L12 -diagnosing gentic disease Flashcards
why is chr study imp
chr abn cause infertility and recurrent miscarriage
>50% of spontaneous abortion inthe first trimester ar the result of chr abn
what is polyploidy
numerical abn
inc triploidy - extra of each chr
what cause triploidy
2 sperm one egg
diploid egg
consequence of triploidy
v rare go to term
norm spontaneous abort
what is aneuploidy
one or more ind chr extra/missing
what is monosomy and consequence
lack of a chr
lethal in autosome
what is trisomy and consequence
extra copy of a chr
lead to early miscarriage
chr 11/18/21 sruvive to term
what eg of a sex chr aneupolidy
klinefelter
eg of a autosome aneuploidy
down syndrome
70% abort naturally
eg of a disease caused by chr abn of del
prader willi syndrome
15q11 pat del (and not expr by mat)
7 gene del
foodseek behav /obesity
disease eg of chr abn of insertion
7q11.23 = dup of 28 genes
deep set eyes/long nose/speech dyspraxa
what is a ring chr
mut event removes both telomeres
repair by fuse ends together
ring chr 20 assoc with epilepsy
how commmon are chr tanslocations
1:500
what the adv of karyotpye
whole genome
gross abn detect
cells from various tissues can be used
disadv of karyotype
limited resolution >5mb slow relative £ skill to interpret cant detect unbal rearr
describe karyotpe
look at gtg bind patterns
what the adv of FISH
detect small rearr >0.5mb high res cheap easy to interpret can use mutiple probes can study metaphase chr or interphase nuclei
what the disadv of FISH
have to know where to look
what disease FISH detect
Williams sybdrome
norm karyotpe
FISH shown 1.5mb del on 7q11.23
what the adv of aCGH
whole genome or any targeted chr
quantitative ata on dup and del
cheap
can get good res
disadv of aCGH
cant detect bal rearrrangements
no info on location of extra info
the mech used to validate findings of microarray
qPCR - res down to 100bp / cheap/quick
MLPA
tiled oligonuc microarray
how can a balced abn give ptype
pot unequal loss/gain of genes
breakpoints disrupt gene or sep from reg element
