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Hemophilia - Answers

1. Vasoconstriction, the formation of a platelet plug, and secondary hemostasis.

2. Adhesion, platelet release reaction, and platelet aggregation.

3. The intrinsic, extrinsic, and common pathways.

4. Tissue damage

5. Damage within the vessel

6. The formation of fibrin threads

7. The Intrinsic pathway is affected.

8. Elevated: Certain malignancies (i.e. leukemia), certain blood disorders, and rheumatoid arthritis.
Decreased: Certain blood disorders, infections, and some medications.

9. A test that measures how long a person takes to stop bleeding after several small cuts are made on the lower arm.

10. Extrinsic pathway

11. Intrinsic pathway

12. Medical laboratory scientist.

13. Because the APTT was the only abnormal result, the physician would suspect a factor involved in the intrinsic pathway, factor VIII, IX, XI, or XII.

14. He has less than 1% of factor VIII present in his blood.

15. How often a person will bleed, how difficult it will be for them to form a clot, and how much medication they will need to control their bleeding.

16. Female

17. Male and female

18. 50% in both cases. A female carrier has two x chromosomes, one of them carries the hemophilia trait. She will pass this to half of her sons who will have the disease, and half of her daughters who will be carriers.

19. The hemophilia trait is carried on the x chromosome. Males have only one x chromosome, therefore, if they have the hemophilia trait on the x chromosome they will have the disease. Females have two x chromosomes, if they have the hemophilia trait on one x chromosome they are carriers of the disease but generally do not display symptoms.

20. His sons will not have hemophilia, all of his daughters will be carriers. Hemophilia is carried on the x chromosome. A male has an xy chromosome, a female xx. The hemophilia trait is linked to the x chromosome. He would pass the y chromosome to his sons and the x to his daughters.

21. Freeze-dried factor VIII concentrate was the method of choice for replacement. This concentrate was pooled from multiple plasma donors, thus greatly increasing the risk for viral contamination. The HIV virus was not screened for at the time.

22. By manufacturing factor VIII through genetic engineering.

23. The DNA for Factor VIII is cloned into bacterial DNA. The bacteria now produce Factor VIII. The bacteria multiply rapidly producing great quantities of factor VIII which is free from any viral contamination.

24. Gene therapy uses viruses as vectors to insert missing genetic material directly into the patient's own cells. By inserting the missing genetic material that codes for factor VIII, patient's may produce factor VIII on their own. Gene therapy is undergoing experimental trials in humans and is hoped to be a cure for hemophilia.

25. Liver cells or sometimes other cells are removed from the patient with hemophilia. Scientists insert new genetic material into the cells with the genetic material to produce factor 8 or 9. The cells are reinserted into the patient with hemophilia and the patient can now produce the missing clotting factor.

26. Successful human studies have been done inserting factor IX into cells through adeno-associated viral vectors. Factor VIII is more problematic. Genetic transfer of both factof VIII and factor IX are still in trials.

27. A gene is a working subunit of DNA.

28. DNA is a chemical information database made up of 2 strands containing chemical bases. DNA carries the genetic code to make specific proteins.

29. A chromosome is a pair of structures in a cell that house the DNA. Each cell contains 22 autosomes and 1 pair of sex chromosomes (xx female, xy male).

30.  A genome is the entire DNA sequence

30. A gene varient is a permanent change in the DNA sequence that makes up a gene (also called a gene mutation).  Gene varients may be inherited or non-inherited.  Environmental factors such as ultraviolet radiation can cause non-inherited varients.

31. Genetic testing examines DNA and can reveal changes in genes that may cause illness or disease.

32.  Genetic testing can determine the risk of developing certain disease.  It can also be used for screening and also may be used for medical treatment.  Different types of genetic testing include: 
*diagnostic testing (can reveal if there is a disorder present),
*predictive testing (identifying risk for a certain disease),
*carrier testing (detects genes that are recessive but may cause disease in the offspring if carried by both spouses),
*pharmacogenetics (can determine what medication and dosage is most effective for an individual patient),
*prenatal testing (can detect genetic abnormalities in baby's genes),
*preimplantation testing (used to screen embryos for genetic abnormalities if in vitro fertilization is utilized).

33.  Diagnose a specific disease or condition and help determine a treatment plan.  Find out if patient is carrying a gene that could cause a disease in their child.  Determine the liklihood of developing a certain disease.

34.  Boys inherit the gene varient from their mother who is a carrier of the gene.