Genetic Disorders-Bickmen Flashcards
(74 cards)
1
Q
Somatic cells
A
contain 46 chromosomes
23 pairs
diploid
2
Q
Gametes
A
contain 23 chromosomes
haploid
one member of each chromosome pair
3
Q
Meiosis
A
formation of hapliod celld from diplios cells
4
Q
Autosomes
A
the first 22 of the 23 pairs of chromosomes
the two members of each pair are idetical (homologus)
5
Q
sex chromosomes
A
remaining pair of chromosomes
6
Q
karyotype
A
ordered display of chromosome
(Picture )
7
Q
chromosomes mutations def
A
any inheritied alteration of genetic material
8
Q
types of mutations
A
base pair subsitiution
frame shift mutation
9
Q
base pair mutation
A
one base pair is substituted for another
- silent
- missense
- nonsense
10
Q
frame shift mutation
A
insertion or deletion of one or more base pairs
causes a change in the readin frame
11
Q
Non-mutation chromosomal alterations
A
- Polymorphisms
- Epigenetic changes
- Alterations in non-coding RNAs
- Translocation (leukemia, philly chomosome)
12
Q
polymorphisms
A
Non-mutation alteration
- abnormal number of copeis of one or more sections of DNA
- single nucleotide polymorphisms (SNP)
13
Q
what is the difference between an SNP and point mutation
A
point mutation occurs in less than 1% of the population
SNP occurs in more that 1% of the population- common varation in single mucletotide
14
Q
epigenetics
A
non muation alteration
non DNA changes
alterations in gene or protein expression
environmental
15
Q
alterations in Non-coding RNAs
A
non-mutatoin alteration
regulating genes that do not code for proteins
16
Q
translocation
A
- non mutation alteration
- interchanging of material between non homologous chromosomes
- when two chomosomes beak and the segments are rejoined in an abnormal arrangement
17
Q
Euploid Cells
A
- Has the normal number of chromosomes
- Different for hapliod vs. diploid
18
Q
Polyploid cell
A
cell has a multiple of 23
19
Q
examples of polyploid
A
- Triploidy: three copies of each chromosome (69= 3x23)
- Tetraploidy: four copies of each chromosome (92=4x23)
both are embryonic lethal (10% of miscarriges)
20
Q
Aneuploidy
A
a somatic cell that does not contain a multiople of 23 chromosomes
21
Q
types of aneuploidy
A
- trisomy: 3 copies of one chromosome is thrisomic
- monosomy: 1 copy of any chromosome in monosomic
monosomy is usually lethal
22
Q
A
23
Q
better to have …
A
too many than too few chromosomes
24
Q
disjunction
A
normal separation of chromosomes during cell division
25
Nondisjunction
* usally in aneuploidy
* failure of the homologous chromosomes or sister chromatids to separate in meiosis or mitosis
26
chromosome aberrations
1. Nondisjunction
2. aneuploidy
3. polyploid
27
If a human fetus has 45 chromosomes in it's cell it would be called a\_\_\_ and would be a result of \_\_\_\_\_
Aneuploidy
Monosomy
28
Types of autosomal aneuploidy
1. Trisomy 13, 18, 21
2.
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Trisomy 13
Autosomal Aneuploidy
**_Patau Syndrome_**
* Polydactyly
* Mental retardation
* microcephaly
* usually leathal early in life due to heart deformities
* **Dental Features: celft lip and palate**
30
Trisomy 18
Autosomal Aneuploidy
**_Edwards Syndrome_**
* Kidney malformation
* *protruding intestines*
* mental retardation
* small size
* Usually leathal early on due to heart defects
* **Dental features: Micrognathia**
31
Trisomy 21
Autosomal Aneuploidy
**_Down Syndrome_**
1. Risk increases with parental age
2. Maxillary retrognathia (depressed mand)
3. enamel hypoplasia
4. irregular placement of teeth
5. severe periodontal disease
6. delayed eruption
32
Trisomy X
Sex chromosome Aneuploidy
* Lyonization: little physical manifestation
* variable symptoms: sterility, menstrual irregularity, mental retardation
* symptoms worsen with each additional X
XXX→ usually no symtoms, only one X is active
33
Turner Syndrome
Sex Chromosome Aneupliody
* Only **_one X_** chromosome →XO Female
* underdeveloped ovaries (removed bc they are cancerous)
* Short
* webbing of the neck
* Edema
* shield chest
* out-turned arms
* low hairline at back of the neck
34
Klinefelter Syndrome
Sex chromosome aneuploidy
* At least **_two X_** and **_one Y_** chomosome →XXY
* abnormalities increase with each X → XXXY, XXXXY
* Male appearance
* can be fertile
* at puberity, breast and hip development
* underdeveloped male genitals
* long limbs
35
Klinefelter syndrome
dental feature
**_Taurodontism_**-conditon of molars wherein the body of the tooth and pulp chamber is enlarged vertically at the expense of the roots
36
Which of the following is an example of trisomy? Is it sex chromosome or autosomal ?
