genetics

Question 1

genetics

Answer 1

The study of heredity and the focus is on SINGLE genes

Question 2

genomics

Answer 2

study of ALL genes and their inter-relationships and influence on growth and development

Question 3

Who provides genetic services?

Answer 3

Clinical geneticist
Genetic counselor
Nurse practitioner
Other practitioners: including nurses!

Question 4

Why perform genetic testing?

Answer 4

• establish or confirm a diagnosis
• Reproductive decision making, carrier testing, and fetal testing (CF)
• Predict risk for future disease (breast cancer/ huntingtons)
• Aid in management decisions
• Can provide personalized care

cancer genetics can:
Identify who will benefit from high-risk intervention
Individualize screening based on mutation status and family history
Target therapy specifically to the genetic type of cancer
(PARP inhibitors in BRCA carriers, Avoid radiation in TP53 carriers )

Question 5

human genome project

Answer 5

international 13 year effort to produce a comprehensive sequence of the human genome

Goal: Was to map, sequence, and determine the function of all human genes

Question 6

genotype

Answer 6

genes inherited from parents

instructions on how the body is supposed to be built and function

Question 7

phenotype

Answer 7

a person’s entire physical appearance - their outward characteristics

Refers to what you actually see expressed by the genotype. affected by the environment

Question 8

trisomy

Answer 8

three copies of one chromosome
“better to have extra than less”
down syndrome

Question 9

trisomy 21

Answer 9

downs
low nasal bridge, epicanthal folds, protruding tongue, poor muscle tone

Question 10

turner syndrome

Answer 10

Females with only ONE X chromosome (normally have two)

Characteristics:
Absence of ovaries (sterile)
Short stature
Webbing of the neck
Edema
Underdeveloped breasts; wide nipples

Question 11

Klinefelter Syndrome

Answer 11

Individuals with at least TWO X’s and ONE Y chromosome

Characteristics:
Male appearance
Develop female-like breasts
Small testes
Sparse body hair
Long limbs

Question 12

Autosomal Dominant Inheritance

Answer 12

Autosomal dominant inherited conditions affect both female and male family members equally and follow a vertical pattern of inheritance.
Only 1 mutated chromosome = disease
50% chance

ex) hereditary breast/ovarian cancer, familial hypercholesterolemia, Huntington’s disease, marfan syndrome, neurofibromatosis, cowden syndrome

Question 13

aneuploidy

Answer 13

somatic cell that doesnt contain a multiple of 23 chromosomes

Question 14

monosomy

Answer 14

only one copy of any chromosome
often fatal

Question 15

disjunction

Answer 15

normal separation of chromosomes during cell division

Question 16

nondisjunction

Answer 16

usual cause of aneuploidy
failure of homologous chromosomes or sister chromatids to sep normally during meiosis or mitosis

Question 17

cell free DNA (cfDNA)

Answer 17

prenatal; short fragments of DNA
- take blood sample from mom + test

Question 18

autosomal aneuploidy

Answer 18

down syndrome
1 in 800 live births
Mentally challenged, low nasal bridge, epicanthal folds,
protruding tongue, poor muscle tone
* Risk increases with maternal age

Question 19

indications for genetic consult

Answer 19

Developmental Delay
* Intellectual Disability
* Dysmorphic features
* Family History of….
* Failure to Thrive
* Atypical Growth
* Cafe-au-lait macules
* Congenital Defects
* Sensorineural Hearing Loss
* Seizures
* Atypical Sexual Development

Question 20

DNA

Answer 20

genetic info + decoded by translation into protein

DNA chemical bases: A (adenine), G (guanine), T (thymine), C (cystosine)

3 bases – 1 codon = 1 amino acid
* 2 or more amino acids = peptide
* ~50 or more amino acids = protein
A + T, G + C = complimentary base pairs

Question 21

cystic fibrosis

Answer 21

most common, deadly, inherited disorder affecting Caucasians (CFTR gene)

1 in 29 caucasian american have defective gene

autosomal recessive - must inherit both defective CF gene

Question 22

Non-invasive prenatal test (NIPT)

Answer 22

Reports on trisomy 13, 18, and 21
sex chromosome aneuploidies

Question 23

cowden syndrome

Answer 23

PTEN Gene
Mainly hamartomatous polyps throughout GI tract.

colon cancer risk
risk for thyroid, breast, and endometrial cancers

Characteristic skin findings: macrocephaly, lipoma, fibroma

Question 24

autosomal recessive inheritance

Answer 24

when a person has two copies of a mutant autosomal gene of a single copy of a mutant X-linked gene in the absence of another X chromosome.
horizontal pattern; single gen relatives
25% chance

ex. CF, galactosemia, PKU, sickle cell anemia, tay-sach, canavan disease, ataxia telangiectasia

Question 25

genetic testing benefits

Answer 25

Identifies high risk individuals
Identifies non-carriers in families with known mutation
Allows early detection and risk reduction strategies
May relieve anxiety

Question 26

x linked inherited conditions

Answer 26

gene mutation on X chromosome; vertical transmission
ALL MALES
child has 25% chance of dev disease
1in 4 = norm
2 in 4 = carrier

ex) Duchenne Muscular Dystrophy, Hemophilia A, Wiskott-Aldrich Syndrome, Color blindness, fragile X

Question 27

Mitochondrial Inheritance

Answer 27

Only the mother will pass the mitochondrial DNA to offspring and ALL of her children will inherit the disorder

Ex) Leber’s hereditary optic neuropathy, Leigh syndrome, Kearns-sayre syndrome

Question 28

multifactorial inherited

Answer 28

Multiple gene mutations and environmental influences
May cluster in families and not always result in a pattern

ex) congenital heart defects, cleft lip/palate, neural tube defects, diabetes, osteoarthritis, htn, Alzheimer, hypothyroidism

Question 29

PARP inhibitor

Answer 29

women with ovarian cancer who were found to have a BRCA-1 or BRCA -2 mutation

repairing single strand DNA breaks
leads to cell death through a type of directed synthetic lethality, offering a targeted therapy treatment option compared to platinum based chemotherapy

Question 30

nursing role

Answer 30

ensuring informed health choices and consent
Advocating for privacy and confidentiality
Assessing genetic risk
pros/cons of genetic testing
psychosocial needs
Make referrals
explaining risk and genetic predisposition
supporting informed health decisions and opportunities for prevention and early intervention
clarifying legal protections and risks related to genetic testing or health concerns
protect privacy
Assess family history