Ante And Post Natal Flashcards
What identifies the risk of disorders so that further test and a prenatal diagnosis can be offered ?
Antenatal screening
How many ultrasound scans are given to pregnant woman?
2
When is a dating scan carried out?
Between 8-14 weeks
What do dating scans determine ?
The pregnancy stage and due date
What are dating scans used with ?
With tests for marker chemicals which vary normally during pregnancy
When is an anomaly scan carried out ?
Between 18 and 21 weeks
What may anomaly scans detect?
Serious physical abnormalities in the fetus
Why are routine blood and urine tests carried out throughout pregnancy?
To monitor the concentrations of marker chemicals
What can measuring a chemical at the wrong time during pregnancy lead to?
A false positive
What can an atypical chemical concentration in pregnancy lead to?
Diagnostic testing to determine if the fetus has a medical condition
What 2 techniques are used to diagnose a range of genetic conditions?
Amniocentesis and chorionic villus sampling (CVS)
What is an advantage of CVS over amniocentesis?
CVS can be carried out earlier in pregnancy than amniocentesis
What is a disadvantage of CVS over amniocentesis?
CVS has a higher risk of miscarriage than amniocentesis
Where are sample cells taken from during amniocentesis?
Amniotic flu
Where are sample cells taken from during CVS?
Placenta
The cells from amniocentesis and CVS samples can be cultured to obtain sufficient cells to produce what?
A karyotype to diagnose a range of conditions
What is a karyotype?
It shows an individual’s chromosomes arranged as homologous pairs
In deciding to proceed with these diagnostic tests, what will be assessed?
The element of risk will be assessed, as will the decisions the individuals concerned are likely to make if a test is positive
What condition is caused when the enzyme which converts phenylalanine to tyrosine is non-functional?
Phenylketonuria (PKU)
What type of mutation causes phenylketonuria (PKU)?
Substitiution
How can PKU be treated?
By placing suffers on a restricted diet
Which type of disorders are carried on the autosomes (chromosomes 1-22) and affect males and females equally?
Autosomal
On which chromosome are sex linked disorders carried on?
X
Decide the pattern of inheritance:
Disorder appears in every generation. Each sufferer of the trait has an affected parent
Autosomal dominant
Decide the pattern of inheritance:
More males will be affected than females. Affected males do not pass the condition to their sons, they can only pass the condition to their daughters
Sex linked recessive
Decide the pattern of inheritance:
Disorders skip generations – it does not appear in every generation. Sufferers require two recessive alleles to be affected (homozygous recessive). Two unaffected heterozygous carrier parents can have an affected child.
Autosomal recessive
Decide the pattern of inheritance:
The dominant allele does not fully express itself.. The fully expressed form of the disorder occurs relatively rarely, whereas the partially expressed trait form occurs much more frequently
Incomplete dominance
