Cytogenetics and Aneuploidy Flashcards
Trisomy 21
Trisomy 13
Trisomy 18
The only trisomies compatible with live birth
13, 18, and 21
Klinefelter Syndrome
XXY Syndrome
Turner Syndrome
XO
The only monosomy compatible with life. Often diagnosed when female patients fail to go into puberty or have gonadal failure. ~1/2000 births
Short stature as a result of haploinsufficiency of SHOX.
Aneuploidy is the result of ____% of miscarriages.
Aneuploidy is the result of >60% of miscarriages.
5p-
Cri du Chat Syndrome
Missing the short arm of chromosome 5 on one copy.
Philidelphia chromosome karyotype
Translocation between chromosome 9 and 22.
Causative for chronic myelogenous leukemia (CML)
Nonallelic homologous recombination
NAHR duplication and deletion pair for PMP22
Pericentric Inversions
Span a centromere
The type that you may see in clinic.
Often result in haploinsufficiency of certain genes and triplicate copies of others.
Paracentric Inversions
Do not span a centromere
Either lead to normal chromosomes or extremely unstable chromosomes that will not give gametes.
Ring Chromosomes
Due to homology at ends (likely telomeres)
Cuts off the very ends of the chromosome and creates a ring structure with one centromere.
Balanced Translocation
Likely will go unnoticed in the proband, but descendants are likely to have dosage abnormalities.