easy to understand

1. PRESENTED BY,
PRAKRUTHI

2. Genetic testing is a type of medical test that identifies
changes in genes, chromosomes, or proteins.
 The results of a genetic test can confirm or rule out a
suspected genetic condition or help determine a person’s
chance of developing or passing on a genetic disorder.
 Many genetic diseases can be diagnosed by a careful
clinical history and examination of patient who has or is
suspected to have a genetic disease.
 Recent advances in medical genetics has made it possible
to diagnose many of the genetic disorders when fetus is
inside the uterus itself.
GENETIC TESTING

3. Genetic testing is defined as “examining a sample of blood or other
body fluids or tissue for bio-chemical chromosomal, or genetic
markers that indicate the presence or absence of genetic
disease.
GENETIC TESTING
Genetic testing is voluntary and it has both benefits and
limitations. Genetic testing is different from the other tests
done in clinical practice.
Genetic test of the patient may also provide results for family
members. It may open up ethical or psychological problems.
Genetic counseling is important before advising for any test with
genetic implications.

4. Testing to confirm a clinical diagnosis:
When a genetic disorder is suspected on physical
characteristics or symptoms, genetic tests are required for
either confirmation of genetic disease or to rule out a
suspected genetic disorder.
Carrier testing/screening: Carrier of particular genetic
disorder is an unaffected individual who carries one copy of
a mutated disease. Carrier testing is done in unaffected gene
for a individuals who have a family history of a genetic
disorder.
Predictive and Pre-symptomatic testing: Pre-symptomatic
testing is most commonly done for individuals, who have a
family member with a genetic disorder, but are not having
features of the disorder themselves at the time of testing..

5. Genetic testing before a pregnancy is ideal, because
this provides the wide range of choices if an increased
risk of a deleterious genetic condition is detected.
 Most of the genetic tests are done after the woman
becomes pregnant.
 Depending on the time of performing, these genetic
tests, they can be divided into four types.
 Preimplantation: Before conception (i.e. when one or
two of the parents are carriers of a certain trait).
Prenatal testing: These are done after conception.
Newborn or neonatal, childhood screening.
Screening tests in adolescence and adulthood.

6. It is also known as embryo screening. It is performed
to detect genetic changes in embryos prior to the
implantation.
This can reduce the risk of having a child with a
particular genetic or chromosomal disorder.
The human embryos can be produced using
assisted reproductive techniques such as in-vitro
fertilization (IVF).
In vitro fertilization involves removing egg cells
from a woman's ovaries and fertilizing them with
sperms outside the body.

7. for fertilization (IVF):
Oocytes are collected from mother's ovary by
ultrasound guided technique.
Oocyte is fertilized by husband's sperm by puncturing
the oocyte. This is known as intracytoplasmic sperm
injection (ICSI).
The fertilized oocyte is cultured to grow up to 8-10
cell blastocyst stage. One cell is removed from this
early embryo and the DNA is extracted from the cell.
DNA or chromosomal analysis is performed for any
genetic abnormalities.
The embryo is implanted into the mother's uterus only
if it is healthy and free of genetic defects/errors.

8.  Prenatal diagnostic genetic analysis tests are
performed on fetus or embryo before it is born
to detect changes in a fetus's genes or
chromosomes.
 The couples with an increased risk of having a
baby with a genetic or chromosomal disorder
are usually offered this type of testing during
pregnancy.
 Newborn and Child Screening: It is used to
identify genetic disorders just after birth, so
that it can be treated early in life.

9. Newborn and childhood genetic analysis
NEWBORN WITH :
Major birth defects
Unusual (dysmorphic) facial features
Suspicion of a metabolic disorder (e.g. phenylketonuria)
Positive newborn screening test
Congenital hypothyroidism
Suspected aneuploidy (e.g. features of Down syndrome)
unbalanced autosome (e.g. Prader-Willi syndrome)
sex chromosomal abnormality (e.g. Turner syndrome)
fragile-X syndrome
CHILD WITH :
Developmental delay and/or unexplained mental retardation
Unusually tall or short stature, or growth delays
Chromosomal abnormality

10. A mother of advanced age (>35 years) who has increased risk of trisomy’s .
A parent
Already having child with a chromosomal abnormality or birth defect or family history of
birth defects
who is a carrier of a translocation (balanced reciprocal or Robertsonian) or inversion
who is a carrier of an X-linked genetic disorder
Family History of
Chromosomal abnormality
Single-gene disorder
Neural tube defects
Congenital structural abnormalities
Mental retardation
A fetus with abnormalities detected by ultrasound
A genetic disorder for which there is no satisfactory treatment
Abnormal levels of AFP, BHCG, and estriol performed as quadruplet /triple test
Parental consanguinity
Recurrent spontaneous abortions/miscarriages
Previous unexplained stillbirth Intake of certain medications or teratogens during
pregnancy
Maternal conditions such as diabetes, epilepsy, or alcoholism

