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SICKLE CELL DISEASE ( scd ). By: Yousef Al Sultan Fatimah Al Khamis. What is SCD?. SCD is a genetic disorders resulting from the presence of a mutated form of hemoglobin in which the body makes sickle-shaped red blood cells. . first described by Herrick in 1910. . etiology.
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SICKLE CELL DISEASE (scd) By: Yousef Al Sultan Fatimah Al Khamis
What is SCD? • SCD is a genetic disorders resulting from the presence of a mutated form of hemoglobin in which the body makes sickle-shaped red blood cells.. first described by Herrick in 1910.
etiology • SCD is an autosomal recessive disorder of hemoglobin in which the β subunit genes have a missense mutation causing the substitution of valine for glutamine at amino acid 6. most commonly due to homozygosity for the sickle cell mutation, although genetic compound between the sickle allele and a hemoglobin C or a βthalassemia allele can also have the disease.
Sickle cell trait • People who inherit a sickle hemoglobin gene from one parent and a normal gene from the other parent have sickle cell trait. Their bodies make both sickle hemoglobin and normal hemoglobin. • People who have sickle cell trait usually have few, if any, symptoms and lead normal lives. However, some people may have medical complications
diagnosis • by the typical clinical picture of chronic hemolytic anemia and vaso-occlusive crisis. • Electrophoresis confirms the diagnosis with the presence of homozygous HbS
Signs & symptoms • Signs and Symptoms Related to Anemia: • Shortness of breath • Dizziness • Headaches • Coldness in the hands and feet • Paler than normal skin or mucous membranes • Jaundice • Vaso-occlusive crisis. • Splenic sequestration crisis. • Aplastic crisis. • Haemolyticcrisis.
Complications SCD can lead to: • Stroke • Avascular necrosis of major joints • Osteomyelitis • Chronic renal failure • Pulmonary hypertension • During pregnancy, intrauterine growth retardation, spontaneous abortion, and pre-eclampsia
epidemiology • Figure: The hatched line represents the distribution of malaria. The various red colors represent the relative frequency of sickle cell allele in the population with the dark red having the highest frequency and the light red having the lowest frequency.
Management • The goals of treatment are symptom control and management of disease complications. • Bone marrow transplantation is the only treatment currently available that can cure sickle cell disease.
prevention • sickle-cell screening and genetic counseling programs in high prevalence countries. Ideally, the disease should be identified during the prenatal period or at birth as part of a routine screening program which can lead to substantial reduction in the number of children born with the trait.
References • Thompson & Thompson GENETICS in MEDICINE • http://cnx.org/content/m47293/latest/ • http://www.sicklecell.howard.edu/ABriefHistoryofSickleCellDisease.htm • http://upload.wikimedia.org/wikipedia/commons/3/3e/Autorecessive.svg • http://emedicine.medscape.com/article/205926-overview#aw2aab6b2b2 • http://www.afro.who.int/en/clusters-a-programmes/dpc/non-communicable-diseases-managementndm/programme-components/sickle-cell-disease.html