NEXCCS
Your guide to aneuploidy screening
GROW I NG FAM I L I E S
What is comprehensive
chromosome screening?
Comprehensive chromosome screening (CCS), also
known as preimplantation genetic screening (PGS)
or aneuploidy screening, is designed to identify
which embryos have the greatest potential to
become a healthy pregnancy and baby.
Embryos with the normal number of chromosomes,
also called euploid embryos, have a greater chance
of becoming a healthy pregnancy and baby. Euploid
embryos have 46 chromosomes and are created
when a sperm with 23 chromosomes fertilizes an
egg with 23 chromosomes (see Fig. A). Sometimes
embryos are created that do not have the usual
number of chromosomes. These embryos, also
called aneuploid embryos, are more likely to result in
in vitro fertilization (IVF) failure.
By transferring only euploid embryos,
IVF teams and patients can improve
the chances of success with IVF.
Aneuploidy also contributes to miscarriage and
can be associated with health problems during
pregnancy or in the baby following delivery. One
of the most common examples of aneuploidy is
trisomy 21, also referred to as Down syndrome,
which is caused by the presence of a third copy of
chromosome 21.
Fig. A
Normal egg
with 23
chromosomes
“Family, like branches on a tree,
we all grow in different directions
yet our roots remain as one.”
– Unknown ­–
Normal sperm
with 23
chromosomes
Euploid embryo with
46 chromosomes
Comprehensive chromosomal screening using
NexCCS helps IVF teams and patients make
better decisions about which embryos should
be considered for IVF transfer based on their
chromosomal makeup.
How common is aneuploidy?
The chance for aneuploidy increases with maternal age and ranges from about 20% to greater than 90% at the
time of fertilization.
Approximate Percent of Embryos Which Are Aneuploid
100
90
80
70
60
50
40
30
20
10
0
22 23 24 25 26 27 28 29 30 31
32 33 34 35 36 37 38 39 40 41 42 43 44 45+
Maternal Age (yrs)
What is NexCCS?
Before the development of aneuploidy
screening, selecting embryos for IVF transfer
was based largely on how an embryo looked;
however, we now know that there is little
connection between how an embryo appears
on the outside and the number of chromosomes
present within.1 Current aneuploidy screening
through the FEC uses next-generation
sequencing (NGS)­—based comprehensive
chromosome screening. NexCCS has been
developed following extensive clinical trials
and counts all 23 pairs of chromosomes at the
molecular level for a comprehensive approach.
What type of sample is needed
for NexCCS?
To begin aneuploidy screening with NexCCS,
(see Fig. B) a sample is biopsied (safely removed)
from an embryo. The method of biopsy used in
NexCCS has been determined to be the safest
available. 2 Approximately 5 cells are removed
from a specific area of the embryo called the
trophectoderm at a specific time in embryonic
development. Unlike other methods of biopsy, a
trophectoderm biopsy has no significant impact
on the reproductive potential of the embryo and
therefore maximizes the benefit
of NexCCS. 2
Fig. B
NEXCCS P ROCESS
STEP 1
Perform trophectoderm biopsy
STEP 2
FEC receives embryo biopsy
STEP 3
FEC analyzes biopsy
STEP 4
Results made available to
your clinical team
Adding NexCCS testing to your
IVF plan will increase your
chances of a healthy pregnancy
without any delays in your care.
NexCCS allows for higher delivery
rates and safer pregnancies.
The biopsied cells are sent to the FEC, where they
are analyzed. A report is sent to your IVF team,
who will discuss the results of NexCCS with you.
Explore other tests at FEClabs.org
What happens to my embryos
during NexCCS?
What is the clinical impact of
segmental aneuploidy?
Your embryos never leave the care and security
of your team’s IVF laboratory. The NexCCS biopsy
process requires only a few cells, which are safely
removed and sent for analysis.
Segmental aneuploidy refers to a segment of
duplicated or deleted chromosome material
detected in an embryo biopsy. Although the
clinical significance of segmental aneuploidies
can vary, deletions and duplications are
associated with a significant risk of poor
outcome. If transferred, these embryos have
an approximate 50% reduction in the probability
of progressing to a live-born infant.
The patient coordinators and laboratory
technicians work closely with your IVF team to
coordinate the sending and receiving of biopsy
material. All required local, state, and national
regulations are followed closely to ensure the
safest and most effective handling of your samples.
