L12 -diagnosing gentic disease

Question 1

why is chr study imp

Answer 1

chr abn cause infertility and recurrent miscarriage

>50% of spontaneous abortion inthe first trimester ar the result of chr abn

Question 2

what is polyploidy

Answer 2

numerical abn

inc triploidy - extra of each chr

Question 3

what cause triploidy

Answer 3

2 sperm one egg

diploid egg

Question 4

consequence of triploidy

Answer 4

v rare go to term

norm spontaneous abort

Question 5

what is aneuploidy

Answer 5

one or more ind chr extra/missing

Question 6

what is monosomy and consequence

Answer 6

lack of a chr

lethal in autosome

Question 7

what is trisomy and consequence

Answer 7

extra copy of a chr
lead to early miscarriage
chr 11/18/21 sruvive to term

Question 8

what eg of a sex chr aneupolidy

Answer 8

klinefelter

Question 9

eg of a autosome aneuploidy

Answer 9

down syndrome

70% abort naturally

Question 10

eg of a disease caused by chr abn of del

Answer 10

prader willi syndrome
15q11 pat del (and not expr by mat)
7 gene del
foodseek behav /obesity

Question 11

disease eg of chr abn of insertion

Answer 11

7q11.23 = dup of 28 genes

deep set eyes/long nose/speech dyspraxa

Question 12

what is a ring chr

Answer 12

mut event removes both telomeres
repair by fuse ends together
ring chr 20 assoc with epilepsy

Question 13

how commmon are chr tanslocations

Answer 13

1:500

Question 14

what the adv of karyotpye

Answer 14

whole genome
gross abn detect
cells from various tissues can be used

Question 15

disadv of karyotype

Answer 15

limited resolution >5mb 
slow 
relative £
skill to interpret 
cant detect unbal rearr

Question 16

describe karyotpe

Answer 16

look at gtg bind patterns

Question 17

what the adv of FISH

Answer 17

detect small rearr 
>0.5mb
high res
cheap
easy to interpret
can use mutiple probes 
can study metaphase chr or interphase nuclei

Question 18

what the disadv of FISH

Answer 18

have to know where to look

Question 19

what disease FISH detect

Answer 19

Williams sybdrome
norm karyotpe
FISH shown 1.5mb del on 7q11.23

Question 20

what the adv of aCGH

Answer 20

whole genome or any targeted chr
quantitative ata on dup and del
cheap
can get good res

Question 21

disadv of aCGH

Answer 21

cant detect bal rearrrangements

no info on location of extra info

Question 22

the mech used to validate findings of microarray

Answer 22

qPCR - res down to 100bp / cheap/quick
MLPA
tiled oligonuc microarray

Question 23

how can a balced abn give ptype

Answer 23

pot unequal loss/gain of genes

breakpoints disrupt gene or sep from reg element