gen path exam2

Question 1

when only one pair of autosomal chromosomes is impacted by a disorder.. this is a homo/hetero (choose one) -zygous disorder?

Answer 1

when only one of the 2 autosomal chromosomes is impcted by a genetic disorder, the individual has a HETEROZYGOUS disorder

if both chromosomes of the gene loci are affected, the individual is homozygous for the disorder

Question 2

approximately how many protein endcoding genes does the human genome contain?
100, 1000, 10000, 20000, 50000, 100,000?

Answer 2

The human genome contains about 20k protein-encoding gene sequences.

Question 3

fragile X syndrome is an example of what type of mutation?

Answer 3

Fragile X syndrome is an example of a trinucleotide repeat mutation where there is an amplification of sequence of 3 nucleotides

Question 4

what is the role of microRNAs?

Answer 4

microRNAs inhibit the translation (gene code into mRNA) of their targer mRNA into their correspodning prtns.. micro RNAs function is an example of alterations in protein coding genes that is NOT a mutation

Question 5

what are epigenetic changes?

Answer 5

epigenetic changes are modulation of gene expression without altered DNA sequence. for exampl,e methylation of a gene sequence reduces protein sntehtisis,, a function in homeostasis, etc.

Question 6

Mendelian Disorders are Diseases caused by single gene defects.
T/F?

Answer 6

mendelian disorders are diseases caused by single-gene defects. there are autosomal dominant, autosomal recessive, and x-linked mendelain disorders.

Question 7

Mendelian single-gene disorders:: pair the type with the transmission pattern correctly:

autosomal dominant:: expressed if only one gene loci is affected

autosomal recessive:: transmitted by sex chromosomes

x-linked: expressed of both gene loci are affected with the disorder

Answer 7

correct pairings for Mendelian single gene disorders are as follows::

autosomal Dominant :: expressed if only one gene loci is affected

autosomal recessive:: expressed only if BOTH gene loci are affected (( or, rarely, unfavorable lyonization process that eliminates healthy X chromosome copies)

X-linked: transmitted via Sex-chromosomes. Females are usually the carriers since they have a 2nd X chromosome to provide normal function while males with only the defective X gene express the disorder. Unfavorable lyonization can expressed X-linked disorder in females as well

Question 8

When are the majority of autosomal Dominant disoders exhibited? (early/delayed onset?

Answer 8

AD disorders usually have a delayed age of onset even though the defective gene is present at birth. AD disorders often present with physical changes..

Question 9

If only one parent has the defective gene for an Autosomal dominant gene./. what are the chances the offspring with express the disease?

Answer 9

about half of the ofspring will have an AD disease if only one parent is affected

Question 10

what type of mendelian disorder is the most common?

Answer 10

Autsomoal recessive disorders are the most common type of Mendelian (single gene defect) disorder.
25% of offspring of heterztgous parent carriers get the disease.

Question 11

what sort of mendial disorder is described by the following:

• early age onset
• often complete penetrance (100% phenotypic expression)
• many of this type disorder impacts errors in metabolism
• heterozygous individuals do not often display the condition clinically but do have lower levels of normal enzymes

Answer 11

Autosomal recessive disorders are described.

Question 12

T/F There are just as many Y-linked disorders as known X-linked disorders

Answer 12

False. X-linked disorders exists while no Y0linked disroders are known. perhaps, only hairy ears are linked to Y-linked transmission

Question 13

the following hcaraceristics describe what sort of genetic disorder?/:

-mutant genes are on the X chromosome (sex chromosome)
-women must inhereit 2 mutated copies to be affected
-all men who inhereit the mutation are affected
-most are recessive disroders
0heterozygous females are carriers
-homozygous females and heterozygous males are affected

Answer 13

the previous decribes the transmission and disorder pattern for X-linked (sex-linked) disorders

men only receive on X chromosome from the mother, so if there is a mutation they automatically express the disorder since no normal copy exists. Vs. women who have 2 X chromosomes and therefore only affeted if 2 mutated X chromosomes are inherited.

