1
Q
Human genome project
A
primary goal: to produce a map of every gene that comprises the human genome
- undertaken to lead to interventions that can prevent or treat conditions that have a genetic component
- estimated that 20,500 genes make up the human’s genome
- invaluable in the identification of genes involved in disease
2
Q
Gene therapy
A
- to correct defective genes that are responsible for disease development
- generally involves inserting a healthy copy of the defective gene into the somatic cells (any cell of the body besides sperm or egg)
- has now been moved to preclinical to clinical studies for many diseases (range from hemophilia to cancer)
3
Q
Current prenatal testing options
A
- maternal serum screening
- alpha fetoprotein
- percutaneous umbilical blood sampling
- fetal nuchal translucency (FNT)
- fetal ultrasound level 2
- triple and quad screening tests
- amniocentesis and chorionic villus sampling
4
Q
Fetal ultrasound
A
- fetal heart activity
- gestational age
- fetal growth
- fetal anatomy
- fetal genetic disorders + anomalies
- placental position and function
- fetal well being
5
Q
Amniocentesis
A
- obtains fluid to assess fetal cells
- possible after 14 weeks
- can be used for genetic concerns
- use of ultrasound with amniocentesis
6
Q
Chorionic villus sampling
A
- earlier diagnosis and rapid results
- used in first trimester
- removal of a small tissue specimen from the fetal portion of the placenta
- reflects the genetic makeup of a fetus
- transcervical or transabdominally
7
Q
Predictive testing
A
- used to clarify the genetic status of asymptomatic family member
- mutation analysis for huntington’s disease, a neurodegenerative disorder
- if the gene mutation for HD is present, symptoms of HD are certain to appear
8
Q
Predispositional testing
A
- differs from presymptomatic testing in that a positive result does not indicate a 100% risk for developing this condition
- ex: breast cancer, testing for BRCA 1 gene
9
Q
Risks associated with genetic testing
A
- high false positives
- anxiety
- altered family relationships
- discrimination + stigmatization
- gap between the ability to test for and the ability to treat
- denial of insurance benefits
- ethnic and socioeconomic disparity associated with genetic testing
10
Q
Patterns of genetic transmission
A
- heritable characteristics that can be passed to offspring
- multifactorial inheritance result from two or more genes on different chromosomes acting together
- unifactorial inheritance is controlled by a single gene
11
Q
Multifactorial inheritance
A
- a combination of genetic and environmental factors
- cleft lip
- cleft palate
- congenital heart disease
- neural tube defects
- pyloric stenosis
- can range from mild to severe
12
Q
Patterns of unifactoral inheritance
A
- autosomal dominant
- autosomal recessive
- x linked recessive
- x linked dominant
13
Q
Autosomal dominant inheritance
A
- a single abnormal gene on one of each of the first 22 non sex chromosomes from either parent
- 50% chance of inheriting if one parent has a dominant gene defect
- risk of transmission with each pregnancy is 50% with 1 affected parent
14
Q
Autosomal dominant
A
- neurofibromatosis - progressive disorder of the nervous system that causes tumors to form on nerves anywhere in the body
- huntington’s disease - degeneration of brain cells
- factor V leiden - risk for recurrent venous thromboembolism/pulmonary embolism
- marfan syndrome, dwarfism, mytonic dystrophy
15
Q
Neurofibromatosis (NF)
A
progressive disorder of the nervous system
- causes tumors to form on nerves anywhere in the body
- lesions known as cafe au lait spots
- axillary freckling
- small growths
16
Q
Autosomal recessive
A
- 2 copies of an abnormal gene must be present in order for the disease or trait to develop - both genes in a pair must be defective to cause disease
- people with only one defective gene in the pair are considered carriers, they can pass on the abnormal gene to offspring
- risk of transmission with each pregnancy is 25% with 2 carrier parents
17
Q
Autosomal recessive diseases
A
- sickle cell anemia
- tay sachs disease
- cystic fibrosis
18
Q
Tay sachs disease
A
- fatal genetic lipid storage disease
- common in jews and french canadian
- appear normal at birth but death by 3-4 years of age
- no treatment exists
- nerve cells become distended with fatty material, a relentless deterioration of mental and physical abilities - blind, deaf, unable to swallow
19
Q
X linked dominant
A
- abnormal gene from one parent is capable of causing disease
- location of defective gene —> X chromosome
- risk of transmission at each pregnancy = 50% males and 50% females
- relatively few x linked dominant disorders have been identified, vitamin d resistant ricketts and rett syndrome
20
Q
X linked recessive
A
- location of defective gene: X chromosome
- risk of transmission at each pregnancy: 50% male offspring only, only mother is carrier
- hemophilia & color blindness
21
Q
Down syndrome (trisomy 21)
common genetic disorders
A
- various degrees of mental retardation
- upward slant of eyes
- flat facial profile that includes depressed nasal bridge, small nose, protruding tongue, small, low set ears
- short broad hands with deep creases
- hyperflexibility
- low muscle tone
22
Q
Cancer
common genetic disorders
A
- can be genetic in origin
- breast cancer - most common form of cancer for women - second most common cause of cancer death
- colon cancer - third leading cause of death in women
23
Q
Expanded role of the nurse with genetic expertise
A
- prenatal screening & testing
- neonatal genetic testing & screening
- palliative care for infants with life threatening genetic conditions & their families
- ID & care of individuals with genetic conditions and their families
- care of women during pregnancy with genetic conditions
24
Q
Roles for nurses in genetics
A
- Identification of families in need of genetic counseling
- emotional support
- awareness of responses to testing (denial, anger, hostility, fear, embarassement, grief, guilt, self blame)
- awareness of how families define and manage ethical, legal and social issues
