Nursing

1. Introduction to Genetics
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2. Concept of genetics
• The term Genetics was introduced by
Bateson in 1996.
• Derived from Greek word ‘ gene ‘ which
means ‘to become’ or ‘to grow into’
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3. Definition
• Genetics is the branch of biological
sciences which deals with the
transmission of characteristics from
parents to offspring.
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4. Practical application of genetics in
nursing
Application of genetics in nursing is very wide
since:
• All nurses have a role in delivery of genetics
services
• Nurses required genetic knowledge to
identify, support, refer and care for
persons affected with genetics disorder.
• Nurses can offer care that protects
patients & families from the risk associated
with genetic information.
•
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5. • Nurses are also needed to refer patients to
genetic specialist and assist in making choice of
genetic health care.
• Genetics nursing is practiced in different
environment such as maternity, paediatrics,
medical surgical nursing.
• Genetics nursing is holistic practice that
assessing, planning, implementing & evaluating the
physical aspects of patients & families.
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6. Major practical application of genetics in
nursing
1. Understand the genetics basis of diseases.
2. Early & effective diagnosis of genetics
disorders.
3. Contributes towards health promotion with
genetics aspects.
4. Prevention of genetics conditions
5. Management in genetics disorders
6. Genetics information & counselling
7. Referral services
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7. 7
Impact
of
genetics
condition
on
families
Social
impact
Psychological
impact
Economic
impact
Physical
cognitive
impact

8. Factors influencing the impact of genetics conditions
on families
1. The size, structure & stage of the family
2. Religions , ethnic & culture beliefs
3. Availability of relationships with extended family
members or close friends
4. The prior status of the relationship between
parents
5. Severity of the disorders
6. Variable relating to individual family
members.
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9. Role of nurse in managing the impact
 Recognize that different people cope with shock in
different ways.
 Build a trusting environment
 respect the parents feeling
 Build family strength
 Taught the special care procedure, such as moving the
child with osteogenesis imperfecta or feeding the cleft
palate child.
 Helps in decision making
 Observe the interaction of parents with child, family
 Help the parents to maintain communication
 Ascertain the support system
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10.  Contact patients groups of persons with
similar affected children
 Work with patients to plan a time table
 Give opportunities to ask questions.
 Refer to the advanced care facilities
 Helps the family to rebuild self esteem
 Follow up care
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11. Characteristics
& structure
of genes
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12. • The term genes was introduced by
Johanssen in 1990.
• Gene is defined as a unit of inheritance
composed of segment of DNA or
chromosomes situated at specific locus
which carries coded information associated
with specific function & undergo crossing
over as well as mutation
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13. • A gene is a basic unit of heredity. It
is made up of certain sequence of
DNA and RNA. Gene occupy a fixed
position on the chromosome and
helps the body by directing the
synthesis and formation of chemical
compounds of protein

14. GENES
• It is a basic physical and functional unit
of heredity
• It is carried from parents by a gamete in
a chromosome and controls the
expression of a character in the young
ones in co-operation with its allele gene
and environment
• Purpose for Genes is to code for making a
specific protein used by a cell,tissues or
organ within a person.

15. • Human being have between 20,000 and
25,000 genes (Human Genome Project)
• Every person has 2 copies of each gene, one
inherited from each parents
• Most genes are same in all people except small
number of gene (less than 1 %) and these
small differences contribute to each persons
unique physical feature.

17. Types of genes
• Constitutive gene : those gene which are constantly
expressing themselves in a cell.
• Non constitutive (luxury) gene: not always expressing
• Inducible gene: the gene are switched on in response
to the presence of chemical substance ( inducer)
• Repressive gene : continue to express themselves till
a chemical inhibits their activity
• Repeated genes : the gene present in multiple copies,
e.g tRNA genes, rRNA genes
• Single copy gene: present in single copy
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18. • Pseudogenes : unable to produce functional
products.
• Split genes: which possess extra or non
essential region
• Jumping genes: that can jump or move from one
place to another
• Overlapping genes: gene that overlap
• Structural genes: which have encoded
information for the synthesis of chemical
substances for cellular activity
• Regulatory genes: that control the function of
structural gene
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19. DNA: Deoxyribonucleic
Acid
• Quantity: The DNA content is fairly
constant in all the cells of a given
species. Just before cell division,
the amount of DNA is doubled. The
gametes have half the amount of
DNA as they contain half the
number of chromosomes.

20. Chemical Structure
• largest macromolecule
• long double chain of deoxyribonucleotide units
• right-handed double helix (spiral)
• Phosphate, a 5-Carbon deoxyribose sugar and a
Nitrogenous base
• Adenine (A) or Guanine (G)
• Thymine (T) or Cytosine (C)
• nitrogenous base molecules are joined to sugar
molecule at 1-Carbon position by glycoside
bonds
• two deoxyribonucleotide chains are held
together by hydrogen bonds.

23. Some Important Points Regarding DNA
• Human DNA is double stranded helical structure
comprised of four different bases, the sequence of
which codes for the assembly of amino acids to make
a protein e.g. an enzyme. These proteins are
important for following reasons:
– For body characteristics such as eye color.
– For biochemical processes such as the gene for
the enzyme that digests phenylalanine.
– For body structure such as chromosome collagen
gene important for bone formation.
– For cellular functioning such as genes associated
with cell cycle.

