Sickle cell anemia is a genetic blood disorder that causes the red blood cells to become abnormally shaped, leading to a variety of complications.

It is widespread among populations from regions where malaria is endemic, including parts of Africa, India, and the Middle East.

In the Mediterranean region, the most frequent form of sickle cell disease is known as beta-thalassemia or Mediterranean anemia.

It is a genetic disorder caused by a mutation in the beta-globin gene, which encodes the protein subunit of hemoglobin, the molecule responsible for carrying oxygen to the body’s tissues. This mutation leads to reduced or absent beta-globin production, resulting in anemia in affected individuals.

Genetics of Mediterranean anemia

Beta-thalassemia is an autosomal recessive disorder, which means that a person must inherit two defective copies of the beta-globin gene, one from each parent, to develop the disease.

If a person inherits only one mutated copy, they are carriers of the disease, but do not have any symptoms themselves. Carriers have a 25% chance of having an affected child with each pregnancy, a 50% chance of having a carrier child, and a 25% chance of having a non-affected non-carrier child.

The frequency of carriers differs among populations. In the Mediterranean region, it is estimated to be around 1-10%, depending on the specific countries and regions, but it can be as high as 50% in some communities.

Signs and symptoms of Mediterranean anemia

The severity and presentation of Mediterranean anemia can vary widely depending on the specific mutations involved and their interactions with other genetic or environmental factors.

In general, the disease leads to impaired red blood cell production, causing anemia, and an imbalance of alpha- and beta-globin chains, resulting in the formation of abnormal hemoglobin molecules and increased destruction of red blood cells.

Common signs and symptoms include:.

• Chronic anemia, which can cause fatigue, weakness, and pallor
• Jaundice, due to increased breakdown of red blood cells and accumulation of bilirubin
• Enlarged spleen and liver, as the organs try to clear the damaged red blood cells
• Bone deformities, especially in the skull and the face, due to expansion of the bone marrow to cope with increased red blood cell production in the fetal and early childhood period
• Delayed puberty and growth, due to hormonal imbalances and chronic inflammation caused by the disease

Complications of Mediterranean anemia can include:.

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• Iron overload, due to repeated blood transfusion or increased iron absorption from the diet, which can damage organs such as the heart, liver, and pancreas
• Infections, especially by encapsulated bacteria such as Streptococcus pneumoniae, which can cause severe sepsis and meningitis
• Pain crisis, due to the blockage of blood vessels by the sickle-shaped red blood cells, which can lead to tissue damage and organ failure

Diagnosis

The diagnosis of Mediterranean anemia involves several steps, including:.

• A blood test to measure the levels of hemoglobin, red blood cells, and other markers of anemia
• A genetic test to check for the presence of beta-thalassemia mutations
• Additional tests, such as a bone marrow biopsy or an echocardiogram, may be necessary to determine the extent of the disease and its complications.

Treatment and management

The treatment and management of Mediterranean anemia depend on the severity of the disease, the age of the patient, and the presence of complications.

In mild cases, such as beta-thalassemia minor or carriers, no treatment may be necessary, other than regular monitoring of the blood counts and genetic counseling for family planning.

In more severe cases, such as beta-thalassemia major or intermediate, various strategies may be used to alleviate the anemia and prevent complications:.

• Blood transfusion: Regular blood transfusion, usually every 2-4 weeks, can help restore the hemoglobin levels and improve the symptoms of anemia. However, it can also lead to iron overload, which requires chelation therapy to remove the excess iron from the body
• Bone marrow transplant: A bone marrow or stem cell transplant from a compatible donor can provide a cure for Mediterranean anemia, by replacing the defective beta-globin genes with healthy ones. However, this procedure carries significant risks and may not be feasible for all patients.
• Iron chelation therapy: To reduce the risk of iron overload and its complications, iron chelation therapy, such as deferoxamine or deferasirox, can be used to remove excess iron from the body.
• Vaccinations: To prevent infections, patients with Mediterranean anemia should receive regular vaccinations against common pathogens, such as pneumococcus, meningococcus, and influenza.
• Supportive care: Patients with Mediterranean anemia may require additional supportive care, such as folic acid supplements, pain control, or hormone replacement therapy.

Prevention and screening

The best way to prevent Mediterranean anemia is to identify carriers and at-risk couples through genetic screening and counseling.

Preconception testing can detect carriers of the beta-thalassemia gene, and the results can inform decisions about family planning, such as choosing a partner who is not a carrier, undergoing in vitro fertilization with preimplantation genetic diagnosis, or prenatal testing during pregnancy.

In countries with a high prevalence of Mediterranean anemia, newborn screening programs can identify affected infants early and provide appropriate treatment and follow-up.

Screening tests typically involve measuring the levels of hemoglobin and other blood markers from a few drops of blood from a heel prick within the first few days of life.

Educating the public about the genetic basis and consequences of Mediterranean anemia can also help reduce the stigma and discrimination faced by affected individuals and promote inclusive and supportive communities.

Conclusion

Mediterranean anemia is a genetic blood disorder that affects millions of people worldwide, primarily in the Mediterranean region.

It can cause a range of symptoms and complications, but early diagnosis and appropriate treatment can alleviate the impact and improve the quality of life for affected individuals. Preventing the disease through genetic screening and counseling can also reduce its burden on families and society.