Genetics Flashcards
How can placental tissue be obtained for genetic testing?
Chorionic villus biopsy from 11.5 weeks gestation
How can skin/urine cells of a foetus be obtained for genetic testing?
Amniocentesis from 16 weeks gestation
How can blood of a foetus be obtained for genetic testing?
Foetal blood sampling from 18 weeks gestation
How can foetal DNA be obtained for genetic testing?
Maternal serum from 8 weeks gestation
Rank chorionic villus biopsy, amniocentesis, foetal blood sampling and maternal serum in order of greatest to smallest risk of miscarriage
Chorionic villus biopsy
Foetal blood sampling
Amniocentesis
Maternal serum (no risk)
Rank chorionic villus biopsy, amniocentesis, foetal blood sampling and maternal serum in order of most viable to least viable tissue
Chorionic villus biopsy
Foetal blood sampling
Maternal serum
Amniocentesis
What is confined placental mosaicism?
Discrepancy between chromosomal makeup of placental cells and cells in the baby
List the indications for chromosomal analysis in pregnancy
Raised maternal age
Increased risk on screening: nuchal thickness, serum, DNA
Abnormality on ultrasound
Known parental abnormality
What does array CGH analyse?
Changes in the number of copies of a particular gene in a diseased state
Basically looks at chromosome makeup
List the 4 main genetic tests used for chromosome analysis
Array CGH
Standard karyotype
FISH
QF-PCR
What does pre-implantation genetic diagnosis (PGD) involve?
Perform a genetic test on an embryo before re-implanting it with “correct” genetic info
What method is used to implant genetic info in PGD?
Intra-cytoplasmic sperm injection (ICSI)
How old is the embryo when it is biopsied in PGD?
3 days
