Genetics Flashcards

1
Q

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

A

Consanguinity

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2
Q

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

A

diamond

P

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3
Q

How do you represent twins on a pedigree chart?

A

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

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4
Q

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

A

23 chromosomes, 23000 genes, 3.3 billion base pairs

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5
Q

Mitochondrial inheritance is passed how?

A

exclusively maternal

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6
Q

Example of cytogenetic testing?

A

FISH testing

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7
Q

Example of Molecular testing

A

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

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8
Q

What is array CGH? what is it used for?

A

microarray comparative genome hybridisation

Used for chromosomal microdeletions

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9
Q

Features of Down’s Syndrome?

A
Single palmar crease
Clustered facial features
Stubby digits
Small ears
Slightly slanted eyes
Sparce hair
hypotonia
Large tongue
Small nose
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10
Q

What does nondisjunction mean in regards to cell division?

A

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

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11
Q

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

A

Translocation of 21 onto 14 in mothers haploid

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12
Q

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

A
trisomy = less than 1%
Translocation = 50%
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13
Q

What trisomy causes Patau?

A

13

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14
Q

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

A

Hypotelorism - front of brain fused

Seizures

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15
Q

What defects does an individual with Patau syndrome suffer from?

A
Seizures
Heart defect
Renal dysplasia
IUGR
Polydactyly
Early death
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16
Q

Where is the DiGeorge microdeletion and how is it diagnosed?

A

22q11 deletion diagnosed with microarray

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17
Q

What abnormalities do people with DiGeorge usually suffer from?

A
Cardiac abnormalities
Thymus hypoplasia - hypocalcaemia, t cell dysfunction, infection
Small chin
Weird lips
Broad nasal base
Cleft palate
Small sticky out ears
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18
Q

47 XXY? 47 X? Trisomy 18?

A

Kleinefelter
Turner
Edwards

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19
Q

Williams Syndrome deletion? what heart defect?

A

7q11 - supravalvular ventricular stenosis

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20
Q

Prader-Willi deletion?

A

15q11

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21
Q

Difference between Prader Willi and Angelman Syndrome?

A

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

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22
Q

List 6 types of gene disorder transmission?

A

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

23
Q

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?

A

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

24
Q

2 specialties that need to see individuals with Marfans

A

cardiology and ophthalmology

25
Q

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

A

Sartans

26
Q

What chromosome is effected in NF1?

A

17

27
Q

What are 3 signs of NF1?

A

Macrocephaly, cafe au lait spots, lisch nodules

28
Q

What chromosome is NF2 found on?

A

22

29
Q

What is NF2 associated with?

A

meningiomas, schwannomas

30
Q

Tuberous sclerosis is associated with what presentation?

A

Ash leaf hypopigmentation
Facial angiofibromas
Epilepsy
Cortical tumours

31
Q

What does the term anticipation refer to in Huntingtons Disease?

A

Gets worse throughout the generations

32
Q

How many triplet repeats are enough to cause Huntingtons

A

35 and above

33
Q

What chromosome is effected in Huntington’s?

A

4

34
Q

Name 3 conditions that are caused by triplet repeat expansions?

A

Huntingtons
Myotonic dystrophy
spinocerebellar ataxia

35
Q

What blood test will be very abnormal in DMD?

A

Very high CK

36
Q

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

A

Muscle biopsy looking for dystrophin protein

37
Q

Gower Manoeuvre in DMD?

A

crawl, use hands to prop up, grasp onto knees

38
Q

Features of FAS?

A
thin upper lip
small palpebral fissures
small nose
small mouth
prominent veins
learning difficulties
Smooth long philtrum
39
Q

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

A

Early in pregnancy effects physical appearance

Late in pregnancy effects cognitive development

40
Q

Which vitamin is teratogenic in pregnancy?

A

Vitamin A

41
Q

Whcih anticoagulant is teratogenic in pregnancy?

A

Warfarin

42
Q

What does contiguous gene inheritance refer to?

A

duplications or deletions of multiple genes on a chromosome

43
Q

What is achondroplasia the most common cause of?

A

Dwarfism

44
Q

What are the shape of the vertebrae in achondroplasia?

A

Bullet shape

45
Q

Osteogenesis imperfecta?

A

numerous fractures, IUGR, wormian bones

46
Q

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

A

Brushfield

47
Q

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

A

Xray and double bubble

Polyhydramnios

48
Q

Most common heart defect in Down Syndrome?

A

AVSD

49
Q

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

A

Balanced Robertsonian translocation

50
Q

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

A
OT
SLT
Opthalmology
ENT - hearing
Child development team
Cardiology
51
Q

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

A

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

52
Q

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

A

Hypothyroidism

Coeliac disease

53
Q

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

A

Early onset Alzheimers
Obstructive sleep apnoea
Atlantoaxial instability