introduction to genetics in Nursing and its Importance

Nursing

1. Introduction to Genetics
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2. Concept of genetics
•ThetermGeneticswasintroducedby
Batesonin1996.
•DerivedfromGreekword‘gene‘which
means‘tobecome’or‘togrowinto’
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3. Definition
•Geneticsisthebranchofbiological
scienceswhichdealswiththe
transmissionofcharacteristicsfrom
parentstooffspring.
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4. Practical application of genetics in
nursing
Application of genetics in nursing is very wide
since:
•Allnurseshavearoleindeliveryofgenetics
services
•Nursesrequiredgeneticknowledgeto
identify,support,referandcarefor
personsaffectedwithgeneticsdisorder.
•Nursescanoffercarethatprotects
patients&familiesfromtheriskassociated
withgeneticinformation.
•
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5. •Nursesarealsoneededtoreferpatientsto
geneticspecialistandassistinmakingchoiceof
genetichealthcare.
•Geneticsnursingispracticedindifferent
environmentsuchasmaternity,paediatrics,
medicalsurgicalnursing.
•Geneticsnursingisholisticpracticethat
assessing,planning,implementing&evaluatingthe
physicalaspectsofpatients&families.
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6. Major practical application of genetics in
nursing
1.Understandthegeneticsbasisofdiseases.
2.Early&effectivediagnosisofgenetics
disorders.
3.Contributestowardshealthpromotionwith
geneticsaspects.
4.Preventionofgeneticsconditions
5.Managementingeneticsdisorders
6.Geneticsinformation&counselling
7.Referralservices
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7. 7
Impact
of
genetics
condition
on
families
Social
impact
Psychological
impact
Economic
impact
Physical
cognitive
impact

8. Factorsinfluencingtheimpactofgeneticsconditions
onfamilies
1.Thesize,structure&stageofthefamily
2.Religions,ethnic&culturebeliefs
3.Availabilityofrelationshipswithextendedfamily
membersorclosefriends
4.Thepriorstatusoftherelationshipbetween
parents
5.Severityofthedisorders
6. Variablerelatingtoindividualfamily
members.
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9. Role of nurse in managing the impact
Recognizethatdifferentpeoplecopewithshockin
differentways.
Buildatrustingenvironment
respecttheparentsfeeling
Buildfamilystrength
Taughtthespecialcareprocedure,suchasmovingthe
childwithosteogenesisimperfectaorfeedingthecleft
palatechild.
Helpsindecisionmaking
Observetheinteractionofparentswithchild,family
Helptheparentstomaintaincommunication
Ascertainthesupportsystem
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10. Contactpatientsgroupsofpersonswith
similaraffectedchildren
Workwithpatientstoplanatimetable
Giveopportunitiestoaskquestions.
Refertotheadvancedcarefacilities
Helpsthefamilytorebuildselfesteem
Followupcare
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11. Characteristics
& structure
of genes
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12. •Thetermgeneswasintroducedby
Johanssenin1990.
•Geneisdefinedasaunitofinheritance
composedofsegmentofDNA or
chromosomessituatedatspecificlocus
whichcarriescodedinformationassociated
withspecificfunction&undergocrossing
overaswellasmutation
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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
•Itisabasicphysicalandfunctionalunit
ofheredity
•Itiscarriedfromparentsbyagametein
achromosome andcontrolsthe
expressionofacharacterintheyoung
onesinco-operationwithitsallelegene
andenvironment
•PurposeforGenesistocodeformakinga
specificproteinusedbyacell,tissuesor
organwithinaperson.

15. •Humanbeinghavebetween20,000and
25,000genes(HumanGenomeProject)
•Everypersonhas2copiesofeachgene,one
inheritedfromeachparents
•Mostgenesaresameinallpeopleexceptsmall
numberofgene(lessthan1%)andthese
smalldifferencescontributetoeachpersons
uniquephysicalfeature.

17. Types of genes
•Constitutivegene:thosegenewhichareconstantly
expressingthemselvesinacell.
•Nonconstitutive(luxury)gene:notalwaysexpressing
•Induciblegene:thegeneareswitchedoninresponse
tothepresenceofchemicalsubstance(inducer)
•Repressivegene:continuetoexpressthemselvestill
achemicalinhibitstheiractivity
•Repeatedgenes:thegenepresentinmultiplecopies,
e.gtRNAgenes,rRNAgenes
•Singlecopygene:presentinsinglecopy
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18. •Pseudogenes:unabletoproducefunctional
products.
•Splitgenes:whichpossessextraornon
essentialregion
•Jumpinggenes:thatcanjumpormovefromone
placetoanother
•Overlappinggenes:genethatoverlap
•Structuralgenes:whichhaveencoded
informationforthesynthesisofchemical
substancesforcellularactivity
•Regulatorygenes:thatcontrolthefunctionof
structuralgene
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19. DNA: Deoxyribonucleic
Acid
•Quantity:TheDNAcontentisfairly
constantinallthecellsofagiven
species.Justbeforecelldivision,
theamountofDNAisdoubled.The
gameteshavehalftheamountof
DNAastheycontainhalfthe
numberofchromosomes.

