Genetics

Question 1

Which procedure is needed to get tissue from the placenta?

Answer 1

Chorionic villus biopsy

Question 2

Which procedure is needed to get tissue from foetal skin/urine cells?

Answer 2

Amniocentesis

Question 3

From what time of gestation can CVS be performed?

Answer 3

11.5 weeks

Question 4

From what time of gestation can amniocentesis be performed?

Answer 4

15 weeks

Question 5

Which technique can sequence a whole genome?

Answer 5

Array CGH

Question 6

Which technique targets a specific part of the genome?

Answer 6

Fluorescence in-situ hybridisation (FISH)

Question 7

What is the main difference between a mutation and polymorphism?

Answer 7

A mutation is a genetic change that causes disease, a polymorphism (per-se) does not

Question 8

Give some characteristics of mutations

Answer 8

De-novo
Affects known gene
Reported in same phenoytpe

Question 9

Give some characteristics of polymorphisms

Answer 9

Normal parent has it

Affects “empty” genetic region

Question 10

When is FISH used?

Answer 10

When the missing bit of chromosome is too small to be picked up

Question 11

When is prenatal genetic screening done in Scotland?

Answer 11

12, 16 and 20 weeks

Question 12

What prenatal genetic screening is done at 16 weeks?

Answer 12

Maternal blood test to look for Down’s syndrome biochemical markers (NIPT)

Question 13

How does non-invasive prenatal testing for trisomy 21 work?

Answer 13

Random next-generation sequencing reads to detect if there are more reads from chromosome 21 than should be

Question 14

What clinical investigation is best to check for Down’s syndrome at 18 weeks gestation?

Answer 14

Amniocentesis

Question 15

What genetic investigation is best to check for Down’s syndrome at 18 weeks gestation?

Answer 15

Array CGH

Question 16

In a balanced chromosome rearrangement all the chromosomal material is present. True/false?

Answer 16

True

Question 17

What occurs in an unbalanced chromosome rearrangement?

Answer 17

There is extra or missing chromosomal material

Question 18

What occurs in Robertsonian translocation?

Answer 18

Two acrocentric chromosomes are stuck end to end

Question 19

What does a Robertsonian translocation increase risk of?

Answer 19

Trisomy

Question 20

In a parent with a balanced translocation, what would the aCGH look like?

Answer 20

Normal - only detects imbalance

Question 21

What occurs in a balanced reciprocal translocation?

Answer 21

There is an exchange of material between nonhomologous chromosomes

Question 22

What test is done to detect chromosome deletions/duplications?

Answer 22

Array CGH

Question 23

What is pre-implantation genetic diagnosis (PGD)?

Answer 23

When a genetic test is performed on an embryo before re-implanting one

Question 24

Give some advantages to PGD

Answer 24

Pregnancy less likely to be affected

Less likely to require TOP

Question 25

Give some disadvantages of PGD

Answer 25

Requires ICSI (expensive/invasive)
Emotional rollercoaster for parents
Multiple pregnancy risk

Question 26

When may parents consider PGD?

Answer 26

Parental chromosomal abnormality
X-linked disorder (re-implant female embryo)
Single gene disorder (CF/Huntington’s etc.)