ch. 3 genetics Flashcards
genetics
study of a particular gene
genomics
study of all genes in the entire genome
genes
physical units of heritance
genome
entire set of genetic instructions found in a cell
epigenetics
focuses on genetic changes not due to any underlying change in DNA sequence
- covid vaccine: sends message to mRNA to fight virus
precision medicine (or health)
disease prevention/health promotion
- helps HCP discover individual client’s disease risks & treatments best for them
- cancer treatment
nursing expertise in genetics and genomics
1) essential competencies for all nurses
- all nurses need to have minimal competencies to genetics and genomics regardless of their academic preparation, practice setting, and specialty
2) expanded roles for nurses with expertise in genetics and genomics are developing in many areas of maternity and women’s health nursing
examples of current perinatal testing options
1) preimplantation testing: involves couples seeking care for infertility
2) cell free fetal DNA screening: blood test performed at 8-9 weeks
- more available to all pregnant women
3) prenatal microarray testing: performed on cells from CVS or amniocentesis. detects extra or missing genetic information (copy variants) (looking at direct fetal cells for both sources)
4) whole exome sequencing: looks at all protein coding genes
5) whole genome sequencing: sequences an organism’s entire genome at one time
human genome project: implications for clinical practice
1) key findings: all human being are 99.9% identical at the DNA level
2) ENCODE project: organized to identify the genome’s functional elements
human genome project: implications for clinical practice (importance of family history)
1) completion of the human genome project has resulted in renewed interest in family history
2) single most cost effective piece of genetic information
3) US department of health and human services has designated Thanksgiving as “national family history day”
4) many family history tools are available online
human genome project: implications for clinical practice (gene identification)
1) gene identification and testing:
- valuable resource: genetic testing registry
- many kinds of genetic testing
- rapid development of prenatal testing options
2) gene identification and testing:
- predictive testing: presymptomatic testing, predispositional testing
human genome project: implications for clinical practice (population based screening)
1) newborn screening
2) carrier screening for single-gene disorders:
- cystic fibrosis
- sickle cell disease
- tay sach’s disease
3) expanded carrier screening now encourages
human genome project: implications for clinical practice (pharm)
1) pharmocogenomic (PGx) testing:
- performed to examine an individual’s genes to determine how medications are absorbed, move through the body, and are metabolized by the body
2) gene therapy:
- aim is to correct defective genes that are responsible for disease development
- inserting a healthy copy of the defective gene into somatic cells of the affected individuals
human genome project: implications for clinical practice (ethical, legal, and social implications (ELSIs)
1) privacy and fairness in use and interpretation of genetic information
2) clinical integration of new genetics technologies
3) ethical issues including the process of informed consent
4) education for professionals and general public about genetics and the complex issue that result from genomic research
human genome project: implications for clinical practice (factors influencing the decision to undergo genetic testing)
1) decision often based on feelings of responsibility and commitment to others
2) cultural and ethnic differences
3) raises fundamental questions about the mutual obligations of kin
clinical genetics: genetic transmission
1) human development is a complicated process; it depends on systematically unraveling genetic material
2) development from conception to birth usually occurs without incident
3) birth defects occur in 1 of every 33 babies born in the US
clinical genetics: genes and chromosomes
1) DNA -> chromosomes -> genes
2) homologous: 23 matched chromosomes
3) autosomes: 22 pairs
4) sex chromosomes: 1 pair, XX or XY
- loci
- alleles: homozygous, heterozygous
clinical genetics: genes and chromosomes
1) genotype:
- the genetic makeup of a specific gene pair, or sometimes used to refer to an individual’s entire genetic makeup
2) phenotype:
- the observable expression of an individual’s genotype
- ex: brown hair, olive skin
3) dominant
4) recessive
5) karyotype:
- pictorial analysis of nucleic form and size of an individual’s chromosomes
- ex: missing genes, size of individual chromosomes
clinical genetics: abnormalities
1) chromosomal abnormalities:
2) autosomal abnormalities
3) abnormalities of chromosome number:
- euploid cell: correct number of chromosomes
- poluploidy (extra)
- aneuploidy (absent)
- monosomy (one): union between a normal gamete and one that is missing a chromosome
- trisomy: (21 - down’s, 18 - edward syndrome, 13 - patau syndrome)
- nondisjunction: failure of chromosomes to separate normally
clinical genetics: chromosomal abnormalities
autosomal abnormalities
1) abnormalities of chromosome structure
2) translocation: robertsonian
3) reciprocal: balanced, unbalanced
4) deletion: terminal deletion, interstitial deletion, microdeletion
5) inversion
6) sex chromosome abnormalities
7) turner syndrome: monosomy X female
8) klinefelter syndrome: trisomy XXY male
clinical genetics: patterns of genetic transmission
1) multifactorial inheritance
2) unifactorial inheritance
(a) autosomal dominant inheritance
- ex: neurofibromatosis (NF), factor V leiden (FVL), mardan syndrome, myotonic dystrophy
(b) autosomal recessive inheritance (sickle cell)
(c) inborn errors of metabolism
(d) X linked dominant inheritance
(e) X linked recessive inheritance
- fragile X
cancer genomics
1) gene mutations that can lead to cancer
2) three main ways that people acquire gene mutations that can lead to cancer:
- environmental factors (pesticides)
- acquire by chance
- inherited (breast cancer)
3) two main types of genes that play a critical role in the development of cancer:
- oncogenes
- tumor suppressor genes
4) hereditary breast and ovarian cancer
- BRCA 1/ BRCA 2
5) colorectal cancer: two examples of predisposing genes
- APC tumor suppressor gene
- mutations in two MMR genes (i.e. MLH1 or MLH2) result in hereditary nonpolyposis colon cancer (HNPCC) (Lynch syndrome)
genetic counseling
1) definition of genetic counseling
2) access and referral to genetic counseling
3) estimation of risk
4) interpretation of risk
5) multiple roles for nurses in genetic counseling
- identify families in need of genetic counseling
- make referrals to specialists
- provide information about genetics
- provide emotional support
future promise of genetics
- remarkable advances made through the human genome project
- increased availability of genetic testing and other genetic services
- awareness of genetic risk can facilitate informed health care
- advances in molecular biology
- ability to offer diagnostic, preventative, and treatment options not only for genetic diseases, but also for common diseases (eg. cancer, atheroscleorosis, diabetes, alzheimer disease)
what best describes the pattern of genetic transmission known as autosomal recessive inheritance?
disorders in which both genes of a pair must be abnormal for the disorder to be expressed
