UNIT2 KA4 antenatal and postnatal screening Flashcards
What does dominant mean
Only 1 is required for a trait to be expressed
What are features of autosomal recessive
Can skip generations
Male and females are equally effected
Individuals can be a carrier without expressing the trait
When can u carry out chrorionic villus sampling
11-14 weeks
What are the two types of ultrasound scans called
Dating scan
Anomaly scan
What is a genome
All of the alleles a individual has
What are the 4 types of disorders
•Autosomal recessive. (cystic fibrosis)
•Autosomal dominant
(Huntington’s disease)
•Autosomal incomplete dominant ( skin cells)
•sex link recessive (haemophilia)
What is a karyotype
The display of homologous chromosomes a individual passes
How long and what is the dating scan
8-14 weeks
Determines the stage of pregnancy and due date
What does heterozygous mean
An individual with 2 different alleles
What is a disadvantage of chorionic villus sampling
Small risk of miscarriage
What does recessive mean
2 are required for a trait to be expressed
What is a disadvantage of amniocentesis
Takes weeks to develope karyotype
What are different types of antenatal tests
- Ultrasound imaging
- Biochemical tests- blood + urine
- Diagnosis tests - amniocentesis + chronic villus sampling
What is a autosomal
Non sex chromosomes
What is postnatal screening
Health checks that are carried out after birth to detect the presence of conditions/abnormalities
What is the sickle cell trait
One abnormal gene but does not display symptoms
What are alleles
The different forms of a gene eg brown, blonde or red hair
What type of mutation is PKU
substitution
When can u carry out amniocentesis
15-18 weeks
What is a carrier
An individual who carries a recessive trait without expressing it
What type of disorder is PKU and what system does it effect
Recessive
Inborn error of metabolism
What are features of sex linked recessive
More common in males
Carried on X chromosomes
What is a gene
1 type of characteristic eg hair colour
What can antenatal screening help identify
Down syndrome
Spina bifida
Cystic fibrosis
Muscular dystrophy
What are features of incomplete dominant
Male and females are equally effected
Heterozygous traits are more common
How long and what is the anomaly scan
18-20 weeks
Used to detect only physically abnormalities in the developing fetus
What does homozygous mean
An individual with 2 identical alleles
What are features of autosomal dominant
Males and females equally effected
No carriers- heterozygous would express the trait
What are phenotypes
Physical characteristics
What are advantages of chronic villus sampling
Given karyotype immediately
How many alleles are required to express PKU
2
What is the treatment for PKU
Placed on restricted diets that lacks phenylalanine
What are the 2 types of diagnosis tests
Amniocentesis
Chronic villus sampling
