introduction to genetics in Nursing and its Importance
- 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’ 3/22/2024 2
- 3. Definition • Genetics is the branch of biological sciences which deals with the transmission of characteristics from parents to offspring. 3/22/2024 3
- 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. • 4
- 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. 5
- 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 6
- 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. 8
- 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 9
- 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 10
- 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 12
- 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 17
- 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 18
- 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
- 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)
- 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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