Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

5310 - Embryology > nonsyndromic HL > Flashcards

nonsyndromic HL Flashcards

1
Q

DFN

A

deafness neurosensory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

for non-syndromic conditions what is the most sensible guess if you don’t know the inheritance pattern

A

recessive as this is the majority of the inheritance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

non syndromic dominant conditions are identified by ____

A

DFNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

non syndromic recessive conditions are identified by ____

A

DFNB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

DFNB1A =

A

connexin 26

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

DFNB1B =

A

connexin 26

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the gene mutation of connexin 26

A

GJB2 gene mutation – Cx26
GJB6 gene mutation – Cx26

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what do modifier genes do for HL

A

modify severity of HL, making it worse or mild

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

why do we see differences in expressivity and penetrance with recessive disorders

A

modifier genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the primary mod of later onset nonsyndromic deafness

A

dominant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what do almost AD conditions show

A

post-lingual progressive HL but differ in :
-age of onset
-rate or progression
-ultimate degree of HL
-vestibular invovlement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

AD non-syndromic HL examples

A

otosclerosis and DFNA5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

otosclerosis

A

ossification of the stapes footplate and into the oval window
- incomplete penetrance and varying expressivity
-will commonly present as a complex genetic disorder
-genes affected cause abnormal bone metabolism but there are multiple genes that can be affected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is otosclerosis triggered by

A

combination of genetics, environmental, hormonal and other factors
-can often present within pregnant women due to hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

who is most vulnerable population for otosclerosis?

A

young white females - we don’t know why

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

pathogenesis of otosclerosis

A

a focal disease unique to the temporal bone
-disease of abnormal bone remodeling of the otic capsule
-no remodeling of the otic capsule occurs following embryologic development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

site of lesion of otosclerosis

A

otic capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

DFNA5

A

AD progressive SNHL
-HL is present in childhood and becomes worse with age

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

50% of AR non-syndromic HL is cuased by

A

connnexin 26 (GJB2 gene) mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what do AR conditions usually show

A

severe to profound SNHL that is pre-lingual in origin
-over 50% of AR HL is caused by connexin

21
Q

what is connexin

A

a protein found in the cells throughout the body
NOT found in the cochlear hair cells

22
Q

where can connexin 26 be found

A

The inner ear (including utricle & saccule - nonsensory epithelia)
Skin
Liver
Bladder
Placenta
Breast
Brain

23
Q

where is connexin 26 not found

A

not found in the cochlear hair cells

24
Q

what is the gene for connexin

A

GJB
GJB2, GJB6,

25
Q

what is the protein product of GJB2

A

connexin 26 (Cx26)

26
Q

what is the protein product of GJB6

A

connexin 30 (Cx30)

27
Q

what is the best management for connexin?

A

CI

28
Q

what does the gap junction do in terms of connexin

A

permits ion transfer between cytoplasm of cells
-when opens the potassium goes through
-when closed potassium does not go through

29
Q

what happens to the gap when connexin is mutated

A

the gap junctions will not open or close which results in no regulation

30
Q

how does the mendelian law’s relate to connexin

A

second law (independent assortment) - separate genes for separate traits
-connexin is an example of how this law does not hold to be true due to the close relation of the genes for connexin 26 and 30 one can influence the expression of the other

31
Q

2nd law remidner card

A

law of independent assortment
-separate genes for separate traits are passed from parents to offspring independently of one another
-biological selection of one gene has nothing to do with the selection of the other gene

32
Q

connexin’s structures

A

hexagonal array of proteins within the membrane of each cell that when lined up together can create a gap junction
-groups of 6 and wrapped around the connexon

33
Q

what connexin proteins are involved in deafness

A
  • Cx26 (DFNB1/DFNA3) (most common)
  • Cx36
  • Cx30 (GJB6-DFNA3; also common)
  • Cx31
  • Cx32 (DFN or DFNX, X-linked Charcot-Marie-Tooth Disease)
34
Q

what is the most common allele mutation in connexin 26

A

35delG
-a frameshit mutation that will code for a different protein

35
Q

audiologic findings with connexin 26

A

congenital HL
-severity of HL can be mild to profound
-usually bilateral
-wide variability
-sudden HL can occur

36
Q

what else can occur with certain connexin phenotypes

A

skin diseases
-this is due to the protein being found throughout the body
-causes some patients to not be good CI candidates due to skin fragillity

37
Q

what is usually the best intervention for patients with Cx26

A

CIs
-speech intervention needs to occur as well

38
Q

x-linked non-syndromic HL examples

A

stapes fixation with perilymph gusher

39
Q

stapes fixation with perilymph gusher

A

occurs when you are born with the stapes footplate within the oval window
-gusher: occurs during surgery to fix stapes and perilymph leaks out causing sudden HL
-without the surgery, HL can be mixed or progressive

40
Q

mitochondrial non-syndromic HL examples

A

aminoglycoside induced ototoxicity

41
Q

amunoglycoside induced ototoxicity

A

occurs when certain people take doses of this group of antibiotics and it causes irreversible HL
-occurs due to a mutation and the problem arises with not knowing you have the mutation
-experience sudden onset severe/profound SNHL when exposed to this medication
-not dose dependent

42
Q

what are the 3 categories of genetic disease

A
  • complex genetic disorders
  • monogenic diseases
  • environmental diseases
43
Q

complex genetics

A

causes due to an interaction between genetics and the environment

44
Q

monogenic

A

primarily caused by genes
The environment only plays a minor role

45
Q

environmental diseases

A

you may have the disease but it wont manifest itself until environmental factors come into play

46
Q

why is there no clear inheritance pattern for complex genetics

A

becuase there are several different variants responsible for the disease

47
Q

what is an example of complex genetics

A

age related HL
-due to the root of the cause being hard to determine

48
Q

age-related HL

A

not every older adult will have HL
-could be due to genetics, environmental factors, social life aspects
-multiple genes at play
-there is no diagnostic value

49
Q

first & third recessive deafness (connexin deafness

A

DFNB1 & DFNB3

5310 - Embryology (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions