Genetics is the branch of science that deals with the study of heredity Term ‘Gene’ was coined in by Johannsen in 1909 Mr. Johann Gregor Mendel(1822-1884) is “Father of Genetics”

1. Genetic Testing

2. Introduction
• Genetics is the branch of science that deals with
the study of heredity
• Term ‘Gene’ was coined in by Johannsen in 1909
• Mr. Johann Gregor Mendel(1822-1884) is “Father of
Genetics”

3. Definition
• Genetic testing is defined as “examining a
sample of blood or other body fluids or
tissues for biochemical chromosomal or genetic
markers that indicate the presence or absence
of disease.”
• A genetic testing is analyzing a DNA to look
for genetic alteration that may indicate an
increased risk for developing a specific
disease or disorder.

4. Purposes of genetic testing
• Confirmational diagnosis of a symptomatic
individual
• Forensic or identity testing
• Pre-symptomatic testing
• It allows the genetic disorder of
vulnerability to inherited disease
• Finding possible genetic disease in newborn
babies
• Screening embryos for disease

5. Benefits of genetic testing
• There are certain cancer markers, for example
CA125. These can be diagnosed in early phase and
can help in reducing the mortality and morbidity
rate due to genetic disorder.
• Next generation can be prevented if early
diagnosed.

6. Indications
• Maternal :
• Advanced age
• Previous child with genetic disorder
• History of miscarriage
• Some carrier states

7. • Prenatal
• AFP abnormal value
• Exposure to certain medications
• Oligohydramnios
• Polyhydramnios
• Some abnormalities in the genetic test
• Abnormal USG

8. • Paediatric
• MR
• Some other disease such as Cystic fibrosis
• Adult
• Miscarriages
• Some cancer markers in the blood

9. Genetic testing techniques
• Can be done by two types:
1. Molecular genetic testing
2. Chemical genetic testing

10. 1. Molecular genetic testing:
• DNA testing: ex: hemophilia, huntington disease
• Linkage testing: ex: PCKD, neurofibromatosis
• Methylation studies: ex: Rett syndrome
• Protein truncation test: ex: breast cancer
• FISH(fluorescent in situ hybridization: ex:
angelma’s syndrome, william syndrome
• PCR

11. 2. Chemical genetic testing
• Analyte testing: assess the presence of
substance in the body indicative of genetic
disorder. Ex: Hemocysteinuria
• Enzyme assay: ex: Galactosemia, Gaucher’s
disease
• Protein analysis: test for structure of
proteins known to be associated with genetic
disorders. Ex: marfan syndrome

12. Types of genetic testing
• PRE-IMPLANTATION GENETIC SCREENING
• PRENATAL GENETIC SCREENING
• NEONATAL GENETIC SCREENING
• FAMILY GENETIC SCREENING
• POPULATION GENETIC SCREENING
• FORENSIC TESTING
• CARRIER TESTING
• DNA TESTING

13. 1. PREIMPLANTATION GENETIC
SCREENING
• It is a technique that can reduce the risk of
having a child with a particular genetic or
chromosomal disorder.
• It is used to detect genetic changes in embryos
that were created using assisted reproductive
techniques such as in vitro fertilization

14. 2. PRENATAL GENETIC
SCREENING
• This is used to detect changes in a fetus’s genes
or chromosomes before birth. This type of testing
is offered during pregnancy if there is an
increased risk that the baby will have a
chromosomal or genetic disorder

15. Indication for prenatal
genetic analysis
• Advanced maternal age
• Family history
• Previous child with genetic disorder
• Family history of NTD

16. Approaches for the prenatal
genetic screening
• Amniocentesis
• CVS(chorionic villi sampling)
• USG
• Cordocentesis(PUBS)
• Maternal serum AFP

17. Amniocentesis
• Done at 14-18 weeks of gestation
• It is an invasive transabdominal procedure done
to take sample from the amniotic fluid
• Done under ultrasound guidance.
• Total sample taken is about 20-30 ml.

19. Role of nurse in amniocentesis
• Explain the procedure to the client
• Take informed consent from the mother
• Explain about various complications that may
arise after and during the procedure.
• Reduce the anxiety of the client.
• Inform about the follow up and test result
availability

20. Chorionic Villi sampling (CVS)
• It is an invasive transabdominal or
transcervical procedure of taking the sample
from the chorionic villi masses for the
purpose of prenatal diagnostic purpose.
• Done at 11 to 12 weeks of gestation.