## Footnote
A. Fragile X
B. Turner Syndrome
C. Klinefelter Syndrome
D. Cri du chat Syndrome
klinefelter
Sex chromosome
37
Normal, Genetics
Does not have a disease gene and not a carrier, phenotypically normal
Recessive Disease= AA
Dominant Disease= aa
38
Carrier
Has disease gene and is phenotypically normal, not affected by it
Recessive disease=Aa
39
Affected
Has a disease gene and is phenotypically affected
Recessive Disease= aa
Dominant Disease= Aa/ AA
40
For a person to demonstrate a recessive disease the
pair of recessive genes must be inherited
41
Genetic Pedigrees
used to study specific geneitic disorders within families
(female=circle and male=square)
42
Risk of occurance
the prob of having a child with a genetic disease
43
Autosomal Dominant
* abnormal allele is Dominant
* normal allel is recessive
* two sexes exhibit the trait in equal proportions
* no generation skipping
**Normal and Affected**
44
Autosomal Recessive
* Abnormal allele is recessive
* homozygous for abnormal trait to express disease
* Affects genders equally
* May skip generations
**Carrier, Normal, and Affected**
45
Sex-linked Dominant
Abnormal allele is Dominant
sex matters
normal and affected
46
Sex linked recessive
abnormal allele is recessive
sex matters
carrier, normal, affected
47
Achondroplasia
most common form of dwarfism
autosomal disorder
48
Marfan Syndrome
Autosomal Dominant Disorder
* Abnormality of fibrillin 1 (elastic fibers)
* Disorder of connective tissue
* tall with long extremities
* bilateral subluxation of the eye lens (ectopica lentis)
* Cardiovascular Lesions: mitral valve prolapse
* **Dental: increased risk of caries and cleft palate**
49
Ehlers-Danlos Syndrome
Autosomal Dominant
defects in collagen
* skin and joint hypermobility
* easy bruising
* Gorlin's Sign
50
Treacher Collins Syndrome
Autosomal Dominant
abnormal dev. of 1st and 2nd branchial araches
* underdeveloped mandible
* downward slanting palpebral fissures
* Deformed ears
* possible cleft palate
51
Penetrance
% of individuals with a specific genotype who also ecpress the expected phenotype
52
Incomplete penetrance
Autosomal
Individual who has the gene for a disease but does not express the disease
53
example of incomplete penetrance
Retinoblastoma (eye tumor in children)
demonstrates incomplete penetrance (90%)
54
Expressivity
variation in a phenotype associated with a cetain genotype
55
Examples of Expressivity
Autosomal Dominant
**Neurofibromatosis** (von Recklinghausen disease)
* varies from dark spots on the skin to malignant neurofibromas, scoliosis, gliomas, neuromas, etc.
56
Autosomal recessive disorder occurence risk
when two parents are carriers of an autosomal recessive disease
(risk 25%)
57
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Autosomal recessive Disorder genotypes
normal: DD
Carrier: Dd
affect: dd
59
increase risk of autosomal recessive disorder
consanguinity (insest)
60
Autosomal recessive disorders storage diseases
Lysosomal
Glycogen
61
Lysosomal Storage Diseases
Autosomal Recessive
1. Gaucher's
2. Tay-Sachs
3. Niemann-Pick
deficiency of a particular lysosomal enzyme or protein resulting in an accumulation of a metabolite
62
Gaucher's disease
Deficient enzyme:
Accumulating Metabolite:
Cell Affected:
Austosomal Recessive- Storage Diseases
* Deficient enzyme: Glucocerebrosidase
* Accumulating Metabolite: Glucocerebroside
* Cell Affected: Macropage
Enlarged macrophage in the spleen
63
Tay-sachs
Deficient enzyme:
Accumulating Metabolite:
Cell Affected:
Autosomal Recessive- storage diseases
1. Deficient Enzyme: Hexosaminidase A
2. Accumulating Metabolite: G Ganglioside
3. Cells affected: Neurons
leads to motor and mental deficits, blindness, dementia
**enlarged pale neurons**
64
Niemann-Pick disease
Autosomal Recessive lysosomal storage disease
* Deficient enzyme: Sphingomyelinase
* Accumulating Metabolite: Sphingomyelin
* Cell Affected: Neurons and phagocytes
**Kupffer cells have foamy appearance**
65
Storage Disease-Glycogen
autosomal recessive disorder
1. von Gierke's disease (type I)
2. Pompe's disease (type II)
3. Cori's disease (type III)
4. Brancher Glycogenosis (type IV)
5. McArdle's syndrome (type V)
alteration in enzymes responsible for glycogen metabolism
66
von Gierke's
Autosomal Recessive Glycogen storage
**Type I**
**deficient enzyme: Glucose 6-phosphatase**
**Tissue affected: Liver and kidney**
foamy hepatacytes
67
Pompe's disease
autosomal recessive storage glycogen
**Type II**
**Deficient Enzyme: Lysosomal glucosidase**
**Tissue affected: Heat**
Large vacuales in cardiomyocytes
68
Cori's disease
Autosomal recessive glycogen storage disease
## Footnote
**Type III**
**Deficient enzyme: debranching enzyme**
**Tissue affected: Heart, liver, skeletal muscle**
**enlarged hepatocytes**
69
Brancher Glycogenosis
Autosomal Recessive glycogen storage disease
## Footnote
**Type IV**
**Deficient Enzyme: Branching Enzyme**
**Tissue affected: Heart, liver, skeletal muscle, brain**
**enlarged hepatocytes**
70
McArdle's Syndrome
Autosomal recessive glycogen storage disorder
Type V
Deficient Enzyme: Muscle phosphorylase
Tissue Affected: Skeletal Muscle
Large vacuales in myocytes
71
Chediak-Higashi Syndrome
Autosomal recessive Disorder
mutation of lysosomal trafficking regulator gene (LYST)
* **Partial albinism**
* **Photophobia**
* **Compromised immunity**
* **neuropathy**
**Fusion of lysosomal granules**
72
X-linked disorders
* Recessive
* affected males cannot transmit the genes to sons but will to ALL daughters
* sons of female carriers have a 50% risk of being affected
73
Sex-linked disorders examples
Hemophilia A
Hemophilia B
Duchenne Muscle Dystrophy
color blindess
74
what would be the occurrence risk for color blindness in the daughter of a female carrier and a normal father?
0%
