Genetics

Question 1

Sense mutation

Answer 1

The amino acid is not altered

Question 2

Missense mutation

Answer 2

Alters the amino acid sequence

Question 3

Mutation in Sickel cell anaemia

Answer 3

Substitution

GAG to GTG (Glu- Val)

Question 4

Mutation in HD and Fragile X

Answer 4

Insertion

Trinucleotide repeats

Question 5

22q11.2 deletion Syndrome

Answer 5

Clef Palate, heart defects, autoimmune disorders

Question 6

Trisomy 13

Answer 6

Patau

Question 7

Trisomy 18

Answer 7

Edwards

Question 8

Monosomy X in women

Answer 8

Turners

Question 9

Disomy X in men

Answer 9

Klinefelters

Question 10

Hereditary haemochromatosis inheritance?

Answer 10

Autosomal recessive

Question 11

2 examples of Imprinting Disorders

Answer 11

Pader Willi and Angelman Syndrome

Question 12

What is an imprinting disorder?

Answer 12

• If one parent’s gene is expressed and the other is ‘silenced’

Question 13

What is a karyotype?

Answer 13

Gives you a picture of someone’s chromosomes

Question 14

When is FISH used?

Answer 14

When a patient has features which are confident with a well-described micro deletion or micro duplication syndrome

Question 15

When is quantitative fluorescence PCR used?

Answer 15

• To count/quantify specific chromosomes

- Usually used for trisomies

Question 16

When is Array CGH used?

Answer 16

-Detects chromosome deletions and duplications but not structural chromosomal changes

Question 17

Calculating risk in recession conditions when individual has a sibling affected by the recessive condition

Answer 17

2/3 (sibling affected)
x
1/24 (general population risk)
x
1/4 (autosomal recessive)

Question 18

Example of a condition with genetic anticipation

Answer 18

HD

Question 19

When to do CVS

Answer 19

11.5wks

Question 20

When to do amniocentesis

Answer 20

15wks

Question 21

47XY + 13
Bilateral clef palate
Post-axial polydactyly
Holoprosencephaly (facial defects)

Answer 21

Patau Syndrome

Question 22

45,X

Neck webbing and oedema

Answer 22

Turner Syndrome

Question 23

What would aCGH look like in the parent with a balanced translocation?

Answer 23

Normal

aCGH only detects imbalance

Question 24

A diagnosis may be suspected, which test?

Answer 24

Chromosome analysis or array CGH

Question 25

You need to know the diagnosis (strong clinical feat, which test?

Answer 25

FISH

Question 26

Which weeks to detect the following on US:

• Cardiac
• Microcephaly
• Short limbs

Answer 26

• Cardiac 12-20wks
• Microcephaly usually after 22weeks
• Short limbs usually after 22wks