23. Nursing role for CVS
• Take informed consent from the mother
• Reduce the anxiety of the client.
• Inform about the follow up and test result
availability
• Monitor for any sign of infection and ask the
patient to report immediately if any ususual seen

24. Ultrasonography (USG)
• Ultrasonography is the use of medical
ultrasonography in pregnancy, in which sound
waves are used to create real-time visual images
of the developing embryo or fetus in its mother's
uterus (womb).
• It is done at 16 to 18 weeks.

26. Role of nurse in USG
• Explain the procedure to the client
• No special preparation is needed
• Ask the client to drink enough amount of water
and try not to urinate before USG
• Clear the doubts of the client
• Counsel the couple about regular follow ups and
medicines during pregnancy

27. Cordocentesis or Percutaneous
umbilical blood sampling (PUBS)
• Cordocentesis is a diagnostic genetic test that
examines blood from the fetal umbilical cord to
detect fetal abnormalities.

29. Maternal serum screening
• Maternal Serum Screening is a blood test
offered to pregnant women who want to find out
if they may be at increased risk of having a
baby with Down syndrome, trisomy 18 or neural
tube defects (such as spina bifida).

30. • Between 15 and 21 weeks' gestation, a maternal
serum sample is screened for alpha-fetoprotein
(AFP), estriol and human chorionic
gonadotropin (HCG).

31. Alpha feto protein(AFP)
• AFP is a substance made in the liver of an unborn
baby (fetus).
• Increased in NTD
• Decreased in Down’s syndrome.

32. 3. NEONATAL GENETIC SCREENING
• Newborn screening tests help to identify
potentially treatable or manageable congenital
disorders within days of birth
• Life-threatening health problems, mental
retardation, and serious lifelong disabilities
can be avoided or minimized if a condition is
quickly identified and treated.

33. Uses
• Can be done for screening of:
• 1. Galactosemia
• 2. Phenylketonuria
• 3. Congenital hypothyroidism
• 4. Sickle cell disease etc.

34. 4. FAMILY GENETIC SCREENING
• Can be done in a family having high risk for the
genetic disorder.
• It can be done for various diseases such as
cystic fibrosis, Huntington’s disease,
Hemochromatosis etc.

35. 5. POPULATION SCREENING
• Can be done on a population where genetic
disorders are very common. Such as Sickle cell
disease in black africans and carribeans
• They can be given special services of genetics
such as:
• Couple counselling
• Individual counselling

36. Other tests for expecting
mother
• Quadruple test:
• MSAFP
• Estriol
• hCG
• Inhibin A
• PAPP-A
• USG

37. 6. Forensic testing
• Identifies an individual for legal purposes
• Can be used to identify crime or to establish
biological relationship between people ex:
paternity

38. 7. Carrier testing
• Completed on asymptopmatic individuals who may be
carrier of one copy of a gene alteration in x
linked pattern of inheritence

39. 8. RESEARCH TESTING
• It includes finding unknown genes, learning
how gees work and advancing our understanding
of genetic conditions.
• The result of testing done as a part of a
research study are usually not available to
the patients or their health providers. For
example: HIV resistant gene

40. Limitations of genetic testing
• It is never 100% accurate
• It cannot detect the presence of a disease. For
example: genetic test for hereditary breast
cancer cannot predict who will get the disease
• Cannot detect all the mutation causing the
disease

41. • It can lead to ethical and social consideration
such as survivor guilt, confidentiality, person
not wishing to share the disease condition,
maintaining anonymity
• Genetic discrimination among employees

42. Current updates in genetic
testing
• New research study on Proteomics state that we
can now detect “ZIKA” virus with saliva test
which can decrease the chance of baby born with
“microcephaly”
• HIV resistant gene is ready to be used for
treatment therapy.
• Angelina Jolie’s treatment therapy

43. Role of nurse in Genetic testing
• The nurses are responsible for alerting clients
of their rights to make an informed decisions
prior to any genetic testing
• All genetic testing should be voluntary and it is
the nurse’s responsibility to ensure that the
consent procedure include discussion of the risk
and benefit of the test.
•

44. • Nurses need to ensure client’s confidentiality
and privacy of genetic testing
• Nurses should address psychological, social
and economic issues of person and family
undergoing for genetic testing
• Take informed written consent from the patient

45. • Administer prophylactic antibiotics in
invasive tests as per institutions policy
• Offer counseling services as per need of the
patient and family
• Inform about follow up and test result
availability

46. Conclusion and Summary