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Flashcards in genetics Deck (61):
1

do people who are low risk of hereditary cancer get additional screening

no - same risk as general public

2

how can people with BRAC1/2 genes lower their risk of breast cancer

prophylactic mastectomy

3

what are the main features of NF2

acoustic neuromas (usually bilateral)
CNS and spinal tumours
A few Café Au lait spots

4

what cancers are associated with HNPCC/ lynch

colorectal
endometrial
urinary tract
ovarian
gastric

5

ethically when should children or adolescents be genetically tested

if there are potential medical benefits

6

what is the biggest environmental trigger for disease

alcohol consumptions

7

how often should people with high risk HNPCC get a colonoscopy

2 yearly form 25

8

what is the management of suspect NF1 in a newborn

Annual review of affected individuals and at risk children until diagnosis can be excluded (5 years) or genetic test clarified
-Blood pressure -Spine for scolisosis
-Tibia for unusual angulation
- Visual acuity and visual fields
-Educational assessment - patient report unusual symptoms

9

why may adults be referred to genetics

Diagnosis understand why symptoms have occurred
Predictive testing – if at risk
Carrier testing or cascade screening – find risk to children
Family history (including cancer) – give opportunity of prevention
Fetal loss or recurrent miscarriages.

10

what is the appropriate follow up for people you suspect to have a hereditary cancer syndrome

curate risk assessment
effective genetic counselling
appropriate medical follow up

11

what is the diagnostic criteria for NF1

café au lait spots - 6 or more/big >1/2cm - neurofibromas - 2 or more
axillary freckling Lisch nodules (specks in iris, asymptomatic)
optic glioma (optic chiasm) - thinning of long bone cortex (false joint)
family history
(need +2)

12

which people may yo suspect a hereditary cancer syndrome in

¥ Cancer in 2 or more close relatives (on same side of family)
¥ Early age at diagnosis
¥ Multiple primary tumors
¥ Bilateral or multiple rare cancers
¥ Characteristic pattern of tumours (e.g. breast and ovary, endometrium and bowel)
¥ Evidence of autosomal dominant transmission

13

how is duchenne muscular dystrophy inherited

x linked

14

what kind of genes are mutated in HNPCC/ lynch

mismatch repair genes

15

describe the multistep carcinogenesis of colon cancer

normal epithelium
LOSS OF APC
hyper proliferative epithelium
early adenoma
ACTIVATION OF K-RAS
intermediate adenoma
LOSS OF 18Q
late adenoma
LOSS OF TP53
carcinoma
OTHER ALTERATIONS
metastasis

16

what chromosome is affected in NF2

chromosome 22

17

what are benefits of genetic testing

- Identifies highest risk
- Identifies non-carriers in families with a known mutation
- Allows early detection and prevention strategies
May relieve anxiety

18

what are some features of myotonic dystrophy

Bilateral late-onset cataract
Muscle weakness, stiffness & myotonia (characteristic)
Low motivation
facial weakness
bowel problems (IBS/ constipation
diabetes mellitus more common
Heart block – monitor as cause of unexpected death, treat with pacemaker
Death post-anaesthetic a risk if not monitored – respiratory compromise due to muscle weakness, monitor for much longer after surgery

19

are somatic mutations heritable

no

20

how often should people with moderate risk HNPCC get a colonoscopy

35 and 55

21

what are risks and limitations of genetic testing

- Does not detect all mutations
- Continued risk of sporadic cancer
- Efficacy of interventions variable
May result in psychosocial or economic harm

22

what makes myotonic dystrophy worse in each generation

anticipation (increasing repeats)

23

how many pairs of chromosomes are in the human genome

23
(~25,000)

