![]() ![]() Genetic studies in Brazil have also tied the origin of such patients to the slave trade originating from West Africa (Mina Coast and Angola). This is true for several countries where patients with SCD and SCA are living. ![]() ![]() Besides, migration within the country and immigration from foreign countries alter the prevalence of SCD and HbAS. The incidence varies by state and geographical concentration of ethnicities. Children and adolescents make up to 40% of all SCD patients in the US. The estimated ratio of Hispanic Americans with SCD is 1 in 16,300. ![]() The CDC also estimates that 1 in 13 babies born to African-American parents have sickle cell trait, and 1 in 365 African-Americans have SCD. The United States (US) Center for Disease Control (CDC) estimates that approximately 100,000 Americans have SCD. West Africa is home to the largest population of individuals with HbSC disease. an estimated 75% of SCD-related births take place in sub-Saharan Africa. It is estimated that ~230,000 children were born with SCA, and more than 3.5 million neonates were born with HbAS in sub-Saharan Africa in 2010. It is well known that SCD and HbAS are more prevalent in sub-Saharan Africa, where the carrier of HbAS is afforded natural protection against severe Plasmodium falciparum malaria. The epidemiological data on SCD is scarce. HbSC disease accounts for 30% of patients in the United States. HbC is formed when lysine replaces glutamine at the sixth position on the beta-globin chain. The second most common variant of SCD is the HbSC disease, where the sickle cell gene is coinherited with a single copy of the mutated hemoglobin C gene. Several other compound heterozygotes exist where a single copy of the mutated beta-globin gene is coinherited with a single copy of another mutated gene. They might only be detected during childbirth, blood donation, or screening procedures. Patients with HbAS are not considered within the spectrum of SCD as most of them never present with typical symptoms of SCA. The coinheritance of beta-naught thalassemia and sickle cell mutation leads to HBS-Beta-0 disease, which phenotypically behaves like HBSS disease.Ī heterozygous inheritance leads to HbAS. A homozygous mutation leads to the severest form of SCD, i.e., SCA- also called HBSS disease. The mutation is transmitted via Mendelian genetics and is inherited in an autosomal codominant fashion. The sickle cell mutation occurs when negatively charged glutamine is replaced by a neutral valine at the sixth position of the beta-globin chain. HbF- comprises two chains of the alpha-globin and two chains of the gamma-globin (a2g2) - This Hb is more prevalent in the fetus (due to the high oxygen binding affinity that helps extract oxygen from maternal circulation). Since then, the treatment of sickle cell has taken to new heights by introducing several new agents (voxelotor, crinzalizumab, L-glutamine) and, most recently, gene therapy. first reported the use of hydroxyurea in increasing the levels of HbF. Recent advances in the field, more so within the last three decades, have alleviated symptoms for countless patients, especially in high-income countries. In 1984, Platt et al. Since the first description of the irregular sickle-shaped red blood cells (RBC) more than 100 years ago, our understanding of the disease has evolved tremendously. Sickle cell anemia is the most common form of SCD, with a lifelong affliction of hemolytic anemia requiring blood transfusions, pain crises, and organ damage. Lastly, it is essential to mention the sickle cell trait (HbAS), which carries a heterozygous mutation and seldom presents clinical signs or symptoms. Several other minor variants within the group of SCDs also, albeit not as common as the varieties mentioned above. Within the umbrella of SCD, many subgroups exist, namely sickle cell anemia (SCA), hemoglobin SC disease (HbSC), and hemoglobin sickle-beta-thalassemia (beta-thalassemia positive or beta-thalassemia negative). Linus Pauling described the molecular nature of sickle hemoglobin (HbS) in his paper 'Sickle Cell Anemia Hemoglobin.' Ingram Vernon, in 1956, used a fingerprinting technique to describe the replacement of negatively charged glutamine with neutral valine and validated the findings of Linus Pauling. Beet described the patterns of inheritance in patients with SCD. Ernest Irons reported noticing 'sickle-shaped' red cells in a dental student (Walter Clement Noel from Grenada). Africanus Horton in his book The Disease of Tropical Climates and their treatment (1872). Sickle cell disease (SCD) refers to a group of hemoglobinopathies that include mutations in the gene encoding the beta subunit of hemoglobin. The first description of SCA 'like' disorder was provided by Dr. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |