Unit 2- Antenatal & Postnatal Screening Flashcards
Describe ultrasound scans.
A dating scan and an anomaly scan are given to run tests.
Describe a dating scan.
Between 8-14 weeks determine the pregnancy stage and due date.
Describe an anomaly scan.
Between 18 and 20 weeks, may detect serious physical abnormalities in the fetus.
Describe a blood urine test.
Carried throughout pregnancy used to determine if a fetus has a medical condition.
What are the 2 types of antenatal diagnostic testing?
Amniocentesis, CVS.
Describe Amniocentesis
It involves taking a sample of amniotic fluid .
Describe CVS
It involves taking a sample of placental cells.
Compare CVS and amniocentesis
CVS can be carried out earlier in pregnancy but has a higher risk of miscarriage.
Describe a karyotype
Cells from samples can be cultured to obtain sufficient cells to produce a karyotype. It shows and individuals chromosomes arranged in homologous pairs.
Describe the use of post-natal screening to diagnose PKU
A baby after birth is given the heel prick test to test for the condition which is a substitution mutation.
What are the 2 types of disorders.
Autosomal, sex linked.
Describe an autosomal disorder.
Mutation is located in autosomes 1- 22, and affect both males and females equally.
Describe a sex linked disorder.
It is located on the X chromosome, affects females more because they have X X chromosomes.
Describe the pattern of autosomal recessive inheritance.
They skip generations, those affected require 2 recessive alleles. Two unaffected carrier (heterozygous) parents can have an affected child.
Describe the pattern in sex linked recessive inheritance
Carried on X chromosome. More males will be affected. Males can only pass the condition onto their daughters. Only affected or carrier females can pas it to their son.
