Cytogenetics Articles Flashcards
At what age is amniocentesis routinely recommended and why?
At maternal age 35, as the risk of trisomy at this age (1:270) approximately matches the risk of miscarriage due to amniocentesis (1:200).
Review: How are biochemical markers shifted in down syndrome and edward syndrome?
Down: -AFP, -UE3, +hCG
Edwards: -AFP, -UE3, -hCG
What genetic feature do Fanconi anemia, Bloom syndrome, and ataxia telangiectasia have in common?
All result in increased chromosome breakage (eg abnormalities of DNA repair mechanisms)
Describe spectral karyotyping.
eg. M-FISH or SKY method; allows for tagging of all chromsomes simultaneously with different fluorescent probes. Used when conventional methods cannot identify chromosomes.
How does mosaicism arise?
Chromosomal change that occurs during embryonic development, resulting in two or more “clones” or lineages of cells.