Chapter 6: Genetics & Genomics in Nursing Insight

Genetics & Genomics in Nursing Insight defines foundational concepts such as deoxyribonucleic acid (DNA), chromosomes, and the distinction between a person's genetic constitution (genotype) and its observable expression (phenotype). The text explores the mechanisms of cell division, differentiating between mitosis and meiosis, and explains how chromosomal alterations like nondisjunction can lead to conditions such as Down syndrome (trisomy 21) or Turner syndrome. A major focus is placed on patterns of inheritance, including Mendelian conditions like autosomal dominant disorders (e.g., Huntington disease, Marfan syndrome) and autosomal recessive disorders (e.g., cystic fibrosis, sickle cell disease), as well as X-linked transmission observed in hemophilia and Duchenne muscular dystrophy. The chapter also examines complex multifactorial inheritance, where genetic and environmental factors combine to cause common health issues like heart disease and diabetes, and mitochondrial inheritance which is passed exclusively from mothers. Significant attention is given to the nature of gene mutations, including germline versus acquired somatic mutations and single nucleotide polymorphisms (SNPs) that contribute to human variation. The description covers the diverse landscape of genetic testing, ranging from carrier and prenatal screening to predictive testing for adult-onset conditions like hereditary breast and ovarian cancer (BRCA mutations) and Lynch syndrome. It delves into pharmacogenetics and pharmacogenomics, explaining how genetic variations in enzymes such as the cytochrome P450 family influence drug metabolism, efficacy, and toxicity, categorizing patients into metabolizer groups ranging from poor to ultrarapid. The nurse's pivotal role is highlighted in conducting genomic-based health assessments, constructing three-generation family pedigrees to identify risk factors, and facilitating referrals to genetic counseling. Finally, the chapter addresses the critical ethical, legal, and social issues (ELSI) surrounding genetics, emphasizing the protections provided by the Genetic Information Nondiscrimination Act (GINA) against insurance and employment discrimination, and the importance of maintaining privacy and confidentiality in the handling of sensitive genetic information.