By
ARACELI FLORES SURAT,MAN
NCM 109 INSTRUCTOR
⚫Genetics- a branch of biology concerned
with the study of genes, genetic variations
and heredity in living organism.
⚫Genetic counselling- is a process of
communicating between two or more persons
who meet to solve a problem, resource a
curse or take decisions on various matters.
It is not a one way process where in the
counseling tells the client what to do nor it
is a forum for presentation of the
counselor’s value
⚫Is the process of advising individuals and
families affected by or at risk of genetic
disorders to help them understand and adapt
to the medical, psychological and familial
implications of genetic contributions to
disease
other terms:
⚫Phenotype – refers to outward appearance
of the expression of genes
⚫Genotype – refers to actual gene
composition
⚫Genome – complete set of genes present
⚫ Normal genome ; 46XX/46XY
⚫Genetic disorders – disorder passed from
one generation to the next
⚫Occur in same ethnic group
⚫Occur at the moment an ovum and sperm
fuse or even earlier in the meiotic division
phase of the ovum or sperm when the
chromosome count is halved from 46 to 23.
Methods of Assessment
A. History Taking
✔ Include any one related to the family
✔ Maternal age (> 35 y/o)
✔ Paternal age (>55y/o)
✔ Document parents if consanguineous/related
to each other
✔ Document ethnic background
✔ Extensive prenatal history
B. Physical assessment
• Pay particular attention to the space
between the eyes, height, contour, shape oe
ears, number of fingers and toes, presence
of webbing(syndactyly)
⚫DERMATOGLYPHICS – study of surface
markings of the skin
:
Down syndrome/Trisomy 211
Code: 47XXY21/47 XY21
Characteristics
Late closure of fontanelle
Slant eyes
Epicanthal fold (extra fold of tissue
at the inner cannula )
Brush field spots ( iris with white
specks)
Large tongue
Low set ears
Small mouth cavity
Back of the head is flat
Neck is short
Extra pad of fat at the base of the
head causes the skin to loose
Poor muscle tone ( rag-doll
appearance)
Fingers are short and thick
Little finger is often curved inward
Wide space between the 1st and 2nd
finger and toes
Palm- with one single horizontal
simian crease
Small head
Brain is not well developed
IQ= 50-70
Prone for infection
Clinodactyly
Abnormal dermatoglyphics
Trisomy 18 / Edward’s syndrome
Code: 47XY18/47XX18
Characteristics
have copies of chromosome 18
- do not survive beyond early
infancy.
Microcephaly
Severely cognitively challenges
SGA at birth
Marked low set ears
Small jaw
Congenital heart defects
Misshapen fingers and toes (index
fingers deviates or cross over other
finger)
Multiple hair whorls
Fragile X syndrome
(Code: 46XY23q)
Characteristics
Most common cause of cognitive
challenge in males
-An X linked disorder in which 1
long arm of an X chromosome is
defective
- before puberty: displays
maladaptive behavior such as
hyperactivity and autism
Bossing (prominent forehead)
Prominent lower jaw
Large hands
Marked deficit in speech and
mathematics/problem solving
Large head
Long face
Large protruding ears
After puberty: enlarged testicles
Turner syndrome
Code: 45X0
characteristics
Has only 1 functional X chromosome
Low set hair line
Webbed neck
Can be identified with an UTz during Gonadal diagenesis
pregnancy because of the increase
Short in structure
neck folds.
Has only streak (small and
nonfunctional) ovaries
Sterile
Exception of pubic hair; secondary
sex characteristics do not develop
at puberty
Newborns= edema on the hands and
feet
With coarctation (stricture) of
aorta and kidney disorder
Severely cognitively challenge
Klinefelter syndrome
Code: 47XXY
characteristics
Males
With an extra X chromosome
Absence of secondary sex
characteristics
Small testes- produces ineffective
sperm
Gynecomastia ( enlarged breast
size)
Increased risk of male breast
cancer
Trisomy 13/ patau syndrome
Code: 47 XX13/47 XY13
Characteristics
Has an extra chromosome 13 and
cognitively challenged
Most do not survive beyond early
childhood
Microcephaly
Clip lip and palate
Low set ears
Multiple hair whorls
Wide set nipples
Rocker bottom feet
Heart defects ( ventricular septal
defect)
Abnormal genitalia
Small eyes (microphthalmus)
C. Diagnostic testing
Karyotyping
sample of peripheral venous blood or
a scraping of cells from the buccal
membrane is taken
Cells are allowed to grow until they
reach metaphase- most easily
observed phase
Cells are stained, placed under a
microscope and photographed
Chromosomes are identified
according to size, shape and stain
is a test to identify and evaluate
the size, shape, and number of
chromosomes in a sample of body
cells.
Maternal serum screening
Done at 15th week of pregnancy
Alpha-fetoprotein (AFP)- a
glucoprotein produced by the fetal
liver
Peak is between 13th and 32nd week
of pregnancy
RESULT: if elevated – it means
spinal cord disease/ neural tube
defects
If below – it means chromosomal
disorder/Down syndrome
MSAFP (Maternal Serum Alphafetoprotein)
CVS (Chorionic Villi Sampling)
– a diagnostic techniques that
involves the retival and analysis of
chorionic villi from the growing
placenta for chromosome or DNA
analysis
Commonly done at 8-10 weeks or 1012 weeks of pregnancy.
May be done as early as 5 weeks.
is a prenatal test in which a sample
of chorionic villi is removed from
the placenta for testing. The sample
can be taken through the cervix
(transcervical) or the abdominal wall
(transabdominal).
Amniocentesis
withdrawal of amniotic fluid through
the abdominal wall for analysis
Done between 14th-16th week of
pregnancy.
A pocket of amniotic fluid is located
by ultrasound (UTZ)
A needle is inserted trans
abdominally
Aspirate 20 ml of amniotic fluid
Client receives Rh immune globulin
administration after the procedure
(Rhogam)
PUBS (Percutaneous Umbilical Blood
Sampling)
Other name: Cordocentesis
Removal of blood from the fetal
umbilical cord at about 17 weeks
using an amniocentesis technique
Fetal Imaging
MRI and UTZ = used to assess a
fetus for general size and structure
disorder of the internal organs,
spine and limbs
GENETIC COUNSELING
⚫ Provide concrete, accurate information about the
process of inheritance and inherited disorder
⚫ Reassure people who are concerned that their child
may inherit a particular disorder that the disorder
will not occur
⚫ Allow people who are affected by inherited disorder
to make informed choices about future reproduction
⚫ Offer support on people who are affected by
genetic disorder
⚫ observe data privacy.
⚫ ideal time for counseling is before 1st pregnancy
ROLE OF A NURSE IN
GENETIC COUNSELING
⚫Guiding women or couple through prenatal diagnosis
⚫Helping parents to make decisions in regards to
abnormal prenatal diagnosis results
⚫Assisting parents whi have a child with a birth
defect to locate needed service and support
⚫Providing support to help the family deal with the
emotional impact of a birth defect
⚫Coordinate services of other professionals such as
social workers, physical and occupational
therapists, psychologist, dietatcian
Importance of genetic
counselling
1. Aid in determining the risk of disease
2. Help in identifying a hereditary condition
3. Assist in whether genetic testing is
appropriate
4. Offer diagnoses and disease prevention
and management
5. Offer emotional and psychological support,
ethical guidance to help clients make well
informed autonomous health care decisions
and reproductive choices