1. SECTIONS:
2. preface & acknowledgements
3. genetics at a glance
4. contacts, support & testing
5. testing & pregnancy
6. newborn screening
7. cancer in the family
8. cardiovascular conditions
9. chromosomal conditions
10. clotting & bleeding conditions
11. cystic fibrosis
12. diabetes
13. fragile X syndrome and other causes of developmental delay
14. haemoglobinopathies
15. hereditary haemochromatosis
16. neurofibromatosis
17. neurological conditions
18. psychiatric conditions
19. genetics in practice
20. emerging genetic technologies
21. glossary

Investigations

1. See Investigations of carriers for haemoglobinopathies in general.
   
2. Genetics Services or haematologists can provide advice regarding appropriate testing.

 

For affected individuals

1. FBE usually shows significant anaemia, microcytosis, hypochromia and abnormal red cell morphology, including target cells. Nucleated red blood cells are usually present.
   
2. Haemoglobin electrophoresis testing to determine HbF and HbA2 levels is usually diagnostic of
   β-thalassaemia. Affected children over the age of six months usually have markedly elevated levels of
   HbF and elevated HbA2.
   
3. Compound heterozygous states result in a variety of abnormal results on haemoglobinopathy testing.
   Contact a haematologist for advice.

 

For potential or identified carriers

1. It is considered good practice to investigate all women of childbearing age with FBE and ferritin, and Hb electrophoresis for women from an at-risk group (see Figure 2).
   
2. Investigation for β-thalassaemia carrier state is usually a multi-step process, with results of FBE, ferritin studies and clinical picture influencing decisions regarding haemoglobinopathy testing and DNA analysis.
   
3. All indications for investigation should be given, including pregnancy, gestation, ethnicity and family history, to assist the laboratory in interpreting test results.

 

In couples where both partners are carriers for β-thalassaemia, referral to a specialist service for information about their risk of having an affected pregnancy should be arranged.

 

Management

1. Treatment and management is performed by specialist services.
   
2. Patients with β-thalassaemia major require regular blood transfusions every three to four weeks for their whole life.
   
3. Excess iron is eliminated from the body by iron-chelating agents (eg desferrioxamine, administered by subcutaneous infusion pump), with oral chelating agents now available to supplement or replace desferrioxamine.
   
4. A ‘no added iron’ diet is recommended.
   
5. The majority of complications associated with β-thalassaemia major are due to iron build-up, despite chelation therapy, or marrow expansion.
   
6. Splenectomy may be performed because of enlargement. These patients require the same immunisation as other children and prompt treatment of infections.
   
7. Bone marrow transplantation may cure β-thalassaemia major but has a significant risk of complications
   and mortality.
   
8. The life expectancy of well-treated, compliant patients is not known but is likely to be normal or near normal.
   
9. Carriers for β-thalassaemia should have folic acid (5 mg) daily throughout all pregnancies.
   
10. Carriers for β-thalassaemia must not have long-term iron treatment to attempt to cure microcytosis, unless they are also iron deficient.

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