chromosome abnormalities

Question 1

a chromosome abnormality

Answer 1

is a change in structure/number of the chromosomes

Question 2

what are the 2 kinds of chromosome abnormalities

Answer 2

costitutive - from birth

acquired/somatic - after birth

Question 3

how can chromosome abnormalities be found?

Answer 3

by karyotyping but only if their length is above 5-10Mb

Question 4

Chromosome instability is present at

Answer 4

the cleavage state embryo

Question 5

chromosome instability is unaffected by

Answer 5

ethnicity and geographical origin, meaning it is a trait of human reproduction

Question 6

are all abnormalities pathogenic?

Answer 6

it depends on if they are balanced (if yes then no phenotype), and on the extension of the anomaly

Question 7

what are the 2 classifications of chromosome abnormalities

Answer 7

numeric and structural

Question 8

polyploidy

Answer 8

more than 2 pairs of homologs( sets of chromosomes). Can be triploidy, and tetraploidy

Question 9

aneuploidy

Answer 9

refers to an anomaly referring to a single chromosome. Can be trisomy, tetrasomy, monososomy

Question 10

how can we have a triploid human genome?

Answer 10

~double fertilization
~fertilization of a 2n egg
~fertilization of an egg by a 2n sperm

Question 11

how can we have a tetraploid human genome

Answer 11

by endomitosis: DNA duplication is not followed by cell division

Question 12

how can we have an aneuploidy

Answer 12

~non-disjunction during meiosis 1- 4 aberrant gametes
~non-disjunction during meiosis 2- 2 aberrant gametes
~non-disjunction during mitosis - fetus will be a mosaic if this occurs during cleavage stage

Question 13

monosomy

Answer 13

is the absence of one autosome, ALWAYS LETHAL

Question 14

Patau syndrome

Answer 14

trisomy of chromosome 13

Question 15

Edwards syndrome

Answer 15

trisomy of chromosome 18

Question 16

warkany syndrome

Answer 16

trisomy of chromosome 8

Question 17

down syndrome

Answer 17

trisomy of chromosome 21

Question 18

turner syndrome

Answer 18

is a female with only one X

Question 19

klinfelter syndrome

Answer 19

male with extra X

Question 20

terminal deletion

Answer 20

deletion at the end of a chromosome

Question 21

interstitial deletion

Answer 21

deletion within a chromosome

Question 22

micro-deletion

Answer 22

a small deletion up to 5 Mb

Question 23

direct duplication

Answer 23

if the duplicated region maintains the same direction as the original

Question 24

inverted duplication

Answer 24

is the duplicated region is opposite direction as the original

Question 25

reciprocal translocations

Answer 25

genetic material is exchanged between 2 non-homologous chromosomes

Question 26

robertsonian translocations

Answer 26

are a subtype of reciprocal translocations involving acrocentric chromosomes. The reciprocal changes results in one large metacentric chromosome, one extremely small chromosome

Question 27

paracentric inversions

Answer 27

when the inversion does not involve the centromere

Question 28

pericentric inversion

Answer 28

when the inversion does involve the centromere

Question 29

a single break in a chromosome will produce

Answer 29

a terminal deletion