Think Foundation
Knowledge Centre - Thal. Minor Facts

...is about healthy youngsters

If one looks at the life story of every family having a Thalassaemia Major child, there is a clear similarity. Both parents are healthy individuals and have had a normal transition from childhood to adulthood. They go through the natural process of marriage and giving birth to a child. The child is diagnosed to be a Thalassaemia Major between 3 to 6 months of age. The Doctor tells them that the child will need lifelong blood transfusions for survival, which comes as a rude shock to them. They are then told that the child is a Thalassaemia Major only because both of them are Thalassaemia Minor.

Thalassaemia Minors are normal, healthy individuals. In most cases they do not know that they are Thalassaemia Minor. In India, there are an estimated 40 million persons who are Thalassaemia Minor. It is important for every youngster to do a blood test for Thalassaemia Minor. Knowing that one is a Thalassaemia Minor could be the most important revelation of one’s life.


What is Thalassaemia Major?

Thalassaemia Major is a serious, genetic blood disorder, which is characterized by the inability to produce appropriate haemoglobin, leading to premature of Red Blood Cells. As a consequence oxygen does not get carried to the tissues and cells of the body, leading to fatal consequences. Lifelong blood transfusions are required for survival.


Thal. Minor is a genetic status

Every physical characteristic and function of the human body is controlled by a pair of genes. Genes are present in every cell of our body. You have two of every kind of gene, one passed on by your mother, the other passed on by your father. One of these two genes tends to dominate and the other is recessive. The characteristic/function acquired by a person depends on which parent’s gene dominates. There could be some characteristic where the mother’s gene dominates, whereas in other characteristics the father’s gene may. Among many other pairs of genes, you have two genes that control how haemoglobin is made in each of your red blood cells.

  1. ‘Normal’ people are normal because they have two normal genes for haemoglobin. In other words, both parents have passed on normal genes for haemoglobin.
  2. Persons with Thalassaemia Minor (also called ‘carriers’) have one normal gene and one altered gene for haemoglobin. They are healthy because the normal gene becomes the dominant gene. One of the parents has passed on the altered gene. Therefore, atleast one parent is definitely a Thalassaemia Minor.
  3. People with Thalassaemia Major have two altered genes for haemoglobin. This means that both parents have passed on the altered gene. Therefore both parents have to be Thalassaemia Minor.

If one parent is Thalassaemia Minor and the other is Normal

If one parent in a marriage is a Thalassaemia Minor and the other is ‘Normal’:

  1. The gene that comes to the child from the Normal parent will always be the ‘normal’ gene.
  2. Tthe gene that comes from the parent who is Thalassaemia Minor could either be the ‘altered’ one or the ‘normal’ one.

There is 50% chance that the child will be ‘Normal’ and a 50% chance that the child will be a Thalassaemia Minor. In both cases the child can be expected to lead a normal healthy life.


If both parents are Thalassaemia Minor

If both partners in a marriage are Thalassaemia Minor, there are the following possibilities:

  1. Both mother and father pass on the normal gene – child is ‘normal’.
  2. Mother passes on the normal gene and father passes on the altered gene – child is a Thalassaemia Minor.
  3. Mother passes on the altered gene and father passes on the normal gene – child is a Thalassaemia Minor.
  4. Both mother and father pass on the altered gene – child is Thalassaemia major (serious problem).

Thus a Thalassaemia Major child is born only if both the mother and the father are Thalassaemia Minor.


Every healthy youngster must

  • Every healthy youngster must do a blood test for Thalassaemia Minor
  • If one is a Thalassaemia Minor one must get the spouse/future spouse also tested.
  • If both partners in a marriage are Thalassaemia Minor, there is a 25% chance in every pregnancy that their child will be a Thalassaemia Major.
  • If both partners are Thalassaemia Minor and desire a child, a Pre Natal Test very early in the pregnancy will determine if the foetus is affected or not.



  • There is nothing wrong in being a Thalassaemia Minor. There is everything wrong if you do not know that you are one.
  • You can never become a Thalassaemia Minor if you are not one from birth. The test needs to be done only once in your lifetime.
  • A single test once in your lifetime can save your child a lifetime of challenge.
  • Most people come to know that they are Thalassaemia only after the birth of their Thalassaemia Major child.