Top5-Ch6-P146-160End

Question 1

Genetic counselling does what?

Answer 1

Provides information to patients and others who have concerns about human genetic diseases

Question 2

Steps for genetic counselling are

Answer 2

1. Begins with a diagnosis of the condition.
2. Then genetic counsellor meets with patient and members of family and explains diagnosis.
3. Family pedigree may be constructed and probability of passing condition to future generations can be calculated.
4. Ask questions.
5. Explains about genetic testing and then helps to interpret the test results.

Question 3

What is non-directional advise in genetic counselling?

Answer 3

provide information and facilitate discussion but do not bring their own opinions and values into the discussion. this is traditional practise.

Question 4

Because of growing number of genetic tests and the complexity of assessing genetic risk there is now some movement away from completely nondirected counselling. Is this true?

Answer 4

yes.

Question 5

Genetic testing is done to

Answer 5

recognise the potential for a genetic disease to arise at an early stage

Question 6

Name three types of general, overall genetic testing?

Answer 6

1. Prenatal testing
2. Post natal testing
3. Population testing

Question 7

Is genetic testing done for things like sex selection or high IQ or blond hair?

Answer 7

No

Question 8

Name five types of genetic testing and the methods used.

Answer 8

1. Chromosome abnormalities - examination of a karyotype from cells obtained by amniocentesis or chorionic villus sampling
2. Cleft lip and palate - ultrasound
3. Cystic fibrosis - DNA analysis of cells obtained by amniocentesis or chorionic villus sampling
4. Dwarfism - ultrasound or x-ray, some forms can be detected by DNA analysis of cells obtained by amniocentesis or chorionic villus sampling
5. Hemophilia - fetal blood sampling or DNA analysis of cells obtained by amniocentesis or chorionic villus sampling

Question 9

When is ultrasonography used for detecting genetic conditions?

Answer 9

When direct visual can show it, such as with neural tube defects and skeletal abnormalities.

Question 10

Explain amniocentesis

Answer 10

is using needle to pierce abdominal wall to get amniotic fluid so the fetal cells can be used for genetic testing. Performed at about 15-18 weeks of pregnancy.

Question 11

What is chorionic villus sampling?

Answer 11

can be performed earlier than amniocentesis at the 10-12 weeks of pregnancy. Catheter placed into vagina and pushed through cervix into uterus. A small piece of chorion (outer layer of placenta) is taken off for testing.

Question 12

What is a karyotype?

Answer 12

a picture of a complete set of metaphase chromosomes.

wikipedia: A karyotype is the number and appearance of chromosomes in the nucleus of a eukaryotic cell. The term is also used for the complete set of chromosomes in a species, or an individual organism.

Question 13

The amniocentesis and chorionic villus sampling both have ________ risk of spontaneous abortion of the foetus.

Answer 13

increased

Question 14

How thorough are maternal blood screening tests?

Answer 14

They give an indication of increased risk but follow up, more invasive tests need to be done from there.

Question 15

What is fetal cell sorting?

Answer 15

It is a noninvasive fetal diagnosis where it is able to detect and separate fetal blood from maternal blood. this is new and not yet routine.

Question 16

Newborn screening is?

Answer 16

testing for genetic disorders in newborn infants. Many US states have mandatory screening of 29 conditions which is just conducted by placing a drop of the infant’s blood on a card soon after birth.

Question 17

What is presympotmatic testing?

Answer 17

testing healthy adults for genes that might predispose them to a genetic condition in the future. Ie for certain cancers.

Question 18

What is heterozygote screening? And give example of how this has been done.

Answer 18

Population tested to identify heterozygous carriers of recessive disease causing alleles. People tested are healthy but have the potential to produce children with a particular disease.

Example is In USA a group of Ashkenazi Jews has been tested for Tay Sachs. This group has a 100 times higher incidence of Tay Sachs. Heterozygote screening means people at risk of having offspring with Tay Sachs may decide not to have children

Question 19

Name three ways that interpreting genetic tests is complicated

Answer 19

1. presence of multiple causative mutations
2. incomplete penetrance
3. influence of environmental factors.

Question 20

What are direct-to-consumer genetic tests?

Answer 20

Tests where consumer can get the tests done directly with the laboratory for a wide range of tests.

Question 21

Humans and Chimpanzees differ only in ___ of their genomes

Answer 21

1%

Question 22

Name four genes that have been found to relate to humanness?

Answer 22

1. FOXP2 - required for human speech.
2. MCPH1-6 - affects brain size.
3. HAR1 - development of cerebal cortex perhaps which is enlarged in humans.
4. MYH16 - muscle in jaw that affects jaw movement for speech perhaps