Antenatal Genetics and Pregnancy Flashcards
How do you genetically test the Placenta?
Chorionic villus biopsy at 11.5 weeks
How do you genetically test the skin/urine cells?
Amniocentesis at 16+ weeks
How do you genetically test the blood?
Fetal blood sampling at 18+ weeks
When can you test fetal DNA from maternal blood?
8 weeks +
What is a rather clever way of looking at chromosomes?
Array Comparative Genomic Hybridisation
What is a Mutation?
Can be defined by a genetic change that causes disease
What is a polymorphism?
Genetic variation that is not pre-se disease causing
What are single nucleotide polymorphisms?
Single base changes
What is a copy number variation?
Insertions or deletions of DNA segments
Describe a Mutation?
De-Novo
Bigger
Affects known gene
Previously reported in same phenptype
Describe a Polymorphism?
Normal parent has it
Smaller
“empty” genetic region
Previously reported as polymorphism
What is FISH?
For when your missing bit of chromosome is too small to see
When would you do aCGH or chromosomal analysis?
High risk of chromosomal trisomy on screening
Fetal abnormality on scanning
Parent has balanced chromosomal rearrangement
What would count as fetal abnormality on scanning?
Small sized, especially if symmetrical growth failure
Increased nuchal thickness
Structural malformation - e.g. brain or heart
How is Increased nuchal thickness screened for?
Ultrasound scan around 12 weeks
