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Flashcards in Mutations and Genetic Analysis Deck (83)
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1

What are the different kinds of chromosomal abnormalities?

Numerical

Structural

Mutational

2

When does first trimester begin and end?

First day of someone's last period and lasts until the end of week 12 of an embryo's life

3

What percentage of miscarriages during the first trimester are due to chromosomal abnormalities?

50%

4

What are the kinds of numerical abnormalities?

Trisomy (additional chromosomes)

Monosomy (less chromosomes)

5

What is trisomy?

Additional chromosomes

6

What is monosomy?

Less chromosomes

7

What are examples of trisomy?

Patau syndrome (additional 13)

Edwards syndrome (additional 18)

Downs syndrome (additional 21)

Klinefelter (boys have additional X)

8

Patau syndrome is an additional what chromosome?

13

9

Edwards syndrome is an additional what chromosome?

18

10

Downs syndrome is an additional what chromosome?

21

11

Klinefelter syndrome is an additional what chromosome?

Boys have an additional X chromosome

12

What is an example of a monosomy?

Turner's syndrome (female missing all or part of X chromosome)

13

What chromosome is missing in turner's syndrome?

Female missing all or part of X chromosome

14

What is disomy?

The condition of having a chromosome represented twice in a chromosomal complaint

15

What is aneuploudy?

The presence of an abnormal amount of chromosomes in a cell

16

What is nondisjunction?

Failure of chromosomes to seperate properly during cell division

17

What may the origin of nondysjunction be?

Paternal or maternal, with different kinds of trisomys having different likeliness of each

Most autosomal are maternal and sex monosomy sex linked is paternal and trisomy sex linked is even

18

What are examples of autosomal chromosomes aneuploidy syndromes?

Down syndrome (trisomy 21)

Patau syndrome (trisomy 13)

Edwards syndrome (trisomy 18)

19

What are the chances of inheriting trisomy 21 (down syndrome)?

1/650

20

What causes the chances of inheriting down syndrome to increase?

Increases with maternal age

21

What are some characteristics of down syndrome?

Facial dysmorphologies (birth defects that affect anatomy)

IQ less than 50

Alzheimer's disease in later life

22

What is down syndrome normally due to?

Non-dysjunction of chromosome 21 which is usually maternal (95%)

Translocation (5%)

23

What is the occurance of trisomy 13 (patau syndrome)?

1/1000

24

What are some characteristics of patau syndrome?

Multiple dysmorphic features and mental retardnation

Very few survive beyond first year

25

What is patau syndrome normally caused by?

Nondysjunction of chromosome 13 (90%)

Translocation (10%)

26

What is the occurance of trisomy 18 (edwards syndrome)?

1/3000

27

What are some characteristics of edwards syndrome?

Severe developmental problems

Most die in first year

28

What is edwards syndrome normally caused by?

Nondysjunction (90%)

29

What are some sex chromosomes aneuploidy syndromes?

Turner's syndrome (45, X)

Klinefelter syndrome (47, XXY)

30

What is the occurance of turner's syndrome?

1/5000