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oral histology > Human GEnetics of Amelogenesis Imperfecta > Flashcards

Human GEnetics of Amelogenesis Imperfecta Flashcards

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1
Q

why is Enamel unique

A

High mineral contenet

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2
Q

what are Proteins used for in Enamel

A

Enamel formation but not for the final product

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3
Q

what cleaves enamel structural proteins and when

A

Proteinase soon after secretion into the matrix

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4
Q

where do Enammel Cristals grow longer

A

At the enamel surface

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5
Q

where do Enamel crystals grow thicker

A

At the depth

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6
Q

Stages of Dental Enamel formation

A

Secretory stage

Maturations

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7
Q

what happens in the Secretory stage

A

Ameloblasts secrete enamel matrix to fill the full enamel thickness

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8
Q

what happens in the Maturation stage

A

Degradation of enamel matrix and mineralization

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9
Q

what do Ameloblasts develop in the secretory stage to help with secretion of enamel matrix

A

trianglular shape at the distal end that remains in the enamel shrinking until it is squeezed out of existance

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10
Q

How does the Triangle shape at the distal end of the Ameloblast serete enamel matrix

A

Only at one side of the triangle

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11
Q

Before the Secretory phase, what happens to the Ameloblasts

A

The dissolve the basement membrane and form tight junctions

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12
Q

what happens during the maturation stage

A

The basemement membrane reforms and the Ameloblasts go through ruffled and smooth phases

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13
Q

Roll of the Ruffled Ameloblasts

A

Secrete proteases and acidify to remove the enamel matrix

also help with Calcium binding

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14
Q

Junction of Ruffled Ameloblasts

A

Tight distal junctions

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15
Q

Junction of Smooth Ameloblasts

A

Leaky distal Junctions

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16
Q

Roll of Smooth Ameloblasts

A

Allow the degraded proteins to diffuse and leave

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17
Q

what is the space between rod and interrod enamel

A

Sheath space

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18
Q

The triangular process of the Ameloblasts

A

Tomes Process

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19
Q

What are the faces of Tomes Process

A

Secretory and Nonsecretory faces

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20
Q

what are some steps ameloblasts seem to do in the maturation stage to remove acid

A

Stop, remove acid by having the tight junctions get leaky, and then continue

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21
Q

Why do Hunter Schreger bands form

A

Result of a section phenomenon through two enamel rod directions

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22
Q

How do rods travel to the surface

A

Rods bend, go up and over, annd then go up again

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23
Q

why do rods go in a curvey pattern

A

allows rods to pack tightly at the enamel surface where the enamel area is greater than the dej
-occlusal surface force dissipated cervically and laterally

