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What does antenatal and postnatal screening involve?

Testing for diseases or conditions in a fetus or embryo before it is born


What does antenatal screening identify?

The risk of a disorder so that further tests and a prenatal diagnosis can be offered


What do common antenatal testing procedures include?

ultrasound scanning, amniocentesis, chorionic villus sampling (CVS) and rhesus antibody testing


What are three uses of an ultrasound used to produce?

An ultrasound image on a computer screen ,gestational dating scan and anomaly scan


What is a gestational dating scan mean?

which is used to determine the stage of pregnancy and date that the baby is due


What is an anomaly scan?

Used to detect the presence of serious physical problems in the fetus


What is an ultrasound?

image on a computer screen


Why are biochemical tests carried out?

To detect marker chemicals that are produced during normal physiological changes that take place during pregnancy


What is a screening procedure?

Tests such as ultrasound imaging that indicates the possible presence of a disorder


What can diagnostic tests like amniocentesis and CVS confirm?

The presence of conditions such as down syndrome


What can cells from amniocentesis and CVS do?

Be cultured to obtain sufficient cells to produce karyotype


What is karyotype?

An image of an individual's chromosomes arranged in homologous pairs


Why is a karyotype used?

To identify anomalies in the number or structure of chromosomes


What are problems with diagnostic test like amniocentesis and CVS?

THey are invasive and carry a small risk of inducing miscarriage


When can CVS be carried out?

Before amniocentesis but has a higher risk of inducing miscarriage


Why is Rhesus antibody carried out earlier in a pregnancy?

To determine the rhesus status of the mother, to ensure that she shows no immune responses to her fetus


what complications can event of a second pregnancy

If a mother is rhesus negative and the fetus is rhesus positive


What is given to negative rhesus mothers after sensitising events such as the birth of a baby?

Anti rhesus antibodies


What does postnatal screening involve?

Health checks that are carried out after the birth of the baby. These are aimed at detecting certain conditions or abnormalities


What is postnatal testing used to detect?

Metabolic disorders such as phenylketonuria (PKU)


What is PKU?

An inborn error of metabolism


How is PKU caused?

By an autosomal recessive genetic disorder


What can individuals with PKU cannot do?

Metabolise excess phenylalanine


What can happen if PKU is not detected soon after birth?

The baby's mental development can be affected


What do people with PKU have to do?

Be placed on a restricted diet that lacks the amino acid phenylalanine


What are pedigree charts compiled and used to analyse?

Patterns of inheritance in genetic screening and counselling


What are pedigree charts constructed to do?

Provide information and advice in situations where there is the possibility of passing on a genetic disorder to potential offspring


What are pedigree charts compiled to do?

To analyse patterns of inheritance in genetic screening and counselling


In what situation are pedigree charts used to provide information and advice?

Where there is a possibility of passing on a genetic disorder to potential offspring


What can pedigree charts be used to analyse?

Patterns of inheritance involving autosomal recessive, autosomal dominant, incomplete dominance and sex linked recessive single gene disorders