Hereditary Hemolytic Anemia

The Department

Hemoglobinopathies are inherited hemoglobin disorders which can be split into two major categories:

1. Thalassemias, formerly known as Mediterranean anemias, which were coined from the Greek word thalassa (sea), since the condition was first observed in people of Mediterranean ethnicities

2. Anemias due to abnormal structure of the hemoglobin, such as sickle-cell anemia, microdrepanocytic anemia and other rare hemoglobinopathies

Thalassemias and drepanocytic anemias are the most commonly encountered single-gene blood disorders worldwide, so diagnosis and treatment of patients constitutes a major public health issue. A child or adult may be a carrier of one of the syndromes (heterozygous) or may be affected by them (homozygous) due to the combination of two carriers. Carriers (heterozygous) are not affected. Only homozygous individuals are affected.

The clinical condition of homozygous patients is quite diverse. The gravity of the clinical symptoms greatly relates to the genetic disorder. There are patients with mild clinical condition, while a large proportion of patients may demonstrate severe clinical condition and may require systematic treatment from infancy, through blood transfusions.

The main problem in these patients is severe anemia due to decreased hemoglobin production, as well as continuous reduction of erythrocytes (red blood cells) due to hemolysis.

Around 7% of the population are carriers of various hemoglobinopathies. According to World Health Organization (WHO) statistics, approximately 500,000 new cases are diagnosed annually.

It is estimated that 8% of the population in Greece are carriers of alpha and beta thalassemias. Their distribution is heterogeneous and varies from 5% to 20% in certain areas.

In countries such as Greece, where these disorders are considered endemic, safe and reliable diagnosis is more than imperative.

A modern hemoglobinopathy diagnosis center operates within the central labs. Diagnosis of these anemias, mainly in childhood, is based on a series of general and special lab tests. The whole family often needs to be tested for safer diagnosis.

The lab tests include:

• blood tests (complete blood count, red blood cell morphology, assessment of red blood cell indices, reticulocyte count, assessment of reticulocyte indices)
• iron and plasma ferritin levels
• quantitative analysis of hemoglobin (Hb) A2, F, S and other hemoglobin variants
• HbF distribution per red blood cell (Kleihauer-Betke test)
• staining for HbH inclusion bodies
• staining for Heinz bodies
• unstable hemoglobin test
• erythrocyte osmotic fragility
• sickle-cell test
• hemoglobin electrophoresis. The labs are equipped with an extremely accurate state-of-the-art capillary electrophoresis system just for this test. The device requires a very small blood sample (18 μl) for fast (sample electrophoresis within 6 minutes) and excellent separation of hemoglobins, as well as identification of an array of hemoglobin variants (C, D, E, G, O-Arab, etc). This ensures accurate diagnosis of all hereditary hemolytic anemias.

Hemoglobinopathy diagnosis is a complex process that requires evaluation of all lab findings and clinical data. In terms of public health, prevention is the key to limiting hemoglobinopathies. This means early, accurate and reliable diagnosis of carriers (heterozygous), as well as proper genetic guidance to prevent the birth of affected children.