Genetics Flashcards

1
Q

What is personalised medicine?

A

The idea to use some form of testing to identify a subgroup of patients who respond to treatmet involving genetic testing and understanding molceular pathways

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2
Q

What does personlaised medicine allow you to do?

A

Separate patients into subgroups of those who will benefit frmo a treatment and exclude those who won’t or will have severe side effects

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3
Q

What clinical signs can be seen in the nails in tuberous sclerosis?

A

Periungual fibromata

Longitudinal ridging

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4
Q

What is a genodermatoses?

A

A skin condition caused by a genetic cause

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5
Q

How can tuberous sclerosis present in infants?

A

Infantile seizures

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6
Q

What is the earlisest cutaenous sign of tuberous sclerosis?

A

Ash-lead macule

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7
Q

What are all the clinical signs of tuberous sclerosis?

A
Periungual fibromas 
Facial angiofibromas 
Seizures due to tumours in the cortical brain 
Hamaromas - angiomyolipomas 
Bone cysts 
Shagreen patches
Enamel pitting
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8
Q

What are angiofibromas often misdiagnosed as?

A

Acne (erythematous papules) but the defining difference as angiofibromas don’t have comedones

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9
Q

What type of inheritance does tuberous sclerosis show?

A

Autosomal dominant - denovo mutations are common

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10
Q

What chromosomes are affected in tuberous sclerosis?

A

Chromosome 9 and 16

TSC1 and TSC2 which code for tuberin and hamartin

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11
Q

What is the chance of passing on a mutation to offspring in classical autosomal dominance?

A

50-50 chance

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12
Q

What are the different mutation types?

A
Missence
Deletion (in frame) 
Nonsense (premature stop codon) 
Deletion (frameshift) 
Altered splice site
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13
Q

For what conditions is using genetics the most useful in treatment of diseases?

A

In high penetrance disorders due to the fact that they tend to have one pathway and therefore one drug which can control it

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14
Q

What is genetic heterogeneity?

A

Mutations at two or more genetic loci that produce the same or similar phenotypes

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15
Q

What is disease expression variability?

A

Different people are affeced differently - even within the same family

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16
Q

What is epidermolysis bullosa (EB)?

A

A group of genetic skin fragility conditions that can range for very mild blistering to extensive skin loss with any movement or touching of the skin

17
Q

What are the three types of EB?

A

Simplex
Junctional
Dystrophic

18
Q

What is simplex epipdermolysis bullosa?

A

Split occurs within the epidermis - mildest form

19
Q

What is junctional epidermolysis bullosa?

A

Split occurs within the DEJ

20
Q

What is dystrophic epidermolysis bullosa?

A

Split occurs within the dermis of the skin - complicatd by scarring

21
Q

How many genes are involved in epidermolysis bullosa?

A

10 genes

22
Q

How many different types of keratin are there?

A

2 types - type 1 and type 2

Both are needed for proper structure of the skin

23
Q

What is haploinsufficiency?

A

Only one working copy of the gene - therefore there is reduced protein production

24
Q

What is dominant negative?

A

Expression of abnormal protein interferes with normal protein function

25
Q

What is gain of function?

A

Mutant protein gains a new function, affecting cell processes

26
Q

What is complete loss of protein?

A

Autosomal recessive - 2 faulty copies of gene produces no protein at all

27
Q

What is the risk of passing a mutation to an offspring if the gene is recessive?

A

1 in 4 risk of an affected child if the parents are both carriers

28
Q

How many cafe au lait patches are required on the skin to suggest a genetic disease?

A

More than 5

29
Q

What are the clinical signs of neurofibromatosis type 1?

A
Cafe-au lait macules 
Neurofibromas 
Plexiform neuroma
Axillary or ingunal freckling 
Optic glioma
Lisch nodules
Distinctive bony lesion
30
Q

What is the neurofibromine pathway involved in?

A

Controls transcription factors for cell growth, specifically Raf, MEK and ERK

31
Q

What are the genetic factors involved in skin barrier function failure in eczema?

A

Filaggrin

32
Q

What are the genetic factors involved in immunology in eczema?

A

IL-4 and IL-13

33
Q

What condition will filaggrin mutations cause?

A

Ichthyosis vulgaris

34
Q

Histologically what is absent in ichthyosis vulgaris?

A

Keratihyaline granules containing pro-filaggrin granules