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Flashcards in Genetics Deck (34)
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1
Q

an anatomic or structual abnormality which is present at birth

A

Congenital malformation

2
Q

Percentage of perinatal deaths that are due to the presence of congenital malformations

A

20%

3
Q

Any substance capable of causing abnormal structure in an embryo

A

Teratogen

4
Q

Causes of congenital malformations

A

Genetic factors
Environmental factors
Multifactorial inheritance
Sensitive concept

5
Q

Certain structures are _________ to certain teratogenic agents at given times and only at given times. _______ event cannot influence the development of a structure if it occurs before or after that structure differentiates or develops

A

Sensitive,

Noxious

6
Q

The three catagories that teratogens are devided into are

A
  1. Physical agents
  2. Drugs and chemical agents
  3. Maternal factors
7
Q

Radiation,
heat,
mechanical factors like uterine anomalies and fibroids

A

Physical agents (Teratogen)

8
Q

DES, Coumadin, alcohol, anti-thyroid drugs, methotrexate, retinoic acid/ vitamin A, valproic acid for seizures, trimethadione, thalidomide, methylmercury, and many others

A

Drugs and chemical agents (Teratogen)

9
Q

Include diseases such as diabetes and sickle cell anemia and maternal infections. There are many others

A

Maternal factors (Teratogen)

10
Q

Genetic defects that can be identified and diagnosed microscopically

A

Chromosomal abnormalities

11
Q

__________________ usually affect a large part of the fetus and Genome are associated with multiple anatomic abnormalities, mental retardation and high mortality rate

A

Major chromosome abnormalities

12
Q

Genetic diseases can be the result of:

A
  • An abnormal number of chromosomes such as 13, 18, 21
  • Abnormal structure of one or more chromosomes
  • Single gene defects which are inherited as autosomal dominant or autosomal recessive
13
Q

First trimester testing is performed between ______ and _________weeks and involves two parts

A

11.5 and 13.5

14
Q

Types of genetic testing done during the firs trimester

A
  • Nuchal translucency

* Maternal blood test of free or total beta hCG and PA PP- A (pregnancy associated plasma protein A)

15
Q

The combination of the two test done in the first trimester are done to test for

A

85% of Down syndrome (trisomy 21), & trisomy 18 (Edward’s syndrome)

16
Q

Measures the fluid filled area at the back of the neck between 11.5 and 13.5 weeks

A

Nuchal translucency screening

17
Q

In what plane is the Nuchal translucency screening done?

A

Sagittal

18
Q

How is the Nuchal translucency measured?

A

The measurement is taken inner to inner

19
Q

Nuchal translucency is normal if it is

A

less than 3mm

20
Q

The __________ which is ____________ to the fetus should not be mistaken for increased nuchal translucency

A

Amnion, adjacent

21
Q

If the Nuchal translucency is increased,

A

genetic testing of the fetus is performed

22
Q

If the fetus has a normal Karyotype

A

the fetus should be screened for cardiac abnormality in the mid-to-late trimester

23
Q

PA PP-A and beta hCG are produced by

A

trophoblastic tissue

24
Q

Low levels of PA PP-A and beta hCG may indicate

A

abnormal implantation
poor placentation
risk of trisomy 21

25
Q

An invasive test where a needle is placed within the uterine cavity via the cervix, and samples of the chorion or trophoblastic tissue, cells are obtained to evaluate for chromosomal abnormality

A

Chorionic villus sampling or CVS

26
Q

Testing done in the second trimester known as the quadruple is made up of what tests?

A
  1. Maternal serum alpha-fetoprotein, MS AFP
  2. Human chorionic godadotropin, hCG
  3. Unconjugated estriol or E3
  4. Inhibin A
27
Q

a glycoprotein which is produced primarily in the fetal liver. It crosses the placenta into the maternal serum and can easily be detected with a blood test called the maternal serum alpha-fetoprotein

A

Alphafetoprotein or AFP

28
Q

When can AFP be evaluated

A
  • Incorrect dates (patient is further along in the pregnancy than she thought) *especially if AFP is decreased
  • Multiple gestations
  • Open neural tube defects
  • Abdominal wall defects
  • Sacrococcygeal teratoma in the fetus
  • Maternal fetal hemorrhage
  • Placental Chorioangioma
29
Q

Chromosome abnormalities

A
  1. Fetal demise
  2. Trisomy 21/ Down syndrome
  3. Trisomy 18/ Edwards syndrome
30
Q

Increased MS AFP
Increased beta hCG
Decrease in E3
Increase in Inhibin A

A

Trisomy 21/ Down syndrome

31
Q

Decreased MS AFP
Decreased hCG
Decreased E3

A

Trisomy 18/ Edwards syndrome

32
Q

If the ultrasound evaluation fails to establish a cause for abnormal quadruple screen test, then __________ is offered to the patient to evaluate amniotic fluid levels of AFP and for fetal chromosome Karyotyping

A

Amniocentesis

33
Q

An invasive procedure whereby ultrasound is used to guide needle placement into the amniotic cavity

A

Amniocentesis

34
Q

When is an Amniocentesis performed?

A

at around 16 weeks