Assessment and Screening

Question 1

Assessment of a patient in the genetics clinic involves looking for dysmorphic features. Give examples of these dysmorphic features.

Answer 1

macro or microcephaly
palpebral fissures
eye spacing
ear size, shape, position and rotation
nose size and nares
philtrum
mouth size, lips and teeth
limb proportion
skin lumps or abnormal pigmentation
palmar creases
correct number of fingers and toes

Question 2

What dysmorphic features are present in Rubinstein taybi syndrome?

Answer 2

Down slanting palpebral fissures
Microcephaly
Broad thumbs and toes

Question 3

Describe the process of PGD.

Answer 3

Involves the removal of one or sometimes two cells from an embryo of 3 days old which is in the blastomere stage and contains 6-10 cells
Then QF-PCR or FISH to look for mutations
Then unaffected embryos can be inserted into the uterus

Question 4

How successful is pre-implantation diagnosis?

Answer 4

50% chance of working once a healthy embryo has been acquired

Question 5

What factors could inhibit pre-implantation diagnosis?

Answer 5

Age

AMH level

Question 6

What is sensitivity?

Answer 6

The number of true positives divided by the total number of affected people

Question 7

What is specificity?

Answer 7

The number of true negatives divided by the total number of unaffected people

Question 8

What technique is used for neonatal screening of phenylketonuria and MCADD?

Answer 8

Mass spectrometry

Question 9

What technique is used for neonatal screening of congenital hypothyroidism and cystic fibrosis?

Answer 9

Immunoassays

Question 10

What technique is used for neonatal screening of sickle cell disorder?

Answer 10

HPLC

Question 11

What group of people are offered postnatal screening for tay Sachs disease?

Answer 11

Jewish people

Question 12

What prenatal genetic diagnostic test can be done in the first trimester?

Answer 12

Chorionic villus sampling

Question 13

What prenatal genetic diagnostic test can be done in the second trimester?

Answer 13

Amniocentesis

Question 14

There is a risk of miscarriage associated with CVS and amniocentesis. Which technique carries the biggest risk for miscarriage?

Answer 14

CVS

Question 15

Non-invasive prenatal diagnostic tests can be done privately to test for Down syndrome. What conditions might this technique be sued to detect in future?

Answer 15

Achondroplasia

Sex determination for x linked conditions

Question 16

It is possible to detect paternal mutations present in the mothers blood through what genetic diagnostic test?

Answer 16

Non-invasive prenatal diagnostic testing

Question 17

In the future next generation sequencing of whole exams will be available. How will current knowledge need to change to accommodate this?

Answer 17

We will need a better understanding of variants of uncertain significance and non-coding regions of the genome

Question 18

How will genetics shape personalised medicine in the future?

Answer 18

Increased efficacy and safety of prescribing based on analysis of patient’s SNPs
May become possible to tailor treatment to a specific disease causing mutation

Question 19

The advance of genetics will allow the further development of tailored treatments of specific disease causing mutations. What drug is currently used in cystic fibrosis patients with the G551D mutation?

Answer 19

Ivacaftor

Question 20

What mutation specific drug is current used against certain lung cancers?

Answer 20

Gefitinib

Question 21

What mutation specific drug is used against breast cancers with the HER2 mutation?

Answer 21

Trastuzumab

Question 22

The technique of exon skipping may be sued in the future to treat Duchenne’s muscular dystrophy. How does this technique work?

Answer 22

It alters splicing patterns in order to correct the reading frame and convert DMD into the less severe BMD phenotype

Question 23

Give examples of drugs which permit read-through of premature stop codons.

Answer 23

Ataluren

PTC124

Question 24

Base editing is a possible future technique for treating genetic conditions. Give an example of a condition which this technique could treat.

Answer 24

Convert G back to an A in beta thalassaemia in embryos

Question 25

There is a potential for off-target sites to be affected by CRISPR-CAS9 gene therapy techniques. T/F?

Answer 25

True