Test 2 Flashcards
1
Q
How is PKU Acquired?
A
Autosomal recessive.
2
Q
How is hemophilia A inherited?
A
X-linked recessive.
3
Q
How is huntingtons disease acquired?
A
Autosomal dominant.
4
Q
How is fragile-X syndrome inherited?
A
X-linked recessive.
5
Q
How is marfans syndrome acquired?
A
autosomal dominant.
6
Q
What is the mode of inheritance of Osteogensis imperfecta?
A
Autosomal dominant.
7
Q
What is the mode of inheritance of Albinism?
A
Autosomal recessive.
8
Q
Male pattern-baldness is inherited how and is AKA?
A
X-lined recessive and is aka androgenic alopecia.
9
Q
How is Osteogenesis imperfecta acquired?
A
Autosomal dominant.
10
Q
How is albinism aka hypomelanism acquried?
A
Autosomal recessive.
11
Q
How is Duchene-type muscular dystrophy inherited?
A
X-linked recessive.
12
Q
How is Neurofibromatosis type I acquired?
A
Autosomal dominant.
13
Q
What is the mode of inheritance of familial hypercholesterolemia?
A
Co-dominant.
14
Q
How is achondroplasia acquired and what are the characteristics?
A
Autosomal dominant. And non-proportional dwarfism.
15
Q
How is tay-sachs disease acquired?
A
Autosomal recessive.
16
Q
How is PKD aquired?
A
Autosomal dominant.
17
Q
How is hemochromatosis inherited and it is aka?
A
Autosomal recessive and is aka hereditary hemochromatosis.
18
Q
How is Common colorblindness inherited?
A
X-linked recessive.
19
Q
How is Cystic Fibrosis inherited?
A
Autosomal recessive.
20
Q
Will more conditions be autosomal recessive or dominant inheritance?
A
Autosomal dominant.
21
Q
What genotype of people will be affected, unaffected and carriers for autosomal dominant?
A
AA- Affected. Aa- Affected. Aa- unaffected. No carriers.
22
Q
What will the genotype be for most people with an autosomal dominant genetic condition?
A
Heterozygous. Aa.
23
Q
Huntingtons disease is characterized by what?
A
Progressive involuntary twitching, personality change and dementia and death.
24
Q
What is the typical age of onset for Huntingtons disease?
A
40 years.
25
Osteogenesis imperfecta affects what?
It is a connective tissue disorder of TYPE I COLLAGEN.
26
What are the symptoms of Osteogenesis imperfecta?
Brittle bone disease, includes short stature, malformed bones, loose joints, blue sclera, opalescent teeth, hearing deficit.
27
What is the most common form of osteogenesis imperfecta?
Type I.
28
What is another name for Von Recklinghausen disease?
Neurofibromatosis type I.
29
How is neurofibromatosis type I characterized?
Multiple neurofibromas.
30
How will most people get achondroplasia aka achondroplastic dwarfism?
75% from new mutations and might be as high as 90% from new mutations.
31
What are the characteristics of marfans syndrome?
Tall persons with dis-proportionally long limbs, arachnodactyly, sublucation of the eye lense, and cardiovascular defects.
32
What are the characteristics of Polysystic Kidney disease AKA PKD?
Multiple cysts in the kidneys.
33
What genotype of people will be affected, unaffected and carriers for autosomal recessive?
AA- unaffected. Aa- Unaffected (carrier). Aa- Affected.
34
Who are the people that are carriers of autosomal recessive traits?
We are all carriers of 5-8 recessive genes. This is our genetic load.
35
How would autosomal recessive genes be typically transmited?
AA x Aa= passing on the recessive gene 50% of the time.
36
With autosomal recessive diseases when the condition appears in a sibship what is the risk of another sibling getting the disease?
25%.
37
PKU is what type of disorder?
Amino acid metabolism.
38
How common is PKU?
Uncommon.
39
What are the clinical features of PKU?
Severe mental retardation, hypo-pigmentation, an unusal odor.
40
Albinism is what type of disorder?
Amino acid metabolism.
41
How common is albinism?
Uncommon.
42
What is another name for GM2 gangliosidosis?
Tay-Sachs disease.
