antenatal and postnatal screening

Question 1

what are the types of antenatal screening and what are their benefits

Answer 1

the types are ultrasounds, blood tests, urine tests and diagnostic testing
benefits = risk of disorder can be identified so further tests and a prenatal diagnosis can be offered

Question 2

why are ultrasounds used during pregnancy

Answer 2

8-14 weeks used to determine pregnancy stage and due date

18-20 weeks used to detect serious physical abnormalities

Question 3

why are blood and urine tests carried out during pregnancy

Answer 3

to monitor the concentration of marker chemicals

Question 4

name two types of diagnostic testing

Answer 4

amniocentesis and chorionic villus sampling

Question 5

what are the advantages and disadvantages of amniocentesis

Answer 5

advantages = prenatal diagnosis possible and detects neural tube defects 
disadvantages = small risk of miscarriage and gives results later in pregnancy

Question 6

what are the advantages and disadvantages of chorionic villus testing

Answer 6

advantages = prenatal diagnosis possible and gives results earlier in pregnancy 
disadvantages = does not detect neural tube defects, small chance of miscarriage and may carry risk of defects of fingers and toes if carried out too early

Question 7

what is a karyotype

Answer 7

an image of an individuaks chromosomes, arranged in homologous pairs

Question 8

what types of conditions can a karyotype be used to diagnose

Answer 8

down syndrome, turners syndrome and klinefelters syndrome

Question 9

what is autosomal recessive

Answer 9

allele on chromosome 1-22, expressed in phenotype if the genotype is homozygous for the recessive allele

Question 10

what is autosomal dominant

Answer 10

allele on chromosome 1-22, always expressed in the phenotype

Question 11

what is incomplete dominance

Answer 11

when an allele is not completely masked by a dominant allele, thus affecting an individuals phenotype

Question 12

what is a sex linked recessive single gene disorder

Answer 12

recessive allele carried on the X chromosome

Question 13

what is post natal screening used to detect

Answer 13

certain conditions and abnormalities such as phenylketonuria or deafness

Question 14

how is phenylketonuria (PKU) caused and the effects it can have

Answer 14

caused by a substitution mutation that means an enzyme that is responsible for converting phenylalanine to tyrosine is non functioning
this can effect a babies brain development