus or potential risks due to
family history.
The rate of chromosomal disorders in low-risk groups, like advanced
maternal age is about 2.0%. Rates of >20% of abnormalities are found in
high risk groups with pathological findings in ultrasonography (Eiben et
a1.1997, Claussen et al.1994).
Conventional prenatal diagnosis requires a long-term culture of amniocytes (6-14 days) and is routinely accomplished by GTG banding of
metaphase chromosomes. This technique is accurate and reliable, allowing the detection of a variety of numerical and structural aberrations. Disadvantages are the time-consuming cell-culture and the banding analysis
which requires some experience.
In certain clinical situations (sonographically detected severe fetal abnormalities) a result within the shortest time possible is urgently necessary
for the management of the pregnancy. In other cases, a rapid result could
moderate the anxiety of the pregnant woman, especially in cases such as
an advanced pregnancy, a pathological result of the triple screen, some
conspicuous sonographical findings like nuchal translucency, choroid
plexus cyst and singular umbilical cord artery.
Renate Ulmer, Institut fUr Humangenetik, Schwabachanlage 10, Erlangen, 91054,
Germany (phone +49-9131-85-2-4134; fax +49-9131-209297;
e-mail rulmer@humgenet.uni-erlangen.de)
PROTOCOL
Amniotic Fluid Cells - Uncultured
RENATE ULMER
Introduction
Cytogenetic analysis of fetal cells after amniocentesis is routinely offered
to women who have an increased risk of carrying a fetus with a chromosomal abnormality. Indications for fetal karyotyping include advanced
maternal age, increased risk for fetal trisomy by elements of the triple
screen (i.e. alphafetoprotein, human chorionic gonadotropin, and estriol),
a previous pregnancy with an aneuploid fetus or potential risks due to
family history.
The rate of chromosomal disorders in low-risk groups, like advanced
maternal age is about 2.0%. Rates of >20% of abnormalities are found in
high risk groups with pathological findings in ultrasonography (Eiben et
a1.1997, Claussen et al.1994).
Conventional prenatal diagnosis requires a long-term culture of amniocytes (6-14 days) and is routinely accomplished by GTG banding of
metaphase chromosomes. This technique is accurate and reliable, allowing the detection of a variety of numerical and structural aberrations. Disadvantages are the time-consuming cell-culture and the banding analysis
which requires some experience.
In certain clinical situations (sonographically detected severe fetal abnormalities) a result within the shortest time possible is urgently necessary
for the management of the pregnancy. In other cases, a rapid result could
moderate the anxiety of the pregnant woman, especially in cases such as
an advanced pregnancy, a pathological result of the triple screen, some
conspicuous sonographical findings like nuchal translucency, choroid
plexus cyst and singular umbilical cord artery.
Renate Ulmer, Institut fUr Humangenetik, Schwabachanlage 10, Erlangen, 91054,
Germany (phone +49-9131-85-2-4134; fax +49-9131-209297;
e-mail rulmer@humgenet.uni-erlangen.de)
PROTOCOL