20. Chemical Structure
•largestmacromolecule
•longdoublechainofdeoxyribonucleotideunits
•right-handeddoublehelix(spiral)
•Phosphate,a5-Carbondeoxyribosesugaranda
Nitrogenousbase
•Adenine(A)orGuanine(G)
•Thymine(T)orCytosine(C)
•nitrogenousbasemoleculesarejoinedtosugar
moleculeat1-Carbonpositionbyglycoside
bonds
•twodeoxyribonucleotidechainsareheld
togetherbyhydrogenbonds.

23. Some Important Points Regarding DNA
•HumanDNAisdoublestrandedhelicalstructure
comprisedoffourdifferentbases,thesequenceof
whichcodesfortheassemblyofaminoacidstomake
aproteine.g.anenzyme.Theseproteinsare
importantforfollowingreasons:
–Forbodycharacteristicssuchaseyecolor.
–Forbiochemicalprocessessuchasthegenefor
theenzymethatdigestsphenylalanine.
–Forbodystructuresuchaschromosomecollagen
geneimportantforboneformation.
–Forcellularfunctioningsuchasgenesassociated
withcellcycle.

24. ThefourDNAbasesareAdenine,Guanine,
Cytosine,ThymineorAGTC.
•Achange,ormutation,inthecodingsequence,
suchasduplicatedordeletedregionorevena
changeinonlyonebase,canaltertheproduction
orfunctioningofthegeneorgeneproduct,thus
affectingcellularprocesses,growth &
development.
•DNAanalysiscanbedoneonalmostanybody
tissue(blood,muscle,skin)usingmolecular
techniques(notvisibleundermicroscope)for
mutationanalysisofaspecificgenewithaknown
sequenceforDNAlinkageofgeneticmarkers
associatedwithaparticulargene.

26. CHROMOSOME
•Chrome=colour,Soma=body(Weldeyerin
1888)
•Itpointstothefactthatchromosome
easilytakesupbiologicalstains
•Capableofreplication(productionof
exactcopiesofchromosome)
•Theystoreandtransmitcoded
informationaboutbiologicalactivities

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 23
rd
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
Downsyndrome(trisomy21)
•Itiscausedbyhaving3copiesorextra
partofchromosome21.
•Characteristicsaremildtomoderate
learningdisabilities
•Mentalretardation(50-60%)
•G.Iobstruction,ASD,VSD,Leukemia
•Severehypotonia,brachycephaly
•Singlepalmercreases(50%)

33. Klinefelter syndrome
•ItresultsfromextraXinmale.
•Theyhaveagenotypeof47(XXY)
insteadofXYgenotype.
Characteristics
•Shy,sterile,
•Higherincidenceofdyslexiaand
speechproblem
•Enlargedbreast,smalltestes

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
•Disorderofmutationinchromosome
4whichcodesforaproteincalled
Huntinton
•Autosomaldominanttraittherefore
anaffectedparentshave50%
chanceofhavinganaffectedchild.
•Characteristics
-Earlysignsincludeclumsiness,lackof
concentration,memorylapses
-Huntinton,schorea(jerkyand
uncontrolledmovement)

38. MUTATION
•ItisapermanentchangeintheDNA
basesequencethatmakesupagene
•Theyarecapableofchangingthe
phenotypeofanindividual.
•Cellsdependsonthousandofproteinto
functionscorrectly.Amutationthat
altersaproteinwhichplaysavery
importantroleinthebodycanresultina
medicalconditionssuchas
• cancer,leukemiaetc

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. Mutationcanoccurintwoways.
•Inheritedfromaparentorgermlike
mutation
(theyarepresentintheeggandsperm
cell)
•Acquiredmutation
•occursduringapersonslifetime.
Changescanbecausedby
environmentalfactorssuchasUV
radiation,mistakesmadeinDNA
copiesduringcelldivision,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
•ItalterstheDNAsequenceand
signalthecelltostopbuildinga
protein.Itmayalsoresultina
shortenedproteinthatmayfunction
improperlyornotatall.
•AAT TGC CCT
(leucine,threonine,glycine)
•AAATGGCCT(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
•DNAcanbedamagedormutatedin
manywaysandDNArepairisan
importantprocessbywhichthebody
protectsitselffromdisease
•Mutationleadstoanewversionof
proteinthathelpsanorganismandits
futuregenerationbetteradaptto
changesintheirenvironment
•Resultsinaproteinthatprotectsthe
organismfromanewstrainfrom
bacteria

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