• note, X-linked dominant disorders impact heterozygous, homozygous and hemizyougs individuals (all)

Question 14

What is lyonization?

Answer 14

Lyonization is the provess where all but one X chromosome is inactivated in the zygote. wither the maternal or paternal X may be inactivated in each cvell.. unfavorable lyonization is where thereis inactivation of more normal X chromosomes leading to clinical evidenvce of the disease in a heterozygous female.

Question 15

what disorder is an autosomal dominant disorder that results in abnormal fibrillin?

Answer 15

Marfan syndrome is an AD disroder of connective tissue resulting in abnormal fibeillin. due to mutation of FBN1 gene. prevalnce = 1:5,000.
-indiv. arachnodactyly- long limbs, spidery fingers.. prone to aortic aneurysm

Question 16

the following describes what condition?

• hyperextensible skin, hypermobile joints
• more than 6 different types of the syndrome
• freagile skin
• long wound healing
• hernia

Answer 16

The previous describes EhlerDanlos syndorme. which caused by mutation of structural protein .. here, a probelm with collagen syntehsis.

Question 17

what does primary hemostasis involve?

- what about secondary hemostasis

Answer 17

• primary hemostasis is via a temporary platelet plug

- secondary hemostasis follows, is fibrin CLOT formation via Activation of the coagulation cascade

Question 18

T/F

adhesion. and aggregation of platelets in response to vascular injury is described as secondary hemostasis

Answer 18

False. adhesion and aggregtion of platelets in response to vas. injury is described as PrIMARY HEMOSTASIS.
secondary hemostasis is a more permanent clot of Fibrin.

Question 19

what is von Willebrand factor?

Answer 19

Von Willebrand factor is an adhesion PROTEIN that connects platelets to injurt.

specifically, VWbF binds to the GP1b (glycoprotein 1b, the platelet surface membrane receptor) to the injury surface - bleeding occurs due to vascular injury which exposes subendothelial tissues = collagen (COLLAGEN exposed) that binds to VwbF

Question 20

what are the 3 main components necessary to achieve hemostasis?

Answer 20

to maintain hemostasis*, the 3 major compoents are the vascular walls, platelets, and coagulation prtns.

hemostasis is the ability to keep blood fluid while preventing blood loss from vascular damage

Question 21

what factor facilitates cross-linking of activated fibrin when making a clot?

Answer 21

Factor XIIIa (13a) cross-links fibrin molecules ti firm a fibrin clot (secondary hemostasis)

Question 22

what are the 2 pathways described in the coagulation cascade?

• is there pathway overlap?
• which pathway is more often indicated in bleeding disorders

Answer 22

there is the intrinisic and extrinsic coagulation cascade pathway.
- the pathways are a series of actiation cascase.. they meet at factor X and result in fibrinogen to fibrin activation and hence coagulation.
-the extrinsic pathway is more relevant to bleeding disorders (extrinsic cascade starts with activation of factor 7)
-

Question 23

how does activated Prtn C and S inhibit hypercoagulation?

Answer 23

APC activated prtn C, and S bind up activated coag cascade factors (factors 9,10,11,12a) so that these factors do not activate fibrin. with less coag factors avail, there is less coagulation as a result.

Question 24

what is a Factor V Leiden mutation?

Answer 24

A Factor V Leiden mutation promotes coagulation. Factor V muation gives coag factors (enzymes) resistance to deactivation via PrtnC/S

Question 25

What element is especially importnat to coagulation cascade activation?

Answer 25

Calcium Ca2+ is necessary for coag cascade activation

Question 26

what is another word for serine protease inhibitors?

Answer 26

Antithrombin is another word for serine protease inhibitors - SERPIN. antithrombin prevents activation of thrombin = less coag

Question 27

what are 3 ways coagulation in secondary hemostasis is regulated (( regulated meaning inhibited so balanced response)).