43
Tay-sachs disease is what type of disorder?
Lipid metabolism.
44
How common is Tay-sachs disease?
Uncommon in general population, but common in ashkenazi jewish population.
45
What is another name for cystic fibrosis?
Mucoviscidosis.
46
Cystic fibrosis aka mucoviscidosis is a disorder of what?
Chloride transport.
47
Cystic fibrosis aka mucoviscidosis is a chloride transport disorder that results in what?
Exocrine gland secretion difficulties that leads to very salty sweat, thick mucus secretion---> bacterial growth.
48
Accumulation of mucus seen with cystic fibrosis results in what?
Blockage of the biliary tract and poor digestion and pancreatic insufficiency.
49
How common is Cystic fibrosis?
Not uncommon.
50
What would clinical features of Cystic fibrosis be?
Respiratory infections.
51
What is the name for a disorder that is only semi-dominant or semi-recessive?
Co-dominant or intermediate inheritance.
52
Will McKusicks mendelian inheritance in man recognize co-dominant inheritance?
No.
53
What would the phenotype be for a co-dominant inheritance for AA, Aa, aa?
AA- unaffected. Aa- semi-affected. Aa- affected.
54
What is another name for familial hypercholesterolemia?
Hyperlipoproteinemia type Iia.
55
Familial hypercholesterolemia is an autosomal co-dominant disorder of what?
High serum cholesterol, High LDL.
56
Familial hypercholesterolemia is a ____ disease.
LDL receptor
57
What are the different forms of familial hypercholesterolemia?
Mild and severe.
58
How common is the mild case of familial hypercholesterolemia?
Possibily as common as 1 in 500.
59
Mild cases of familial hypercholesterolemia have what type of genotype?
Aa. Heterozygous.
60
What will cholesterol levels be like for heterozygous familail hypercholesterolemia people?
Total serum cholseterol in the 250-500 mg/dl range.
61
What are the MI risks of mild cases of familial hypercholesterolemia people?
Elevated, by age 60 seen in 85% of males and 50% of females.
62
What is the severe form of familial hypercholesterolemia like?
Vary rare.
63
Sickle cell anemia results in formation of sickling cells that occlude microvasculature causing what?
Vaso-occlusive crises, Anemia.
64
What is the genotype of a classic sickle cell anemia patient?
homozygous.
65
What will heterozygot sickle cell anemia people like?
Essentially normal, but have a sickle cell trait if placed in a low oxygen environment.
66
Who will sickle cell anemia be more common amoung?
People of African and or mediterranean descent. 1 in 12 African Americans has the sickle cell trait.
67
What is the evolutionary advantage of being heterozygote for sickle cell anemia? What is this called?
Carriers are somewhat resistant to malaria infection called Heterozygote superiority.
68
A young female with achrondroplastic dwarfism intends to have children. Her husband is normal and there is no history of the disorder in his family. What would be the approzimate risk of this woman having a child with the same disease ?
50%.
69
A 20 year old male has a father that has just been diagnosed with Huntington's disease. Setting aside the issue of a DNA test for the HD gene, what is the chance that he (this son) might get Huntington's disease like his father? At this point what would be the probability of this son having a child with the disorder?
50%, 25%.
70
Imagine that you and your mate both suffer from a rare autosomal dominant condition. However, it is known that the homzygous dominant state is considered a lethal genotype (resulting in spontaneous abortion in the first trimester of pregnancy). What is the probability of you and your mate producing a normal child from those that are live-born?
1/3 of them.
71
A couple tells you that they have a daughter being treated for phenylketonuria what is the probability of this couple having a second child with PKU?
25%.
72
An albino male mates with a normally pigmented female; the female has an albino mother. What would be the probability of this couple having an albino child?
near 50%.
73
A couple report that they have a son with type I neurofibromatosis. Both parents are normal and there is absolutely no history of this disorder in their families. What would be the approximate chance of this couple having another child with the disease (aka von recklinghaused disease)?
Near 0%.
74
A male with alcaptonuria (autosomal recessive) mates with a typical female in the population. What is the probability of this couple having a child with alcaptonuria?
Near 0%.