24. The four DNA bases are Adenine, Guanine,
Cytosine, Thymine or AGTC.
• A change, or mutation, in the coding sequence,
such as duplicated or deleted region or even a
change in only one base, can alter the production
or functioning of the gene or gene product, thus
affecting cellular processes, growth &
development.
• DNA analysis can be done on almost any body
tissue (blood, muscle, skin) using molecular
techniques (not visible under microscope) for
mutation analysis of a specific gene with a known
sequence for DNA linkage of genetic markers
associated with a particular gene.

26. CHROMOSOME
• Chrome=colour, Soma=body (Weldeyer in
1888)
• It points to the fact that chromosome
easily takes up biological stains
• Capable of replication (production of
exact copies of chromosome)
• They store and transmit coded
information about biological activities

27. STRUCTURE OF
CHROMOSOME

28. Anatomy of a Chromosome
• Centromere - point
where sister
chromatids are
joined together
• P=short arm;
upward
• Q=long arm;
downward
• Telomere-tips of
chromosome
p -arm
centromere
q-arm
telomere
chromatids

30. SEX
CHROMOSOME
• In human 46 chromosome occurs in
pair except oocytes and sperm which
each contains only 23 chromosomes
• 22 pairs of chromosome
(autosomes)are same in males and
females
• The 23rd pair is referred as the sex
chromosomes

31. Contd…
• Females have XX chromosome and
male has XY chromosome
• At conception each parents normally
gives one chromosome of each pair to
his or her children
• Children receive half of their
chromosome from their father and
half from mother

32. Chromosomal abnormalities
Down syndrome (trisomy 21)
• It is caused by having 3 copies or extra
part of chromosome 21.
• Characteristics are mild to moderate
learning disabilities
• Mental retardation(50-60%)
• G.I obstruction,ASD,VSD,Leukemia
• Severe hypotonia,brachycephaly
• Single palmer creases(50%)

33. Klinefelter syndrome
• It results from extra X in male .
• They have a genotype of 47(XXY)
instead of XY genotype.
Characteristics
• Shy, sterile,
• Higher incidence of dyslexia and
speech problem
• Enlarged breast, small testes

34. Turner syndrome
• Individual have only one X chromosome
• Characteristics
• Phonemically female but will be sterile
due to underdeveloped ovaries.
• Triangle shape face
• Webbing of the neck
• Short stature
(Majority of them lead
a normal and healthy life)

35. Cridu chat Syndrome
• A disorder caused from deletion of
short arm of chromosome
• Characteristics
- Mental retardation
-respiratory distress/obstruction
- cat like call or cry
(1/50,000 will have this syndrome.
Brunner)

36. Di George syndrome
• Results from a micro deletion of part
of chromosome 22.
Problems are
• Heart malformation
• Failure of parathyroid to develop
• Schizophrenia like episode in adult
life
(Turpenny and Ellard,2007)

37. Huntington’s Disease
• Disorder of mutation in chromosome
4 which codes for a protein called
Huntinton
• Autosomal dominant trait therefore
an affected parents have 50%
chance of having an affected child.
• Characteristics
-Early signs include clumsiness,lack of
concentration, memory lapses
- Huntinton,s chorea(jerky and
uncontrolled movement)

38. MUTATION
• It is a permanent change in the DNA
base sequence that makes up a gene
• They are capable of changing the
phenotype of an individual.
• Cells depends on thousand of protein to
functions correctly. A mutation that
alters a protein which plays a very
important role in the body can result in a
medical conditions such as
• cancer,leukemia etc

39. • The DNA sequence can be read in three
frames
• AAT TGG CCT: leucine,threonine,glycin
• A ATT GGC CT:stop, proline
• AA TTG GCC T: asparagine,arginine
• Changes in DNA caused by mutation can
cause error in the amino acid
sequence,creating partially or totally non
functional protein (Montague et al,2005)

40. TYPES OF GENE
MUTATION

41. Mutation can occur in two ways.
• Inherited from a parent or germ like
mutation
(they are present in the egg and sperm
cell)
• Acquired mutation
• occurs during a persons lifetime.
Changes can be caused by
environmental factors such as UV
radiation, mistakes made in DNA
copies during cell division,viral
infections

42. Missense mutation
• It is a change in one DNA base pair
result in the substitution for one
amino acid for another in the protein
made by a gene.
• AAT GGC CCT
(leucine,threonine,glycine)
• AAT GCC CCT (incorrect amino acid
which may produce a malfunctioning
protein)

43. Nonsense mutation
• It alters the DNA sequence and
signal the cell to stop building a
protein. It may also result in a
shortened protein that may function
improperly or not at all.
• AAT TGC CCT
(leucine,threonine,glycine)
• AAA TGG CCT (Stop,stop,glycine)

45. Effect of Gene mutation on
health and development
• When a mutation alters a protein
that plays a critical role in the body,
it can disrupt normal development or
cause genetic disorder
• Prevent an embryo from surviving
until birth
• Luckily only a small percentage of
mutation cause genetic disorder and
most have no impact on health.

46. Contd…..
• Recessive gene mutation are not
immediately detected.They are
detected only when they caused a
noticeable change in the phenotype
• Dominant are rare and cause
phenotypic change immediately e.g
aniridia (lack or defect of Iris) in
human

47. BENEFITS OF MUTATION
• DNA can be damaged or mutated in
many ways and DNA repair is an
important process by which the body
protects itself from disease
• Mutation leads to a new version of
protein that helps an organism and its
future generation better adapt to
changes in their environment
• Results in a protein that protects the
organism from a new strain from
bacteria

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