Thalassemias Flashcards
Define haemoglobinopathies.
Disorders of Hb
What is the most common haemoglobinopathy?
HbS - sickle cell disease
Define thalassemia.
Genetic diseases resulting in reduced production of either alpha or beta globin chain of Hb. Reduced transport of oxygen in the body.
Name the three different severity types of thalassemia.
Major
Intermedia
Minor/Trait
Describe the qualities of thalassemia major.
Anaemia Splenomegaly Abnormal bone development Iron overload Life expectancy <3 years if untreated 30+ years if treated
Which ethnic groups have a higher risk of being carriers?
B - asian, african, mediterranean
What are supposed benefits of being carriers of thalassemia?
Decreased risk of malaria
What type of carriers are Maori likely to be?
Alpha trait carriers
What type of anaemia are carriers likely to have?
Microcytic anaemia, but often no significant disease
What is the treatment for thalassemia?
Blood transfusion, but issue of iron overload - therefore need chelation therapy.
Cure - bone marrow (stem cell) transplant
What can mild cases be treated with?
Intermedia can be treated with hydroxyurea to increase the expression of gamma fetal form.
What are other possible treatments for thalassemia?
Drugs that promote RBC formation and CRISPR to correct or raise the gamma in trials.
State the effects of non-silent globin mutations.
Decreased/Loss of function mutations - autosomal recessive
Abnormal/Gain of function - autosomal dominant
Novel properties e.g. HbS
Ectopic gene expression
What are the public health approaches to preventing thalassemia?
Population screening for carriers (microcytic anaemia)
What are the ethical and social issues regarding screening?
Large numbers, developing countries, autonomy and consent, results affect marriage and reproduction, differing effectiveness of programs in different countries.
