Genetics

Question 1

On a pedigree chart what does the double line joining mean?

Answer 1

Consanguinity

Question 2

On a pedigree chart, if you are unsure on the sex what do you represent the individual as? what if they are in utero?

Answer 2

diamond

P

Question 3

How do you represent twins on a pedigree chart?

Answer 3

oblique line from generation above and joined with a double horizontal line

Question 4

How many chromosomes, genes and base pairs do we have in each cell?

Answer 4

23 chromosomes, 23000 genes, 3.3 billion base pairs

Question 5

Mitochondrial inheritance is passed how?

Answer 5

exclusively maternal

Question 6

Example of cytogenetic testing?

Answer 6

FISH testing

Question 7

Example of Molecular testing

Answer 7

DNA analysis - microarray, gene panels, exomes, whole genome

Question 8

What is array CGH? what is it used for?

Answer 8

microarray comparative genome hybridisation

Used for chromosomal microdeletions

Question 9

Features of Down’s Syndrome?

Answer 9

Single palmar crease
Clustered facial features
Stubby digits
Small ears
Slightly slanted eyes
Sparce hair
hypotonia
Large tongue
Small nose

Question 10

What does nondisjunction mean in regards to cell division?

Answer 10

When some chromosomes dont make it to the right side of the cell

Question 11

Apart from nondisjunction of chromosome 21, what is the other cause of Down’s Syndrome caused by abnormality in cell division?

Answer 11

Translocation of 21 onto 14 in mothers haploid

Question 12

What is risk of reoccurence in trisomy 21 vs translocation of 21

Answer 12

trisomy = less than 1%
Translocation = 50%

Question 13

What trisomy causes Patau?

Answer 13

13

Question 14

What brain abnormality occurs in Patau and how does this present at birth?

Answer 14

Hypotelorism - front of brain fused

Seizures

Question 15

What defects does an individual with Patau syndrome suffer from?

Answer 15

Seizures
Heart defect
Renal dysplasia
IUGR
Polydactyly
Early death

Question 16

Where is the DiGeorge microdeletion and how is it diagnosed?

Answer 16

22q11 deletion diagnosed with microarray

Question 17

What abnormalities do people with DiGeorge usually suffer from?

Answer 17

Cardiac abnormalities
Thymus hypoplasia - hypocalcaemia, t cell dysfunction, infection
Small chin
Weird lips
Broad nasal base
Cleft palate
Small sticky out ears

Question 18

47 XXY? 47 X? Trisomy 18?

Answer 18

Kleinefelter
Turner
Edwards

Question 19

Williams Syndrome deletion? what heart defect?

Answer 19

7q11 - supravalvular ventricular stenosis

Question 20

Prader-Willi deletion?

Answer 20

15q11

Question 21

Difference between Prader Willi and Angelman Syndrome?

Answer 21

Prader Willi is if its inherited from the male and Angelman is if its inherited from the female

Question 22

List 6 types of gene disorder transmission?

Answer 22

Autosomal dominant, recessive, xlinked dominant, recessive, y linked, mitochondrial

Question 23

Marfans:
Inheritance pattern?
What gene is effected? on what chromosome?
What do you measure between in Marfans to work out if there is a reduced ratio?
Features?

Answer 23

autosomal dominant
fibrillin gene on chromosome 15 (FBN1)
Measure symphysis pubis to head and syphysis pubis to toes then ratio will be less than 0.8
Lax joints, arachnodactyly, ectopic lentis (blind), dissection of aorta, high arched palate

Question 24

2 specialties that need to see individuals with Marfans

Answer 24

cardiology and ophthalmology

Question 25

What drug class can partially protect against aortic aneurysm in Marfans?

Answer 25

Sartans

Question 26

What chromosome is effected in NF1?

Answer 26

17

Question 27

What are 3 signs of NF1?

Answer 27

Macrocephaly, cafe au lait spots, lisch nodules

Question 28

What chromosome is NF2 found on?

Answer 28

22

Question 29

What is NF2 associated with?

Answer 29

meningiomas, schwannomas

Question 30

Tuberous sclerosis is associated with what presentation?

Answer 30

Ash leaf hypopigmentation Facial angiofibromas Epilepsy Cortical tumours

Question 31

What does the term anticipation refer to in Huntingtons Disease?

Answer 31

Gets worse throughout the generations

Question 32

How many triplet repeats are enough to cause Huntingtons

Answer 32

35 and above

Question 33

What chromosome is effected in Huntington's?

Answer 33

4

Question 34

Name 3 conditions that are caused by triplet repeat expansions?

Answer 34

Huntingtons Myotonic dystrophy spinocerebellar ataxia

Question 35

What blood test will be very abnormal in DMD?

Answer 35

Very high CK

Question 36

What investigation will be needed in DMD? what is it looking for?

Answer 36

Muscle biopsy looking for dystrophin protein

Question 37

Gower Manoeuvre in DMD?

Answer 37

crawl, use hands to prop up, grasp onto knees

Question 38

Features of FAS?

Answer 38

``` thin upper lip small palpebral fissures small nose small mouth prominent veins learning difficulties Smooth long philtrum ```

Question 39

How does the trimester in pregnancy that you drink alcohol effect the cognitive and physical differences in FAP?

Answer 39

Early in pregnancy effects physical appearance | Late in pregnancy effects cognitive development

Question 40

Which vitamin is teratogenic in pregnancy?

Answer 40

Vitamin A

Question 41

Whcih anticoagulant is teratogenic in pregnancy?

Answer 41

Warfarin

Question 42

What does contiguous gene inheritance refer to?

Answer 42

duplications or deletions of multiple genes on a chromosome

Question 43

What is achondroplasia the most common cause of?

Answer 43

Dwarfism

Question 44

What are the shape of the vertebrae in achondroplasia?

Answer 44

Bullet shape

Question 45

Osteogenesis imperfecta?

Answer 45

numerous fractures, IUGR, wormian bones

Question 46

What is a symptom in the eyes of Down Syndrome children?

Answer 46

Brushfield

Question 47

Diagnosis for duodenal atresia and what is usually seen? What is there usually a history of?

Answer 47

Xray and double bubble | Polyhydramnios

Question 48

Most common heart defect in Down Syndrome?

Answer 48

AVSD

Question 49

What is the name of the mutation that can lead to Down Syndrome that is not resultant in trisomy 21?

Answer 49

Balanced Robertsonian translocation

Question 50

What departments do Down Syndrome children need to be referred to?

Answer 50

``` OT SLT Opthalmology ENT - hearing Child development team Cardiology ```

Question 51

Why do children in Down Syndrome suffer ear troubles? what ear troubles are common? How is this monitored?

Answer 51

Increased rate of middle ear infections Common to have both conductive and sensorineural deafness Routine ENT follow up

Question 52

What 2 conditions can develop in Down Syndrome patients and therefore screened for every 2 years?

Answer 52

Hypothyroidism | Coeliac disease

Question 53

Apart from leukaemia what are Down Syndrome patients more likely to suffer with?

Answer 53

Early onset Alzheimers Obstructive sleep apnoea Atlantoaxial instability