Answer 27

3 methods of balancing/ regulating coagulation/ hemostasis is via:

1) serine protease inhibitors (SERPINS) which bind up the thrombin activating cleavage enzy. serine protease
2) PRtnC/S complex which binds up free cofactors preventing them from activating the factors of the coagulation cascade
3) fibroltic system - via plasmin that degrades clots

Question 28

PT and PTT are lab tests used to test a px’s secondary hemostasis reaction::
please match the characteristic with the according test:
pathway : factos involved: time to clot:
extrinsic/ intrinsive
factors 5,7,10 fibrinogen -or- factors 5, 8,9,10,11,12
11-13 seconds -or- 28-35 seconds

Prothrombin Time:
Paritail Prothrombin time:

Answer 28

PT and PTT - tests screening hemostasis in indiv:
Prothrombin time:PT
measures time to clot in EXTRINSIC pathway nvolving factors 5, 7,2,10. The clot here forms faster than in intrinsic pathwya. extrinsic pthwy clot forms in 11-13 seconds. extrinsic pthway more implicated in bleeding disorders

Partial prothrombin time:PTT measures time to clot in Intrinsic pathway involving factros 5, 8-12/ intrinsic pathway clot forms in 28-35 seconds.

Question 29

what lab findings may be indicative disorders of primary hemostasis (excess bleeding)

Answer 29

lab findings of thrombocytopenia (reduction in number of platelets ) or prolonged BT/PFA-100* indicated bleeding disorder of primary hemostasis
- PFA-100 is a modern test version of predcessor BT = bleeding time (im guessing.. the amt of time px bleeds.. a disorder involves prolonged bleeding)

Question 30

what is a mixing study in regards to hemostasis?

Answer 30

regarding hemostasis, a mixing study is used to troubleshoot the cuase of a bleeding/ hemostasis disorder. diff factors mixedinto serum to see if deficiency fixed.. thereby illucidating the source of deficiency.

Question 31

excessive bleeding with trauma indicates what sort of hemostasis disorder?

Answer 31

excessive bleeding w trauma is seen with Either primary or secondary hemostasis.

Question 32

petechia in the mouth is a sign of what type of bleeding disorder?

Answer 32

petechia in the mouth .. which is a clinical manifestation of mucocutaneous bleeding is indicative of primary hemostasis disorder

Question 33

von Willebrand disease, Factor 8 deficiency , and factor 9 deficiency, are examples of CONGENITally acquired bleeding disorders

Answer 33

true.

Question 34

what is the main clinical manifestation of von willebrand’s disease, which is an autosomal dominant disorder

Answer 34

mucocutaneous bleeding is the dominant clinical manifestation of von willebrand disease. )recall, petechia in the mouth are an example of mucocutaneous bleedings.. so may see as a dentist)

Question 35

true/false: Von willebrands disease is only qualitative (poorly functioning Vwb factor)

Answer 35

False. VWB disease can be either qualititive (type 2) or quantitiative (partial = type 1, complete deficiency = type 3)

Question 36

desmopressin, antifibrinolytic agents, factor 8 concetrates, and cryoprecipitate are treatmens for what hemostasis disorder?

Answer 36

these are tretments of von willebrand factor disorder (decreased primary hemostasis bc decreased platelet agregation)

Question 37

what are some clinical manifestations of vwB disorder>?

Answer 37

epistaxis, eccymoses, mucosal bleeding (recall, petechia on RoM) bleeding w surgery/trauma, improved symptoms after adolesence are all characteristics of von willerand disease

Question 38

is Hemophilia A an autosomal dom, auto rec, or sex-linked disorder?

Answer 38

Hemophilia A is a sex-linked disorder and there fore seen clinically manifested in men.

Question 39

what disorder do the ollowing describe:

• recurrent soft tissue bleeding - such as into joints
• syptom onset at less than 5yo (early)
• deficiency of factor 8
• excessive bleeding w trauma, intramuscular and intracellular hemorrhage, bleeding into other tissues

Answer 39

these describe Hemophiia A, a sex-linked disorder

Question 40

if you got the lab results that PFA-100/ BT was prolonged.. would you think von willebrand disease or hemophilia A?

