NURS 6501 Advanced Pathophysiology Week 2 Study Notes
Topic: Genetics and the Genetic Environment in Disease Module: Module 1 (Foundational Concepts of Cellular Pathophysiology) – Week 2
Primary Textbook Reference: McCance, K. L., & Huether, S. E. (Latest edition, e.g., 8th or 9th). Pathophysiology: The Biologic Basis for Disease in Adults and Children. Elsevier. Key Chapters: Chapter 4: Genes and Genetic Diseases (focus up to “Elements of formal genetics”; include summary review).
Chapter 5: Genes, Environment-Lifestyle, and Common Diseases (focus up to “Genetics of common diseases”; include summary review).
These chapters build on Week 1’s cellular processes by explaining how genetic factors interact with environmental influences to cause or modify disease.1. Basics of Genetics and Molecular FoundationsDNA Structure and Function: Double helix; genes as functional units encoding proteins. DNA replication, transcription (to mRNA), translation (to proteins via ribosomes).
Gene Expression: Regulated by promoters, enhancers, transcription factors. Epigenetics: Modifications (e.g., methylation, histone acetylation) alter expression without changing DNA sequence; influenced by environment (diet, stress, toxins).
Mutations: Changes in DNA sequence.Point mutations (substitution, e.g., sickle cell: GAG → GTG in beta-globin gene).
Insertions/deletions (frameshift), chromosomal abnormalities.
Types of Genetic Alterations:Germline (inherited, present in all cells).
Somatic (acquired, e.g., in cancer).
2. Patterns of Inheritance (Mendelian Genetics)Autosomal Dominant: One mutated allele sufficient (e.g., Huntington’s disease, Marfan syndrome). 50% transmission risk.
Autosomal Recessive: Two mutated alleles required (e.g., cystic fibrosis, sickle cell anemia, Tay-Sachs). Carriers asymptomatic; 25% affected offspring if both parents carriers.
X-Linked Recessive: Males more affected (e.g., hemophilia, Duchenne muscular dystrophy). Females carriers.
X-Linked Dominant: Rare (e.g., fragile X syndrome in some presentations).
Mitochondrial Inheritance: Maternal only (e.g., some myopathies).
Penetrance and Expressivity: Not all with genotype show phenotype (incomplete penetrance); variable severity (expressivity).
3. Chromosomal DisordersNumerical Abnormalities:Aneuploidy: Trisomy 21 (Down syndrome – maternal nondisjunction common), Klinefelter (XXY), Turner (XO).
Structural Abnormalities: Deletions, duplications, translocations (e.g., Philadelphia chromosome in CML).
Genomic Imprinting: Gene expression depends on parent of origin (e.g., Prader-Willi vs. Angelman syndrome – deletion on chromosome 15).
4. Multifactorial/Polygenic Diseases (Genes + Environment)Most common diseases: Interaction of multiple genes (polygenic) + environmental/lifestyle factors (e.g., type 2 diabetes, hypertension, coronary artery disease, some cancers).
Threshold Model: Liability exceeds threshold → disease manifests.
Genetic Risk Factors: SNPs (single nucleotide polymorphisms) increase susceptibility (e.g., BRCA1/2 mutations in breast/ovarian cancer – high penetrance but not 100%).
Environment-Lifestyle Influence: Diet, smoking, exercise, toxins modify gene expression (epigenetics) and interact with genetic predisposition.
5. Key Genetic Concepts in DiseaseSingle-Gene Disorders vs. Complex Diseases.
Proband: First diagnosed individual in family pedigree.
Pedigree Analysis: Autosomal dominant (vertical transmission), recessive (horizontal, skips generations).
Genetic Testing and Counseling: Indications, limitations (e.g., variants of unknown significance).
Cancer Genetics (Intro): Oncogenes (gain-of-function), tumor suppressors (loss-of-function), e.g., TP53 in Li-Fraumeni syndrome.
6. Nursing Implications for Advanced PracticeRecognize genetic red flags: Family history of early-onset disease, multiple affected relatives, ethnic predispositions (e.g., Ashkenazi Jewish – BRCA, Tay-Sachs).
Patient education: Risk assessment, screening (e.g., genetic counseling referral), lifestyle modification to mitigate environmental risks.
Pharmacogenetics: Drug response varies by genotype (e.g., warfarin dosing influenced by CYP2C9/VKORC1).
Ethical considerations: Privacy, discrimination (GINA in US), informed consent for testing.
Week 2 Assignment Focus (Module 1 Case Study Analysis – Due Day 7 of Week 2):
Typically a 1–2 page analysis of an assigned case study scenario (e.g., patient with immunosuppression symptoms like cellulitis, fever, or infection; or genetic-linked condition). Requirements include: Identify genes/processes associated with the disease.
Explain immunosuppression effects on body systems.
Link symptoms to pathophysiology, including genetic/environmental factors.
Use APA, cite McCance & Huether heavily.
Knowledge Check/Quiz Tips (if applicable in Week 2): Questions often cover inheritance patterns, mutation types, chromosomal disorders (e.g., “Klinefelter karyotype? XXY”), imprinting (Prader-Willi), common causes (Down syndrome – nondisjunction).
Study Strategies: Create tables: Compare inheritance patterns (transmission, examples, risks).
Draw pedigrees for practice.
Focus on gene-environment interaction examples.
Review summary reviews at chapter ends.
Collepals.com Plagiarism Free Papers
Are you looking for custom essay writing service or even dissertation writing services? Just request for our write my paper service, and we'll match you with the best essay writer in your subject! With an exceptional team of professional academic experts in a wide range of subjects, we can guarantee you an unrivaled quality of custom-written papers.
Get ZERO PLAGIARISM, HUMAN WRITTEN ESSAYS
Why Hire Collepals.com writers to do your paper?
Quality- We are experienced and have access to ample research materials.
We write plagiarism Free Content
Confidential- We never share or sell your personal information to third parties.
Support-Chat with us today! We are always waiting to answer all your questions.
