KA4- Antenatal And Postnatal Screening

Question 1

Antenatal and postnatal screening

Answer 1

A variety of techniques can be used to monitor the health of the mother, developing fetus and baby

Question 2

Antenatal screening

Answer 2

Ultrasound imaging
Blood and urine tests
Diagnostic testing

Question 3

Autosomal

Answer 3

Roughly equal males and females affected
Present on numbers 1-22

Question 4

Autosomal dominant

Answer 4

Affected person in every generation

Unaffected- homozygous recessive
Affected- homozygous dominant or heterozygous

Question 5

Autosomal recessive

Answer 5

Each parent is heterozygous if child is affected

Affected- homozygous recessive
Carriers- heterozygous
Unaffected- homozygous dominant
Can skip a generation

Question 6

Sex linked

Answer 6

More males than females affected

Only present on X chromosome (weird genotype
Affected fathers cannot pass to sons
Can skip a generation
Unaffected males have unaffected/carrier daughters depending on mother
Affected- homozygous recessive
Unaffected- homozygous dominant

Question 7

Autosomal Incomplete dominance

Answer 7

More carriers than sufferers

When some alleles are not fully dominant or recessive so show a mix of both
Genotype: RW
Carriers- heterozygous and partially affected
Affected- homozygous
Unaffected- homozygous

Question 8

Postnatal screening

Answer 8

Diagnostic testing for phenylketonuria
In PKU a substitution mutation means that the enzyme which converts phenylalanine to tyrosine is non-functional.
Individuals with high levels of phenylalanine are placed on a restricted diet