A guide for health professionals working with
immigrant and refugee children and youth

Thalassemia

Key points

  • Thalassemia encompasses a group of hematologic disorders in which alpha- or beta-globin production is reduced or absent. The resulting quantitative red cell disorder is referred to as alpha or beta thalassemia, respectively. This genetic disorder can be caused by one or several gene mutations. Its phenotypes range from silent to fatal.
  • All patients with thalassemia should be cared for by a multidisciplinary team who can access red cell transfusion, monitor for cardiac, liver, endocrine and bone complications, and manage such complications as they arise. Access to a hematopoietic stem-cell transplant centre and transition services to adult care should also be considered.

Epidemiology

The maps below show the prevalence of alpha and beta thalassemias.

Figure 1. Global distribution of α- and β- thalassemia

Global distribution of α- and - thalassemia

Source: Weatherall, DJ. Phenotype-genotype relationships in monogenic disease: Lessons from the thalassaemias. Nature Reviews Genetics 2001;2(4):245-55.

Alpha thalassemias

Silent carriers of alpha thalassemia — people who have the alpha-thalassemia trait — usually do not require treatment. Their genetic and clinical characteristics are summarized in this table.

Table 1: Genetic and clinical characteristics of alpha thalassemias

Variant

Chromosome 16,
gene deletions

Signs and symptoms

Alpha thalassemia silent carrier

One of four

Asymptomatic

Alpha thalassemia trait

Two of four

Asymptomatic

Hemoglobin Constant Spring

Reduced output of alpha globin

Silent or mildly symptomatic

Alpha thalassemia intermedia with significant hemoglobin H (hemoglobin H disease)

Three of four

Moderate-to-severe hemolytic anemia, a modest degree of ineffective erythropoiesis, splenomegaly, variable bone changes

Alpha thalassemia major with significant hemoglobin (Hb Bart’s)

Four of four

Causes nonimmune hydrops fetalis, usually fatal

Reprinted with permission from Alpha and beta thalassemia, August 15, 2009, Vol. 80, No. 4, American Family Physician Copyright ©2009 American Academy of Family Physicians. All Rights Reserved.

Beta thalassemias

Individuals with the beta-thalassemia trait (one gene affected) usually do not require treatment. Patients who have beta thalassemia major (two beta-globin genes affected) are usually transfusion-dependent from an early age and later require chelation therapy due to subsequent iron overload. Iron supplements should be avoided by people who have thalassemia mutations except when a child has proven iron deficiency.  Iron loading is a serious complication of thalassemia major and intermedia.

Preconception genetic counselling should be offered to those at risk of having a child with thalassemia.1

Table 2: Genetic and clinical characteristics of beta thalassemias

Variant

Chromosome 11,
gene defects

Signs and symptoms

Beta thalassemia trait

One

Asymptomatic

Beta thalassemia intermedia

Two; mild-to-moderate decrease in beta-globin synthesis

Variable degrees of severity of symptoms of thalassemia major

Beta thalassemia major

Two; severe decrease in beta-globin synthesis

Abdominal swelling, growth retardation, irritability, jaundice, pallor, skeletal abnormalities, splenomegaly; requires lifelong blood transfusions

Reprinted with permission from Alpha and beta thalassemia, August 15, 2009, Vol. 80, No. 4, American Family Physician Copyright ©2009 American Academy of Family Physicians. All Rights Reserved.

Management of thalassemia

Canadian guidelines for the care of patients with thalassemia are available.1

All patients with thalassemia should be cared for by a multidisciplinary team who can access red cell transfusion, monitor for cardiac, liver, endocrine and bone complications, and manage such complications as they arise. Access to a hematopoietic stem-cell transplant centre and transition services to adult care should also be considered.

Selected resources

References

  1. Sayani F, Warner M, Wu J, et al, 2009. Guidelines for the clinical care of patients with thalassemia in Canada.

Editor(s)

  • Andrea Hunter, MD
  • Anna Banerji, MD

Last updated: May, 2013

Also available at: http://www.kidsnewtocanada.ca/conditions/thalassemia
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Caring for Kids New to Canada is a resource for health professionals. The information here is not a substitute for medical advice, nor does it indicate an exclusive course of treatment or procedure to be followed. Variations, taking into account individual circumstances, may be appropriate.

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