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What is genetics?

Study of individual genes and their effects on relatively rare, single-gene disorders


What is genomics?

Study of all the genes in the human genome together, including their interactions with each other, the environment, and the influence of other psychosocial factors and cultural factors


What do these studies [genetics and genomics] allow us to do?

Allows us to predict susceptibility, onset, progression, and response to treatment for many hereditary diseases


How many genes are in the human genome?



What does gene therapy do?

-corrects defective genes that are responsible for disease development.
-Involves inserting a healthy copy of the defective gene into the somatic cells of the affected individual.
-Diseases that could be treated with this range from hemophilia and other single-gene disorders to complex disorders such as cancer


What are the reasons patients decide either to be tested or not tested?

-Seldom autonomous
-Based on feelings of and commitment to others
-Socioeconomic factors
-Cultural and ethnic differences
-Gap in ability to diagnose and ability to


How should genetic history be obtained for genetic counseling in pregnancy?

Questionare or checklist


What is the goal of genetic counseling?

The goal is to identify a risk.


What is an occurrence risk?

Parents are known to be at risk for producing a child with disease; what’s the risk of their child having the disease?


What is a recurrence risk?

Once they have produced a child with disease, what’s the chance their next child will also have the disease?


Interpretation of risks?

very personal decision-making process for parents


What kind of screenings fall under population based screening?

Newborn screening for phenylketonuria [PKU]


What is predictive testing/screening?

it is used to clarify the genetic status of asymptomatic family members


What are the two types of predictive testing?

Presymptomatic testing

Predispositional testing


What is presymptomatic testing?

if the gene mutation is present, symptoms of the disease are certain to appear if the individual lives long enough. (i.e Huntington's Disease)


What is predispositional testing?

BRCA 1 gene, a positive does not indicate a 100% risk for developing the condition (breast cancer)


What are prenatal tests used for?

used to identify the genetic status of a fetus at risk for a genetic condition (done in 1st trimester)


What is maternal serum screening?

Maternal serum screening: a blood test used to see if a pregnant woman is at increased risk for carrying a fetus with a neural tube defect (NTD) or chromosomal abnormalities (Down syndrome, Trisomy 18 or Trisomy


What is a fetal ultrasound?

Imaging of the fetus inside the uterus obtained by using high-frequency sound waves. Can screen for physical features associated with genetic abnormalities


What is amniocentesis and when is it done?

Invasive procedure that obtains fetal DNA from amniotic fluid; after 15 weeks gestation


What is chorionic villus sampling and when is it done?

invasive procedure obtaining fetal DNA from chorionic villi; before 15 weeks gestation


What are alleles?

genes that code for variations of the same trait…hair color, eye color, etc


What is a karyotype?

A pictorial analysis of the number and size of an individual's chromosomes


What is a pedigree chart?

Way to show the inheritance pattern of a trait or illness


What are chromosomal abnormalities?

A major cause of reproductive loss, congenital problems, and gynecologic disorders

Can occur during mitosis (somatic cell-autosomal disorders) or meiosis (sex cells-sex-linked disorders)


Type of autosomal chromosomal abnormality

Downs syndrome (trisomy 21)


What is trisomy 18?

Edwards’ Syndrome

Severe to profound intellectual disability

Most don’t survive to their 1st birthday


What are the types of chromosomal abnormalities in regards to sex chromosomes?

Turner syndrome

Klinefelter syndrome


What is Turner syndrome?

Monosomy x

Most common deviation in females

Short in stature and webbing of neck,

low hairline; intelligence may be impaired


What Klinefelter syndrome?

Trisomy xxy
Most common deviation in males
Affected males have poorly developed secondary sexual characteristics and small testes. Usually infertile, usually tall and may be slow to learn