75
A male with alcaptonuria (autosomal recessive) mates with a typical female in the population. What is the probability of this couple having a child with alcaptonuria? Second part what if the incidence of alcapotnuria carriers was 1 in 150 in the population?
1/2 X 1/150= 1/300
76
You are normal but your brother died of Tay-sachs disease at age 2. What is the probability that you are a carrier for Tay-sachs?
2/3.
77
What is the normal Karyotype of a female and a male?
Female- 46,XX. Males- 46,XY.
78
What part of DNA is the sex-determining region?
SRY on the Y chromosome.
79
The Vast bulk of genes for secual differences are found on what chromosome(s)?
Autosomal.
80
Will males of females be heterogametic or homogametic and why?
Females- homogametic sex they can only give an x. Males- Heterogametic sec because they can give an X and a Y.
81
What is the theoretical production rate of males to females?
50:50 male:female.
82
What is sex chromatin?
Prior to karyotypes it was possible to view interphase nuclei of some cells and determine gender by looking for so called sex chromatin. It may appear as a lump of heterochromatin.
83
What is a Barr body?
A lump of nuclear chormatin which is when an X chromosome shuts down at random in females since they have 2 X chromosomes.
84
Generally the greater the number of sex chromosomes the more likely there will be what?
serious phenotypic consequences.
85
What is Klinefelter's syndrome aka?
Testicular hyalinization.
86
What is the karyotype for klinefelter's syndrome?
47,XXY.
87
Klinefelter's syndrome affects who?
Males.
88
What will Klinefelter's syndrome cause?
Sterility.
89
What are the characterisitics of someone with Klinefelter's syndrome?
Tall/Lanky, Gynecomastia.
90
How common is Klinefelter's syndrome?
Not uncommon.
91
Turner's syndrome is aka?
Gonadal dysgenesis.
92
What is the karyotype for Turners syndrome?
45,X0.
93
Who can be affected by Turner's syndrome?
Females.
94
What are the clincial features of Turner's syndrome?
Sterility, Broad/"Shield" chest, webbed neck.
95
How common is Turner's syndrome?
Somewhat uncommon.
96
Turner's syndrome makes up about 10% of what?
all spontaneous abortions.
97
What is the name for people called intersex?
Hermaphroditism.
98
Sex chromosome abnormalities as a group are _______.
Relatively common.
99
Genes found on the Y chromasome are called what?
Holandric.
100
Genes found on the X chromasome are called what?
X-link.
101
What will the phenotype be like for X-linked recessive inheritance for Females- AA, Aa, aa, and Males- AY, aY?
Females: AA- unaffected, Aa- unaffected carrier, aa- affected. Males: AY- unaffected, aY- affected.
102
With X-linked recessive inheritance the vast majority of affected persons are what?
Males.
103
An affected male (X-linked recessive) can not pass the trait to who?
His son or to further generations through his son.
104
Hemophilia A is a condition due to what?
Missing of blood clotting factor VIII.
105
What will hemophilia A cause and how common is it?
Bleeding and this disease is very uncommon.
106
How common is colorblindness?
Very common.
107
What will colorblindness cause?
a "red-green confusion".
108
How common is Duchene-type muscular dystrophy?
uncommon.
109
What is the the most common cause of inheritable mental impairment?
Fragile-X syndrome.
110
What are the triplicate expansion mutations like for fraigile-X syndrome?
The have a variable expansion that produces variable expressions.
111
How common is Fragile-X syndrome?
Not uncommon.
112
How common is male pattern-baldness?
Very common.
113
What is sex-influenced inheritance?
Some genes are expressed differently depending upon the sex of the individual.
114
What are the symptoms of hemochromatosis aka hereditary hemochromatosis?
malaise, liver cirrhosis, bronzing of the skin, cardiomyopathy.
115
How common is hemochromatosis aka hereditary hemochromatosis?
common.
116
How can hemochromatosis aka hereditary hemochromatosis be prevented?
Periodic phlebotomies comparable in volume to a routine blood donation.
117
Will males or females mainly get hereditary hemochormatosis aka hemochromatosis and why?
Males because it is prevented in females by monthly menstrual cycle.
118
What is Sex-limited inheritance?
