Haemophilia And Genetic Basis

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Definition Haemophilia and Genetic basis: Haemophilia is a bleeding disorder where the person’s blood clots ineffectively causing spontaneous or injury induced unnaturally rapid internal and external bleeds. This is a result of a severe lack of various clotting factors, depending on type, in the blood. A clotting factor is a protein in blood that controls bleeding. Haemophilia is described as being of sex-linked inheritance and is passed down through the family genes. There are three types of Haemophilia; Haemophilia A, B and C. Haemophilia A is the most common type and caused when there is a reduction in clotting factor VIII in the blood. Haemophilia B is caused by factor IX. Although they are cause by different clotting factor deficiencies…show more content…
This type differs from haemophilia A and B as there is no bleeding into joints and muscles. Another difference is that unlike factor VIII and IX deficiencies in the other Hemophilia types, factor XI Ievels n the blood don’t predominately correlate with its bleeding severity in the patient. “What is characteristic of factor XI deficiency is that you can have a severe factor XI deficiency with a level of less than 1% and be asymptomatic,” says Ann Hurlet-Jensen, MD, associate professor, pediatric hematology-oncology, Mount Sinai School of Medicine in New York. “On the other hand, you can have a level in the 30% to 40% range and have bleeding.” Although it is most often that those with the Haemophilia disorder display little and varied visible symptoms making early diagnosis and treatment difficult. It is also of autosomal recessive inheritance in which two recessive afflicted alleles are needed to produce afflicted offspring, thus affecting males and females with equal…show more content…
These chromosomes are possessed by every human and determine their offspring’s gender and genetic material such as alleles for appearance. Males possess a ‘XY’ pair; ‘Y’ from the father and ‘X’ from the mother, whilst females possess ‘XX’ pair; one ‘X’ from each parent. Genes concerning blood clotting are contained in the X chromosome, thus making haemophilia an ‘X’-linked disorder. Due to this afflicted female can pass on the disorder to their offspring of both genders as they all receive an ‘X’ chromosome from the mother; however afflicted men can only pass on haemophilia to his daughters as the male gives off ‘X’ chromosomes to his daughters but ‘Y’, which can’t contain the genetic disorder, to his sons. However, the haemophilia disorder is recessive to that of the dominant normal blood clotting gene, thus meaning a female would need an afflicted ‘X’ chromosome from both parents, in which the female will have inherited the disease through a homozygous pairing of alleles. Homozygous is when an individual carries two of the same alleles3 on a certain gene. A recessive gene will only become apparent when this homozygous state is in occurrence. If a normal ‘X’ chromosome is present then it will dominate over the recessive disordered gene and provide enough clotting factor to make up for the other’s lack of. This dominance over another allele when both different alleles
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