3: Genetics and children Flashcards Preview

Child Health Week 3 2017/18 > 3: Genetics and children > Flashcards

Flashcards in 3: Genetics and children Deck (24):
1

How is information stored in genes?

Amino acid sequences

i.e DNA

2

In which arrangement do DNA strands bind together?

Anti-parallel

3

What is the sugar forming the backbone of

a) DNA

b) RNA?

a) 2-deoxyribose

b) Ribose

4

Which bases pair in DNA?

And in RNA?

A-T; C-G

A-U; C-G

5

DNA strands are bound to which proteins?

Histones

6

Tons of DNA strands combine to form what?

Chromosome

7

How many base pairs are there in the human genome?

3 000 000 000

3 billion

8

How many genes does each human have?

30 000

30 thousand

9

How many polymorphisms does each person have on average?

3 000 000

3 million

10

Which genetic testing technique is used to find

a) large changes affecting the entire genome (e.g extra chromosomes)

b) tiny changes affecting one or a few bases (e.g point mutation)?

a) Array genomic hybridisation (aCGH)

b) Next generation sequencing (NGS)

11

How does aCGH work?

Detects BIGGER changes (e.g big deletions, chromosome duplications)

Compare sample to control DNA and ask "Is there more or less DNA?"

12

If aCGH finds half as much DNA as the control, a ___ mutation has occurred.

deletion

13

If aCGH finds 50% more DNA than the control sample, a ___ mutation has occurred.

duplication

14

aCGH can only detect (balanced / unbalanced) chromosome changes.

unbalanced changes

15

Which genetic disorder is caused by a deletion in chromosome 22?

Digeorge syndrome

16

What are the symptoms of Digeorge syndrome?

Developmental delay

Vision / hearing problems

Mouth deformities e.g cleft palate

Congenital heart disease

Hypoparathyroidism causing seizures

17

Which genetic test is used to identify Digeorge syndrome?

Why?

aCGH

Picks up bigger genome changes (e.g deletions or duplications)

Digeorge syndrome is caused by a deletion in chromosome 22

18

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Name each type of mutation.           

 

Normal

Stop mutation

Missense mutation

Insertion mutation

Deletion mutation (out of frame >>>>)

Deletion mutation (in frame)

Triplet expansion mutation

19

When is NGS used?

Small changes to genome

e.g a mutation in one gene

20

What is an example of a disease which could be identified by NGS?

Kabuki makeup syndrome

wouldn't worry about remembering it

21

What does de novo mean?

An acquired mutation

Arising spontaneously in the patient

22

What is the percentage chance of finding a de novo mutation in a child with a developmental disorder?

> 30%

23

For children with non-specific developmental disorders, which genetic test should be done first?

NGS

to try and find a small mutation

24

Although genetic tests are useful in diagnosing disease, what information is essential?

History

Examination

because there are too many genes to analyse