Chapter 5: Genetics and genomics perspectives in nursing

Integrating genetics and genomics perspectives in nursing Genomics: study of human genome, including gene sequencing, mapping, function Nurses must understand new technologies, treatments of genetic-, genomic-based healthcare Nurses must recognise they are vital link between patient, healthcare services May be person patient turns to first for questions, information Nurses must recognise, deal appropriately with ethical issues that may arise related to genetics

Awareness of attitudes, experiences and assumptions Beliefs or values about health Family, religious or cultural beliefs about cause of illness; how one’s values or biases affect understanding of genetic conditions Philosophical, theological, cultural, ethical perspectives related to health How these perspectives influence one’s use of genetics information or services Level of expertise about genetics, genomics

Awareness of attitudes, experiences and assumptions (cont’d) Experiences with birth defects, chronic illnesses, genetic conditions along with one’s view of such conditions as disabling or empowering Attitudes about right to access, other rights of individuals with genetic disorders View, assumptions about DNA, beliefs about value of information about one’s risk for genetic disorders Beliefs about reproductive options View of genetic testing, engineering Approach to patients with disabilities

Five main tasks Help collect, interpret relevant family, medical histories Identify patients, families who need further genetics evaluation and counselling, refer them to appropriate genetics services Offer genetics information, resources to patients, families Collaborate with genetics specialists Participate in management, coordination of care of patients with genetic conditions

Nursing genetics and genomics assessment Family history Physical Ancestry, cultural, social, spiritual Psychosocial

Question Is the following statement true or false? Genomics is the study of the human genome, including gene sequencing, mapping and function

Answer True Rationale: Genomics is the study of the human genome (DNA in the chromosomes and in the mitochondria), including mapping of genes and sequencing of the DNA

Genetics family history Assess risk of certain diseases Decide on testing strategies (what genetic, other diagnostic tests to order) Establish pattern of inheritance Identify other family members at increased risk Identify shared environmental risk factors Calculate risks

Genetics family history (cont.) Assess risk of passing on conditions to children Determine, recommend treatments that modify disease risk Make decisions about management or surveillance Develop patient rapport Educate patients

Genetic counselling: Professional practice Providing pre-counselling information Preparing patients for genetics evaluation Communicating genetic, genomic information to patients Providing support

Genetic concepts Most health conditions now thought to be combination of genetic, environmental influences Human Genome Project: international research effort aimed at identifying, characterising order of every base in human genome Genotype: genes, variations that person inherits from parents Phenotype: person’s entire physical, biochemical, physiologic makeup as determined by person’s genotype, environmental factors

Terms Chromosome: microscopic structures in cell nucleus that contain genetic information, constant in number in a species Cell division: Mitosis Meiosis Gene mutations: heritable alteration in genetic material Genetic variation: variation in degree to which trait is manifested; clinical severity

Question Is the following statement true or false? Meiosis is cell division that occurs in somatic cells that normally result in daughter cells with the same number of chromosomes

Answer False Rationale: Mitosis is cell division that occurs in somatic cells that normally result in daughter cells with the same number of chromosomes. Meiosis is the reduction division of diploid egg or sperm resulting in haploid gametes

Deoxyribonucleic acid (DNA) Primary genetic material in humans consisting of nitrogenous bases, sugar group, phosphate Combined into double helix

Inheritance patterns Autosomal dominant: affects female, male family members equally Follows vertical pattern of inheritance in families Autosomal recessive: pattern is more horizontal than vertical Relatives of single generation tend to have condition X-linked: inherited in recessive or dominant patterns

Autosomal dominant Variable expression Penetrance Examples: BRCA1 breast cancer gene Retinoblastoma Huntington’s disease

Autosomal recessive More frequently seen among particular ethnic groups, more likely in children of parents related by blood ‘Carriers’ Examples: Cystic fibrosis Sickle cell anaemia Tay-Sachs disease

X-linked inheritance May be recessive or dominant Gene located on X chromosome Since males have only one X chromosome, inherited disorder (if recessive) seen in all males who have gene If recessive, females with one affected gene are carriers Have 50/50 chance of passing disorder to son Examples Factor VII, Factor IX haemophilia Duchenne’s muscular dystrophy

Multifactorial inheritance and complex genetic conditions Many common health conditions result from interactions of multiple genes, environment Conditions may cluster in families but do not follow characteristic patterns of inheritance

Chromosomal differences Chromosomal differences: major cause of birth defects, mental retardation, malignancies Extra or missing chromosome or structural rearrangement of chromosome Examples Down syndrome Turner’s syndrome

Genetic testing and screening Genetic testing: primary tool used to identify individuals predisposed to specific genetic diseases Genetic screening: applies to testing of populations or groups independent of positive family history or symptom manifestation

Ethical issues Respect patient’s right to self-determination, autonomy Right to privacy, confidentiality