11. The placenta, fetus and amniotic fluid are located with the help of the ultrasound.
With or without local anesthesia a thin, hollow needle (22 gauge with a stylet) is
inserted into the uterus through the abdomen.
When the needle enters the amniotic sac patient may feel a sharp pain for few
seconds.
About 10-20 mL of the amniotic fluid is aspirated. The fluid is normally clear and
yellow.
Remove the needle and apply bandage at the skin puncture site. Monitor the fetal
activity by ultrasound.
The amniotic fluid is centrifuged to separate the cells. The cells are then cultured
for further karyotyping studies and DNA studies.
The fluid is subjected to various biochemical tests for the detection of substances like
the a-fetoprotein, carcinoembryonic antigen and others.

12. It is an invasive technique in which a piece of
chorionic villus material of placenta is obtained.
It is generally performed between 10 and 12 weeks
of pregnancy.
It is done either trans cervically with a flexible
catheter passing through the vagina and cervix into the
uterus or by a needle inserted through the abdomen
(transabdominal puncture).
Both the methods are performed under ultrasound
guidance, and piece of developing placenta are
obtained.
The viability of fetus is checked before and after
the procedure.
Indications: It is indicated for the diagnosis of chromosomal disorders or various
genetic conditions by DNA analysis.
Advantages It can be performed during much earlier weeks of gestation than the
amniocentesis. Results are usually ready within 1-2 weeks which permit earlier
termination of pregnancy, if required. Earlier termination of pregnancy is safer than
late pregnancy. More cells for study are obtained than amniocentesis.
Disadvantages CVS is not routinely done because it carries a risk of miscarriage and
other complications.

13. A non-invasive and harmless procedure.
In this method, high frequency sound waves
echo back from tissue interfaces, organs
including the baby in the amniotic cavity and a
picture is obtained.
During pregnancy, it is usually used to
confirm that pregnancy is viable, assess
gestational age, localize the placenta, assess
amniotic fluid volume and monitor fetal
growth.
Ultrasonography is required during
amniocentesis, chorionic villus sampling and
fetal blood sampling, and it provides
evaluation of fetal anatomy during the second
and third trimesters.

14. The blood from umbilical vein is
obtained by passing a fine needle through
the mother's abdomen into the umbilical
vein in the umbilical cord.
The fetal blood obtained, is subjected to
genetic testing.
This procedure can be used for
intrauterine blood transfusions and
administration of drugs directly into the
fetus.

15. visualization of the fetus in the uterus
by a fiberoptic self-illuminated
instrument.
The fiberoptic scope is inserted into
the amniotic cavity under local
anesthesia.
Fetoscopy is usually performed
between 18-22 weeks of gestation.

16. Normally, few fetal blood cells enter the maternal circulation through
the chorionic villa of the placenta.The fetal cells from maternal
blood can be separated and analyzed for particular DNA sequence.
Fluorescence in situ hybridization (FISH) is one of the techniques in
which fetal cells can be analyzed for conditions such as trisomy and
monosomy X.
The disadvantage of this technique is that maternal blood may contain
only few fetal cells.
Measurement of maternal serum for four bio chemical substances namely
a-fetoprotein (AFP), human chorionic gonadotropin (HCG),
unconjugated estriol (uE3) and inhibin A (INH-A) is known as
quadruple screen test.
Formerly AFP, hCG and estriol tests were known as triple screen test.
This is a non-invasive test and is usually done in the second trimester
(between the 15 and 20 weeks) of pregnancy.
It is not a diagnostic test. Positive test may only suggest that a mother is
at a possible risk of carrying a fetus with a genetic disorder.
More invasive but more accurate tests are amniocentesis and chorionic
villous sampling.

17.  Inhibin-A is elevated in the blood serum of women carrying fetuses with Down
syndrome.
 Low levels of AFP and abnormal levels of hCG and estriol may indicate that
the developing fetus has trisomy 21 (Down syndrome), trisomy 18 (Edwards
syndrome) or other chromosome abnormality.
 A raised AFP level indicates the need for further investigation by
amniocentesis or ultrasound scanning.
 Estimation of maternal serum a-fetoprotein (AFP) concentration in the second
trimester is valuable screening test for neural tube defects such as spina bifida
or anencephaly.
INDICATION FOR QUADRUPLE
 Women aged 35 years or more
 Women who had a viral infection during pregnancy
 Women exposed to high levels of radiation
 Women with diabetes and on insulin
 Who has taken harmful medications or drugs during pregnancy
 With a family history of birth defects