24

how do tumours divide

uncontrollably

25

what age do people with lynch syndrome typically present

45 years

26

what sex is affected by X linked conditions

males

27

do AD mutations have skipped generations

no

28

do people who are medium risk of hereditary cancer get additional screening

yes - increased frequency

29

what gene is affected in Neurofibromatosis type 1

17q - tumour supressor gene

30

list some possible chromosomal models of inheritance

translocations
deletions/ micro deletion
numerical

31

what is the lifetime risk of breast cancer if you have the BRAC1/2 gene

60-80%

32

what mutation is seen in myotonic dystrophy

CTG repeat in chromosome 19, exhibits anticipation (increasing repeats) with increasing severity in each generation

33

what cancers are increased in males who have the BRAC2 gene

prostate
breast

34

name 3 diseases that have a genetic aetiology with germ line variations present in every cell (AD)

NF1
myotonic dystrophy
tuberous sclerosis

35

what genes cause tuberous sclerosis

TSC 1
TSC 2

36

do people who are high risk of hereditary cancer get additional screening

yes + gene testing

37

what are clinical features of tuberous sclerosis

learning difficulty
seizures
skin lesions - depigmented macules, angiofibromas (butterfly rash, raised areas, face/ around mouth), fibrous plaque forehead, shagreen patches, subungual fibromas (toenail groove, diagnostic aid)
Kidney - cysts and angiomyolipomata (can predispose to renal malignancy)
Phakomas in eye - benign unless on macula
Rhabdomyomas in heart – tumour of heart muscle

38

what is the lifetime risk of ovarian cancer if you have the BRAC1/2 gene

20-50%
BRAC1> BRAC2

39

what is the difference between a total (Simple) mastectomy and subcutaneous mastectomy

subcutaneous is nipple preserving

40

what are some minor features of neurofibromatosis type 1

Macrocephaly (big head) Short stature
Dysmorphic facial features- “Noonan look” - Epilepsy Scoliosis - Psuedoarthrosis of tibia (cyst– fracture prone)
Learning difficulties
Raised BP - due to renal artery stenosis or phaechromocytoma
Neoplasia - CNS (optic gliomas), endocrine tumours, sarcomatous changes

41

what are the 4 principles of ethics

respect for autonomy
non malificence
benificence
justice

42

what type of mutations cause cancer family syndromes

germline

43

if there is a germline mutation in a parents egg or sperm, how will it manifest in the child

all cells affected in offspring

44

when should people with FAP get their colon removed

30

45

to what degree of relative should relatives be referred to genetics

1- 1/2
2- 1/4
3- 1/8

46

how would you investigate tuberous sclerosis

Clinical examination – skin signs (UV woods lamp, nails), retinal examination
Cranial MR scan
Renal ultrasound – for angiomyolipomata
Echocardiogram – for rhabdomyomas

47

what sit the process of the genetic clinic for cancer

Obtain detailed family history-
Confirm diagnoses of cancer
Risk estimation – explain basis
Counselling
Interventions - Increased awareness of symptoms/ signs
Lifestyle – diet, smoking, oestrogen use
Screening
Prophylactic surgery
Genetic testing – consider in high risk

48

what is meant by a multifactorial etiological conditions

a polygeneic genetic component interacting with environmental factors

49

what are common problems in multi-system disease

variable expression within families
present to many different specialities
family history often missed

50

what type of tissue do somatic mutations occur in

non - germline

51

cancer genes are intragenic - what does this mean

associated with coding DNA

52

how does Li- fraumeni syndrome typically present in kids

soft tissue sarcoma

53

what tissues do germline mutations occur in

egg or sperm

54

is HNPCC AD or Ar

AD

55

what is meant by multistep carcinogenesis

accumulation of genetic damage causes tumour with metastatic potential

56

what is the classic triad of tuberous sclerosis

epilepsy, learning, difficulty, skin lesions

57

what is the difference between FAP and HNPCC

FAP - carpet of polyps in bowel
HNPCC - small number of polyps but still high chance of cancer

58

in autosomal dominant inheritance, what is the chance of inheriting the mutation

50%

59

Is BRAC AD or Ar

AD

60

what benign tumour is seen in many organs in tuberous sclerosis

hamartomas

61

give an example of a condition with multistep carcinogenisis

colon cancer