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24
Q

where do rods locate due to hunter-schreger bands

A

Laterally and occlusally from its point of origin

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25
how do hunger schreger bands form around the cusp
Form in circular arrangements
26
How does Enamel formation start location wise around the tooth
At the cusp tip then proceeds cervically
27
what kind of enamel foes the Hunger-schreger bands form
Gnarled enamel
28
Cohorts of Ameloblasts sequentially form what type of enamel rods
Gnarled enamel rods
29
Junctions between the Cohorts are responsible for
Striae of Retzius
30
Perikymata are the surface extension of what
Lines of Retzius
31
what is the Neonatal line
An enlarged line of Retzius due to the stress of birth
32
Types of Ameloblasts
Pre-ameloblasts Secretory ameloblasts Maturation ameloblasts Reduced ameloblasts
33
Proteins secreted in the secretory stage
``` Structural enamel proteins (amelogenin, Ameloblastin, Enamelin) Enamel Proteinase (matrix Metalloproteinase-20) ```
34
Proteins secreted in the Maturation stage
Enamel Proteinase (kallikrein-4)
35
what is Amelogenesis Imperfect
GRoup designation for a variety of inherited conditions displaying enamel malformations in the absence of non-dental phenotypes
36
Result of Hypoplastic Amelogenesis Imperfect
Thin enamel
37
What is the Defect in Hypoplastic Amelogenesis Imperfecta
Secretory stage defects
38
Result of Hypopmaturation Amelogenesis IMperfect
Soft enamel
39
Results of Hypocalcified Amelogenesis IMperfecta
Soft and Thin enamel
40
What is the defect in Hypomaturation Amelogenesis IMperfecta
Maturation stage defects
41
what does an Amelogenin mutation result in
AI on the X chromosome
42
where is Ameloblastin gene located
On chromosome 4
43
where is Enamelin gene located
On chromosome 4
44
roll of Amelogenin
regulate crystallite spacing
45
where does Ameloblastin accumulate
In the sheath space
46
Where is Enamelin found
Intact enamelin is restricted to the mineralization front
47
What structural enamel prtein is no Glycosylated
Amelogenin
48
what makes up 90% of the structural enamel proteins
Amelogenin
49
what are the Enamel proteinases
``` Matrix Metalloproteinase (MMP20) Kallikrein-4 (KLK4) ```
50
when is MAtrix Metalloproteinase released
Secretory stage
51
roll of MAtrix Metalloproteinase
Processes enamel proteins
52
when is Kallikrein-4 released
Transition/maturation stages
53
what does KAllikrein-4 do
Degrades enamel matrix
54
what kind of Disease does Amelogenin mutations lead to
X linked Hypoplastic AI
55
what chromosomes are the human Amelogenin genes fround on
X and Y chromosomes
56
what happens if the Amelogenin genes are knocked out from protein sectretion
the DEJ(ameloblasts extensions in the predentin) looks the same as the wild-type but with no detectable protein secretion
57
what happens to the Collegen as a resultl of the Amelx gene being knocked out
Initial ribbons that would form on collagen mineral are short, less organized and elongate slowly apparent cystal fusions
58
what is the Amelx phenotype
Distrinctive vertical banding pattern on the enamel of affected heterozygous females due to random inactiviating the X chromsomes
59
what kind of disease does Ameloblastin (Ambn) mutation lead to
Autosomal recessive Hypoplastic AI
60
Phenotype of Ambn
Poorly formed Rods (prisms) | Shitty enamel
61
what does Enamelin (ENAM) mutation lead to
Autosomal Dominant Hypoplastic AI
62
what happens when Enam is eliminated
No enamel ribbons even after extensive dentin mineralization
63
what is the Phenotype if Heterozygous ENAM mutation
mild phenotype, with localized pitting defects and groove/shallow pits formed in paralel horizontal lines
64
what happens when Both ENAM allels are defective
No enamel layer
65
what does MAtrix Metalloproteinase-20 do
Secreted early in development of enamel to cleave strucutural proteins Amelogenin, enamelin, and ameloblastin
66
how much MAtrix Metalloproteinase-20 is present
Very small amounts
67
what do people with Enamel mutations often have
Severe carries
68
how does A westernblot lot when MMP-20 is removed
Will have one large protein left, but a lot of smaller bands will appears as cleaved products
69
what does mmp20 do the DEJ
Weak Dentin-Enamel JUnction
70
what does MMP20 mutation lead to
Hypoplastic/hypomaturation AI
71
Phenotype of MMP20 mutation
Pigmented hypopmaturation AI normal size teeth, but enamel does not contrast well with dentin on radiographs enamel tends to chip
72
presence of Strcutural enamel proteins and MMP20 in species with no teeth
No, since there is no selective pressure to maintain these genes
73
what happens when matuaration stage enamel proteins are mutated
AI
74
Proteins of MAturation stage
Kallikrein 4 (KLK4) WD repeat protein 72 (WDR72) Chromosome 4 open reading frame 26 (C4orf26) Solute Carrier Family 24, member 4 (SLC24A4)
75
Roll of Kallikrein 4
Serine protease
76
Mutation in Kallikrein 4 leads to
Autosomal-recessive AI
77
roll of WD repeat protein 71
Intracellular protein
78
mutation of WD repeat protein 72 cuases
Autosomal recessive AI
79
roll of Chromosome 4 open reading fram 26
secreted to hlep enamel mature
80
roll of Solute carrier family 24, member 4
Proton pump that may rid enamel of protons
81
when is Kallikrein-4 expressed
During mid-late stage enamel develop when enamel has reached its full thickness and when proteins are actively removed rom the hardening matrix
82
roll of Kallikrein-4
degrades proteins to facilitate their removal from the enamel matrix
83
effect of REmoving Kallikrein-4
Enamel has normal thickness and rod and interrod org | However; enamel crystals do not grow together
84
what does A kallikrein-4 mutation lead
Autosomal Recessive Hypomaturation AI
85
phenotype of KLK4 mutation
``` ARAI normal sized teeth yellow brown Enamel is slightly opace Fracturing enamel ```
86
when is Family with Sequence similarity 83 member H
uniquitously expressed
87
what does Family with sequence Similarity 83 affect
dental enamel
88
what does Mutation in Family with sequence similarity 83 member H lead to
Autosomal dominant hypocalcified amelogenesis imperfecta
89
what is most common form of AI in the US
fam83H mutations for autosomal dominant hypocalcified amelogenesis imperfecta
90
FAM20A mutations lead to
``` Enamel hypoplasia Gingival hypertrophy Kidney calicifcations Enamel Renal syndrome Delayed eruption Pulp calcifications ```
91
FAM20A mutations lead to
``` Hypoplastic amelogeneis imperfecta Gingival hyperplasia kidney calcifaction intrapupal calcification delayed tooth eruption failure for tooth development ```

oral histology (14 decks)

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