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Reproduction Week 5 2018/19 > 8: Genetics 2 > Flashcards

Flashcards in 8: Genetics 2 Deck (25)
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1

By which method can you check the whole genome for balanced mutations only?

Array CGH

2

What are some examples of balanced chromosomal mutations?

Deletions

Duplications

3

Apart from genetic testing, how else can you detect genetic diseases in a foetus?

Ultrasound

performed at 12 and 20 weeks

4

What is trisomy 13 called?

Patau syndrome

Incompatible with life in most causes - lots of birth defects, failure of one or both eyes to develop (cylopsia)

5

What are two common causes of intra-uterine growth restriction (IUGR)?

Chromosomal abnormality

Placental insufficiency

6

Which causes of IUGR result in

a) symmetrical growth restriction

b) asymmetrical growth restriction?

a) Symmetrical IUGR suggests GENETIC DISORDER

b) Asymmetrical IUGR suggests PLACENTAL INSUFFICIENCY

7

What is the appearance of asymmetrical IUGR secondary to placental insufficiency?

Why?

Enlarged head; smaller trunk and limbs

Brain growth prioritised

8

What is the mode of inheritance of Duchenne muscular dystrophy?

X-linked recessive

9

A woman carrying the recessive dystrophin mutation and an asymptomatic male have a child.

What is the percentage chance of them having an

a) affected child

b) affected boy?

a) 25% (recessive)

b) 50% (X-linked recessive, so can only be inherited by boys)

10

What is the percentage risk that a child will inherit a

a) autosomal dominant

b) autosominal recessive disorder?

a) 50%

b) 25%

11

The chances of a child inheriting an autosomal recessive disease is 25%.

In which group is this risk increased?

Consanguineous offspring

inbreeding

12

Which percentage of foetuses have a congential disease?

0.05%

Relatively uncommon

13

Which percentage of embryos have a genetic error before implantation?

50%

14

Which method of genetic testing is the best for identifying a known gene mutation in a foetus?

NIPT

i.e taking a maternal blood sample and looking for foetal DNA

also useful for sex determination

15

In cases of X-linked recessive disorders like DMD, why is non-invasive prenatal testing useful?

If NIPT identifies no Y chromosomes i.e it's a girl, you can stop worrying because DMD is inherited by males only

16

Which form of genetic testing involves work on embryos isolated from a woman?

Pre-implantation genetic diagnosis

17

Pre-implantation genetic diagnosis (PGD) is often combined with which assisted conception therapies?

IVF

ICSI

18

Which genetic analysis technique allows you to visualise the sex chromosomes of an embryo and thereby determine if it's a boy or girl?

FISH

One of its few remaining uses - fluorescent probes

19

What are the different names for the cell mass in the first days of embryogenesis?

Zygote

2 cell mass

4 cell mass

8 cell mass

Morula

Blastocyst

20

From which stage of the embryo are cells taken for PIGD?

8 cell stage

21

What is the success rate ("take-home rate") of IVF?

30%

Which can be difficult for the parents to accept

22

What is a major risk of IVF, which is avoided by not overstimulating the ovaries?

Multiple pregnancy

23

Which genetic disorders are caused by

a) trisomy 13

b) trisomy 18

c) trisomy 21?

a) Patau syndrome

b) Edwards' syndrome

c) Down's syndrome

24

revise week 5 endocrine and ivf process

25

genetics terminology - come back to this, lots more to learn