Involves the expression of genetic trait that is limited to one sex or another.
119
How many chromosomes would a person with the common form of Klinfelter's syndrome have?
47 of them.
120
How many chromosomes would a person with the common form of Turner's syndrome have?
45 of them.
121
A couple reprots that they have a child with Lesch-Nyhan syndrome (which you look up in MIM and find is X-linked recessive). What is the sex of the child? What is the chance of this couple producing a second child with the disease?
male. 1/4.
122
A female is known to carry a very rare, deadly, X-linked recessive condition (which causes spontaneous abortions when expressed in a fetus). What proportion of her offspring would be expected to be males?
1/3 of them.
123
How many barr bodies would an XXXY individual have? How many Barr bodies would a XXXX individual have?
2 and 3.
124
A male with hemophilia is being effectively treated ( and is reproductively normal). If he should mate at random in the population, what would be the probability of him having an affected child? In this case assume carrier females are 1 in 5,000.
If he marries a carrier the chance is 1/2 and multiply that by the chance of marring a carrier 1/5000 so answer is 1/10,000.
125
A male with common colorblindness mates with a woman with normal color vision but whose father had the same form of common colorblindness (e.g., basic, red-green confusion). What is the probability of this couple producing an affected daughter?
1/4 of them.
126
What is the genotype pattern found with a double heterozygous cross?
1:2:1:2:4:2:1:2:1.
127
What is the phenotype pattern found with a double heterozygous cross?
9:3:3:1
128
The probability approach to determining genotype and phenotype requires what?
The disorders are independent of each other.
129
What are the possible genotypes of AaCc X AaCc (use probability approach)?
AA=25%, Aa=50%. .aa- 25%. CC=25, Cc=50%, cc- 25%. Then multiply the % togther to see the probability of getting any combination.
130
What are 2 situations tha tcan foul up the probability method?
Linkage, Epistasis.
131
What is Likage?
Where 2 genes are on the same chromosomes.
132
What is Epistasis?
Where 2 genes interact in some metabolic/biochemical way.
133
A male/female couple are both known to be carriers for both Tay-sachs disease and albinism. What is the probability of this couple producing a phenotypically normal child with respect to these two disease?
probability is 9/16.
134
A man with both Marfan syndrome and common colorblindness mates with a phenotypically normal woman: their first child is a colorblind boy who is otherwise normal. What is the probability of their second child being just like the father (i.e., being a male with both marfan syndrome and common colorblindess)?
Probability is 1/8
135
A male/femal couple both have brachydactyly (an autosomal dominant condition that is lethal in the homozygous dominant state); their first born child has phenylketonuria (so these parents must be carriers for PKU). What is the probability of this couple giving birth to a phenotypically normal child?
Probability of normal child is 1/4.
136
A male with classic hemophila (type A) has an albino mother. A female has a hemophiliac son by another mating , and also has an albino mother. If these 2 described individuals mate, what would be the probability of giving birth to a female with both conditions?
probability of a female with both conditions is 1/16.
137
Imagine the following mating involving 4 independent, autosomal recessive traits: AaBbCcDd X AaBbCCDD. What would the probability of producing offspring with genotype of aaBBCcDd?
probability is 1/64.
138
When will crossing over take palce?
Prophase I.
139
What is it called when 2 genes will recombine in different ways?
Recomibinant types.
140
What is incomplete linkage?
2 genes are relatively near each other they will remain relatively linked, but some recombinant offspring types will be seen.
141
What is likage mapping?
See which genes or diseases are often seen together and this can help map out where on chromosomes genes are located.
142
The genes for ataxia telangiectasia (autosomal recessive) and classic albinism are known to very close to each other at about 11q14-q23 (assume side by side). Imagine that a male is known to be heterozygous for both of these 2 disorders. Furthermore, let us imagine that this male reports that ataxia telangiectasia is known to be in the lineage on his mothers side of the family, and that albinism runs in his fathers side of the family. Assuming no crossing over, what would be the probability of this male producing gmaetes containing BOTH of the recessive alleles for the two diseases in question?
near 0%.
143
What is the cellular basis for recombination of linked genes?
Crossover.
