About SCD & Thalassemia
About Sickle Cell
Sickle Cell Disease is a genetic blood disorder found in people with African, Caribbean, Central/South American, East Indian, Middle Eastern, Mediterranean, Asian, and Southeast Asian ancestry. The disease is linked to malaria and has developed over thousands of years as a natural immune response to the disease. Individuals with sickle cell disease can experience severe, frequent pain episodes starting from the age of 6 months, often requiring hospitalization for treatment.
These crisis episodes can last for weeks or even months and may lead to severe disability or death, despite adequate medical care. The disease causes anemia, oxygen deprivation, poor circulation, and extreme pain. It is associated with various complications.
- Organs most commonly damaged by severe anemia are the heart, lungs, brain, and eyes.
- Pulmonary complications like acute chest syndrome and pulmonary hypertension.
- Enlargement and damage of the spleen (life threatening, especially in children).
- Dysfunction or acute failure of the kidneys or liver.
- Upper and lower extremities – are at risk to develop arm and leg ulcers.
- Damage to tissue and bone due to diminished blood flow and loss of oxygen (ischemic damage). Avascular Necrosis is a degenerative complication affecting the shoulders and hips joints. In the most advanced state hip replacements are required.
About Thalassemia
Thalassemia is a group of genetic disorders characterized by abnormal hemoglobin variants. The two most common types are Alpha Thalassemia (Cooley’s Anemia) and Beta Thalassemia. Alpha Thalassemia results in severe anemia due to low production of alpha (α)-globin beta proteins in red blood cells. This leads to the breakdown of red blood cells and a deficiency in their production, causing severe anemia. People with Alpha Thalassemia often require regular transfusions to maintain their health.
Beta Thalassemia, on the other hand, involves a deficiency in beta (β)-globin proteins in hemoglobin. Symptoms of Beta Thalassemia include jaundice, extreme fatigue, enlarged heart and liver, bone deformities, organ damage, and an increased risk of developing diabetes. Children diagnosed with Beta Thalassemia need regular blood transfusions to survive. There is also a milder form called Hemoglobin H disease (Hb AH). Thalassemia hemoglobin variants are found in various regions, including Africa, Southeast Asia, China, India, Greece, Italy, Eastern Europe, and the Middle East.
About Rare Disorders
In the United States, a rare disease is defined as a condition, whether inherited or acquired, that affects fewer than 200,000 people. This definition was established by Congress in the Orphan Drug Act of 1983, which aimed to incentivize the development of treatments for rare diseases. Previously, these diseases were referred to as orphan diseases because pharmaceutical companies showed little interest in developing treatments for them. The Orphan Drug Act introduced financial incentives to encourage companies to invest in researching and producing drug therapies for rare diseases. The specific definition was necessary to determine which conditions would qualify for the new incentive programs.
It’s important to note that the definition of rare disease may vary in other countries. In the European Union, for example, a rare disease is defined as a condition that affects fewer than 1 in 2,000 people.
In the United States, approximately 7,000 rare diseases have been identified, impacting an estimated 25-30 million individuals. This statistic is often used by the Rare Disease Community to highlight the significant impact inherited disorders have on individuals and families throughout the country.
Abnormal Hemoglobin Traits
There are more than 400 unusual hemoglobin (Hb) genes associated with sickle cell disease and other hemoglobin variants. In the United States, millions carry a trait (one usual hemoglobin A gene, and one of more than 25 sickle hemoglobin gene traits.
The main abnormal hemoglobin gene trait associated with sickle cell syndromes is called Hemoglobin S (HbS). Sickle cell disease occurs when an individual inherits two copies of the HbS gene, one from each parent. Hemoglobin S causes red blood cells to become misshapen and rigid under certain conditions, leading to the characteristic sickle shape of the cells. This can result in a variety of complications, including pain crises, anemia, organ damage, and increased susceptibility to infections.
Apart from Hemoglobin S, there are other abnormal hemoglobin gene traits related to sickle cell syndromes. These include Hemoglobin C (HbC), Hemoglobin D (HbD), and Hemoglobin E (HbE). These traits can occur in combination with Hemoglobin S, resulting in different subtypes of sickle cell disease, such as Hemoglobin SC disease (involving HbS and HbC), Hemoglobin SD disease (involving HbS and HbD), and Hemoglobin SE disease (involving HbS and HbE).