NexCCS is at least 98.7%
accurate in screening for whole
chromosome aneuploidy. 3
What kinds of results could be
expected following NexCCS?
NexCCS is designed to detect whole chromosome
aneuploidy, meaning there is at least one additional
or missing chromosome, leaving an abnormal or
incorrect number. In addition, NexCCS also has
the ability to detect some cases of segmental
aneuploidy and mosaicism. Segmental aneuploidy
means that a piece (or segment) of extra or
missing chromosome material is detected in an
embryo. Mosaicism refers to a single embryo that
has a combination of cells with the usual number
of chromosomes (euploid) and cells with extra
or missing chromosomes (aneuploid). While the
clinical significance of both segmental aneuploidy
and mosaicism can vary, these findings increase
the risk for implantation failure, miscarriage, and
poor outcome.
What is the clinical impact
of mosaicism?
Mosaicism refers to a combination of euploid and
aneuploid cells in a single embryo. Embryo biopsies
in this category have at least one chromosome that
falls into a mosaic range. The risk for implantation
failure, miscarriage, and poor outcome is increased
in these embryos. Sustained implantation rates are
reduced by approximately half for embryos with
mosaic range results. If an embryo with mosaic
range results does implant, the risk for obstetrical/
neonatal complications or ongoing health issues is
not known. While a number of healthy infants have
been reported following PGS with mosaic results,
currently there is no long-term follow-up data.
How often is a result of segmental
aneuploidy or mosaicism expected?
Segmental abnormalities impact 5% to 10%
of all embryos. The presence of at least one
chromosome in a “mosaic range” in an otherwise
euploid embryo occurs in about 5% of samples.
How are results prioritized?
A normal result indicates that the usual number
of chromosomes was detected and that no
whole chromosome abnormalities, mosaicism,
or segmental aneuploidy was detected. These
embryos have the highest priority for transfer.
An abnormal result indicates that at least one
whole chromosome aneuploidy was detected
and the embryo should not be considered
for transfer. If the result indicates segmental
aneuploidy and/or mosaicism, the result is
categorized as aneuploid with undetermined
safety or reproductive potential. These results
are considered the lowest priority for transfer,
and genetic counseling is recommended to
review if transfer of one of these embryos is
being considered.
How long before results are
available?
NexCCS results will generally be ready about
a week after the FEC receives the biopsies. An
in-depth report is sent directly to your IVF team,
who will discuss the results of NexCCS with you.
What does NexCCS cost?
Speak with your IVF team about the costs and
benefits of NexCCS. Typically, genetic screening
of embryos for IVF is not covered by insurance
plans, and most patients will have to cover
some or all of the expense. Billing information is
required prior to the start of your cycle; however,
payment will not be processed until we receive
your samples for testing.
How accurate is NexCCS?
NexCCS is at least 98.7% accurate in screening
for whole chromosome aneuploidy, a dramatic
improvement over other forms of aneuploidy
testing.3 This means that in over 98 out of 100
cases, NexCCS will correctly predict the number
of chromosomes from the cells obtained in an
embryo biopsy. However, there is a low chance for
a false negative or false positive result. Therefore,
as with any test, it is important that you speak
to your physician to discuss the benefits and
limitations of this test.
Talk with your doctor or
genetic counselor to determine
if NexCCS is right for you.
References: 1. Forman EJ, Upham KM, Cheng M, et al. Comprehensive
chromosome screening alters traditional morphology-based embryo
selection: a prospective study of 100 consecutive cycles of planned fresh
euploid blastocyst transfer. Fertil Steril. 2013;100(3):718-724. 2. Scott RT Jr,
Upham KM, Forman EJ, Zhao T, Treff NR. Cleavage-stage biopsy significantly
impairs human embryonic implantation potential while blastocyst biopsy does
not: a randomized and paired clinical trial. Fertil Steril. 2013;100(3):624-630.
3. Data on file. The Foundation for Embryonic Competence. 2016.
ABOU T T H E F EC
The Foundation for Embryonic Competence (FEC)
is a nonprofit organization dedicated to advancing
knowledge and enhancing outcomes in embryonic
research, diagnosis, and education. NexCCS and
IdentifySGD are owned and operated by the FEC.
All proceeds from NexCCS and IdentifySGD
are used to support research and education.
See our story at FEClabs.org
140 Allen Road, Suite 300, Basking Ridge, NJ 07920
908.580.1200 • [email protected]
©2017 The Foundation for Embryonic Competence