3. SEMINAR ON GENETIC TESTING
PRESENTED BY:
M.C.KNIRANDA
1ST YEAR M.Sc.(N)
SNSR, SHARDA
UNIVERSITY.
4.
5. Genetic testing is "the analysis of chromosomes
(DNA), proteins, and certain metabolites in order
to detect heritable disease-related genotypes,
mutations, phenotypes, or karyotypes for clinical
purposes.” It can provide information about a
person's genes and chromosomes throughout life.
OR
Genetic testing is a broader sense includes tests
for the possible presence of genetic disease, or
mutant form of genes associated with increased
risk of developing genetic disorders.
OR
10. PRESYMPTOMATIC TESTING:-
It helps to identify a person who will develop a
genetic disorder such as hemochromatosis.
It can help to take preventive measures and making
decisions about medical care.
11. PREDISPOSITION TESTING:-
Genetic Predisposition - the tendency to develop a health
condition as a consequence of the interaction between
genetics and lifestyle factors.
This test is the key to taking control of the future of the
mother’s well being because her health could lie in her
genes.
With easy DNA’s genetic health testing service , a mother
can understand her health on a genetic level.
13. Definition:
Prenatal diagnosis is any of various diagnostic
techniques to determine whether a developing
fetus is affected with a genetic disorder or
other abnormality.
Diagnosis before birth.
14. Indications:
Prenatal diagnosis is recommended in the following
cases-
Parents have had a previous child with a chromosomal
abnormality.
The pregnant woman is 35 years or older at the time of
delivery
Mother has a history of recurrent abortions
Parental consanguinity
15. CONTD…..
The couple is known to be carriers of a chromosomal translocation.
The pregnant woman is affected with type 1 diabetes mellitus,
epilepsy
The pregnant woman is exposed to viral infections
The pregnant woman is exposed to excessive medication or to
environmental hazards
In parents family, a history of down syndrome or some other
chromosomal abnormality is present
17. THEY ARE AS FOLLOWS:-
1) Ultrasonography
2) Amniocentesis
3) Chorionic villus sampling (CVS)
4) Maternal blood sampling for fetal blood cells
5) Maternal serum alpha-fetoprotein (MSAFP)
6) Maternal serum beta HCG
7) Maternal serum estriol
8) Inhibin-A
9) Pregnancy associated plasma protein-A (PAPP-A)
10) “Triple” or “Quadruple” serum
18.
19. 1) ULTRASONOGRAPHY:-
This is a noninvasive procedure that is harmless to both the fetus
and the mother.
Major internal organs and extremities can best be visualized
between 16 and 20 weeks gestation.
Ultrasound examination can be quite useful to determine the size
and position of the fetus, the size and position of the placenta,
amount of amniotic fluid and appearance of fetal anatomy.
22. 2) AMNIOCENTESIS:-
This is an invasive procedure in which a needle is passed through the
mother’s lower abdomen into the amniotic cavity inside the uterus.
Amniocentesis can be done at about 14 weeks of gestation . For
prenatal diagnosis, most amniocentesis are perform between 14 and 20
weeks of gestation.
23. CONTD…..
Amniocentesis is useful to determine:
Gestational age
Position of fetus and placenta
Quantity of amniotic fluid
Chromosome analysis
Fetal lung maturity (3rd trimester)
Fluorescence polarization
24.
25. 3) CHORIONIC VILLUS SAMPLING:-
In this procedure, a catheter is passed via vagina through the cervix
and into the uterus to the developing placenta under ultrasound
guidance.
Introduction of the catheter allows sampling of cells from the
placental chorionic villi.
These cells can be analyzed by a variety of techniques and also be
grown in culture.
CVS can be done between 9.5 and 12.5 weeks gestation.
27. 4) MATERNAL BLOOD SAMPLING
FOR FETAL BLOOD CELLS:-
This is a new technique that makes use of the phenomenon of fetal
blood cells gaining access to maternal circulation through the
placental villi.
The fetal cells can be sorted out and analyzed by a variety of
techniques to look for particular DNA sequences.
Flourescence in-situ hybridization (FISH) is one technique that can
be applied to identify particular chromosomes of the fetal cells
recovered from maternal blood and diagnose aneuploid condition
such as trisomies and monosomy.
28.
29. 5) MATERNAL SERUM ALPHA-
FETOPROTEIN TEST:-
The developing fetus has two major blood proteins albumin and
alpha fetoprotein .
MSAFP is a careening test that examines the level of alpha-
fetoprotein in the mother’s blood during pregnancy.
Blood is drawn from veins in the mother’s arm and sent off to a
laboratory for analysis.
MSAFP may be performed between the 14th and 22nd weeks of
pregnancy
30. CONTD…..
MSAFP test can be done to determine-
Levels of alpha fetoprotein of fetus.
Neural tube defect
Gestationl age
Abdominal wall defect
31.
32. 6) MATERNAL SERUM BETA HCG:-
The test is most commonly used as a test for pregnancy.
About a week following conception and implantation of the
developing embryo in to the uterus, the trophoblast will
produce enough beta HCG to diagnose pregnancy .
In the later pregnancy beta HCG can be used to determine -
Chromosomal abnormalities
Down syndrome
Molar pregnancy, hydatiform mole
33. 7) MATERNAL SERUM ESTRIOL:-
The amount of estriol in maternal serum is dependant
upon a viable fetus, placenta and maternal well being.
Maternal serum estriol can be useful in determination of
General well-being of fetus
Down syndrome
34. 8) INHIBIN-A:-
Inhibin is secreted by the placenta and corpus luteum.
Inhibin-A can be measured in maternal serum.
An increased level of inhibin-A is associated with an increased risk
for trisomy 21.
A high inhibin-A may be associated with a risk for preterm delivery.
35. 9) PREGNANCY ASSOCIATED
PLASMA PROTEIN-A (PAPP-A):-
Pregnancy-associated plasma protein A (PAPP-A) is an important
pregnancy protein.
Low level of PAPP-A as measured in maternal serum during the
first trimester may be associated and fetal chromosomal anomalies
including trisomies, 13, 18, 21.
Low PAPP-A levels in the first trimester may predict and adverse
pregnancy outcome including a small for gestational age or still
birth.
36. 10) “TRIPLE” OR “QUADRUPLE”
SCREEN:-
The triple screening measures the amounts of three
substances in a pregnant woman's blood: alpha-
fetoprotein (AFP), human chorionic gonadotropin
(hCG), and estriol (uE3).
When a test for the hormone inhibin A is added, it's
called a quad screening.