It’s worth noting that there are other types of abnormal hemoglobin gene traits unrelated to sickle cell syndromes, such as Hemoglobin E trait (HbE trait) and Hemoglobin C trait (HbC trait), which are usually benign carriers of the traits without significant health complications. The geographic origins of each of the mentioned sickle cell traits (SCT) are as follows:
- Hemoglobin S (HbS): The sickle cell trait associated with sickle cell disease has its origins in regions where malaria is endemic. Outside of Sub-Saharan Africa, SCTs are particularly found in populations from West and Central Africa. Hb S is also most commonly found in:
- Middle Eastern countries such as Israel, Saudi Arabia, Yemen, Jordan, and Oman.
- The Mediterranean in Greece, Italy, and Turkey.
- India in regions with tribal communities in central and eastern India.
It’s important to note that the prevalence and distribution of HbS does vary within these regions.
- Hemoglobin C (HbC): The HbC trait is prevalent in regions of West Africa, including countries like Mali, Burkina Faso, Ivory Coast, and Liberia. It is also found in those of Mediterranean descent. South America, specifically in areas with African ancestry, such as parts of Brazil, Suriname, Guyana, and French Guiana. Caribbean populations with a significant prevalence of HbC, include countries like Jamaica, Haiti, and the Dominican Republic.
- Hemoglobin D (HbD): The HbD trait is primarily found in populations from regions of India, Pakistan, and Iran. It is more commonly seen in individuals of South Asian descent. Hb D is found among various Indian ethnic groups, Napal, Pakistan, and Bangladesh.
- Hemoglobin E (HbE): The HbE trait is prevalent in populations from Southeast Asia, particularly in regions such as:
- Thailand, Cambodia, Laos, Vietnam, and Myanmar.
- Northeast India, particularly in states such as Assam, Manipur, Nagaland, and Mizoram. Bangladesh.
- Southern China in Guangxi, Guangdong, and Yunnan provinces.
It’s important to note that while sickle hemoglobin traits have specific geographic associations, traits vary due to migration and intermixing of populations have led to their presence in other regions where malaria is not endemic, like in the United States, Canada, and Europe.
The three most common sickle traits worldwide are S trait (Hb AS), C trait (Hb AC) and Beta Thalassemia trait (Hb β-Thalassemia), and Alpha Thalassemia (Hb α-Thalassemia).
Sickle Cell Traits, worldwide with a prevalence greater than one percent (1%) of a given population.
Hemoglobin Traits S,C, D, E & β Thalassemia
Africa
North – Hb AS, Hb AC, Hb AD
East – Hb AS, Hb AC Hb β Thal, Hb AD
West – Hb AS, Hb AC, Hb β Thal, Hb AD
South – Hb AS, Hb AC, Hb AD
Mediterranean
Greece – Hb AS, Hb β Thal
Italy – Hb AS, Hb AC, Hb β Thal
Turkey – Hb AS, Hb AC, Hb β Thal
Americas
North – Hb AS, Hb AC, Hb β Thal, Hb AE
Central – Hb AS, Hb AC, Hb AD
South – Hb AS, Hb AC, Hb AD
Middle East
Saudi Arabia – Hb AS, Hb β Thal, Hb SO
Israel – Hb AS, Hb AC, Hb β Thal
Jordan – Hb AS, Hb AC
Pakistan – Hb AS, Hb AC
Caribbean
African – Hb AS, Hb AC, Hb β Thal
Latino – Hb AS, Hb AC, Hb β Thal, Hb AD
Southeast Asia
Cambodia, Laos, and Vietnam
𝞪 Thalassemia, ꞵ Thalassemia, Hb E, and HB Constant Springs (Hb CS)
SCTPN Affiliate & Chapters
New York State
Amina K. Sickle Cell Support Circle of Harlem, Chapter
SCTPN Albany, Chapter (In development)
Sickle Cell Advocates of Rochester (SCAR), Affiliate
Regional Affiliates
SCTPN St. Thoma, USVI, Chapter
International Affiliates
Belize Sickle Cell Disease Foundation, (BSCDF) Central America
Gambia Sickle Cell Association, (GSCA) Gambia, West Africa
Raising Hope International Friends (RHIF), Uganda, East Africa