Antenatal and Postnatal

Question 1

Antenatal Screening

Answer 1

Antenatal screening identifies the risk of a disorder so that further tests and a prenatal diagnosis can be offered

Question 2

Examples of Antenatal Screening

Answer 2

-Ultrasound imaging
-Blood tests
-Urine tests
-Blood pressure
-Amniocentesis
-Chronic villus sampling
-Karyotyping

Question 3

Ultrasound

Answer 3

When the ultrasound scanner is held against a pregnant women’s abdomen, it picks up high-frequency sounds that have bounced off the fetus. These are converted to an ultrasound image on a computer screen

Question 4

Dating Scan

Answer 4

This is carried out between 8 and 14 weeks to determine the stage of the pregnancy and to calculate due date. Used to test for marker chemicals which vary normally during pregnancy

Question 5

Anomaly Scan

Answer 5

Ultrasound imaging carried out between 18 and 20 which may detect the pressure of any serious physical abnormalities in the fetus

Question 6

Blood/Urine Tests

Answer 6

Moniter the normal physiological changes that occur during pregnancy

Question 7

Routine Tests

Answer 7

Check the health of the pregnant women include - liver, renal and thyroid functions, these tests moniter the concentrations of marker chemicals in the blood

Question 8

False-positive Result

Answer 8

If a chemical is measured at the wrong time during a pregnancy it could lead to a false positive result

Question 9

Diagnostic Test

Answer 9

A definitive test that produces results that can be used to establish without a doubt whether the person is suffering from a specific condition or disorder or not

Question 10

Offer of Diagnostic Test

Answer 10

May be offered if:-
-Screening tests show a potential problem
-A family history of genetic disorder
-Belongs to high risk group (over 35)

Question 11

Karaotype

Answer 11

An individual’s chromosomes arranged as homologous pairs, and it can be used to diagnose a range of conditions

Question 12

Amniocentesis

Answer 12

Carried out between 14 and 16 weeks
Involves withdrawing amniotic fluid containing foetl cells. These are cultured, stained and examined under a microscope to create the karyotype and allows for chromosome abnormalities to be detected

Question 13

Chorionic Villus Sampling (CVS)

Answer 13

Involves taking a tiny sample of placental cells using a fine tube inserted into the mothers reproductive tract. The cells are cultured and used for karyotyping

Question 14

Risk of Tests

Answer 14

CVS can be carried out much earlier in pregnancy than aminocentesis, however, CVS has a higher risk of miscarriage than amniocentesis

Question 15

Pedigree Charts

Answer 15

Can be used to analyse patterns of inheritance in genetic screening and counselling

Question 16

Patterns of Inheritance

Answer 16

Be able to draw, analyse and interpret family histories over three generations to follow patterns of inheritance in the following disorders:- autosomal dominant, incomplete dominance and sex linked recessive single gene disorders

Question 17

Autosomal Recessive Inheritance

Answer 17

-May skip generations
-M/F equal
-Example - Cystic Fibrosis

Question 18

Autosomal Dominant Inheritance

Answer 18

-Trait has to be in all generations
-M/F equal
-Example - Huntington’s disease

Question 19

Autosomal Incomplete Dominance

Answer 19

-Different letters
-Example - Sickle-cell disease

Question 20

Sex-Linked Recessive Traits

Answer 20

-More M than F
-Example - Haemophilia

Question 21

Postnatal Screening

Answer 21

Diagnostic testing for metabolic disorders occurs when the baby is just a few days old

Question 22

PKU Screening

Answer 22

In UK, All new-born babies are screened for PKU by having their blood tested for the presence of excess phenylalanine

Question 23

PKU Causation

Answer 23

In PKU a substitution mutation means that the enzyme which converts phenylalanine into tyrosine is non functional

Question 24

PKU Treatment

Answer 24

Individuals which high levels of phenylalaine are placed on a restricted diet to prevent mental deficiency