Answer 40

if the PFA-100/BT lab test displayed prolonged bleeding, I would think VWbD since Hemophilia A lab results for PFA-100 are normal. Hemophilia A has a lot of normal test results and only shows a decrease in Factor 7 and prolonged PTT (intinsic pthway clotting time)
-while VwBD has decreased levels of several factors and prolonged bleed times.

Question 41

T/F less than 15% of factor 8 is considered a severe case of hemophilia A

Answer 41

False. Less than 1% of factor 8 is considerred to be a severe case of hemophiia A, where spontaneous and recurent soft tissue bleeding occurs

• moderate cases have 1-5% factor 8. bleeding is seen w mild trauma
• mild has >5% factor 8. bleeding w major trauma

** the less factor 8 present, the more severe the bleeding

Question 42

what 2 therapies are indicated to t hemophila A?

Answer 42

hemophilia A can be treated w delivery of factor 8 concetrates, or fibronlytic inhibitors (prevents clot degredation)

Question 43

T/F Hemophilia B has similar inheritance pattern (sex-linked) and similar clinical manifestation s( intracranial bleeding, bleeding into spaces like the retroperitoneal space, bleeding into joints, pseudoumors, JUST LIKE hemophila A. The difference is that Hemophilia A has a deficiency of ______________ while Hemophilia B hasa deficiency of _________________

Answer 43

True.
Hemophilia A is a deficiency of Factor 8,
Hemophilia B is a deficiency of factor 9

Question 44

The following describes what disorder (choose one):
-decreased platelet production, increased destruction of platelets, congenital and acquired types exist..

Hempphilia B, marfan syndrome, ehler-danlos, thromocytopenia, or hemophilia A

Answer 44

drecreased platelet production/ destruvtion/. sequestration describes thromocytopenia which can be gentically inherited or acquired.

Question 45

what disorder utilizes the following tests:

bone marrow exam, peripheral blood smear?

Answer 45

thrombocytopenia utilizes blood smears, bone marrow exam, history of petechial bleedings, and pletelet antibody determination (if px has autoimmune Ab to the platelets causes their destruction)

Question 46

primarily mucosal bleeding indicatesd a problem of what?

Answer 46

primarily mucosal bleedings is generally indicative of a platelet problem

Question 47

deep tissue hematomas are indicative of a defect in coagulation proteins T/F

Answer 47

True. a defect of coag prtns is often manifested as deep tissue hematomas, while superficial mucosal bleeding indicates a problem w platelets

Question 48

what Inherited bleeding disorder (non-serious bleeding) is the most prevalanet in the US and what is its rate of occurence?

Answer 48

Von Willebrand factor disease is the most common Inherited bleeding disorder affecting about 1% of the US population

• contrast: Hemophilia A is the most common inherited disease for SERIOUS bleeding disorders

Question 49

T/F the following are platelet disorders:
thrombocytopenia, immune thrombocytopenic purpura (ITP), and thrombic throbocytopenic purpura, and DIC disseminated intravascular coagulation

Answer 49

True.

Question 50

What is a misense mutation?

Answer 50

A misense mutation is aka, point mutation. A genetic mutation involving change if a single nucleotide base (atgc).

Question 51

what is microcytic anemia?

Answer 51

microcytic anemia is a reduction in red blood cell mass and IRON DEFICIENCY

Question 52

what is megaloblastic anemia

Answer 52

megaloblastic anemia is a reduction in red blood cell mass due to DEFICIENCY of B12 or FOLATE

Question 53

name three platelet disorders that result in thrombocytopenia

Answer 53

thrombocytopenia is a decreased amt of platelets.(less than 100k/uL= deficient amt)
three platelet disorders w reduced platelets resulting are:
immune thrombocytopenic purpura, thrombotic thromocytopenia purpura, and disseminated intravascular ciagulation

Question 54

what is the most common cause of anemia worldwide?

Answer 54

Iron deficiency is the leading cause of anemia 9decred RBC counbt) worldwide