3 deletions in alpha 2 -Thalassemia- Dr. Sattar's lecture

[shigella123]

It is said that normal Hb are

1- Fetal Hb A= alpha 2 and gamma 2
2- Hb A = alpha 2 beta 2
3- HB A2= alpha 2 and delta 2

So when Dr. Sattar says there are 3 genes deleted in alpha thal, child is ok until he grows up and starts producing adult HB cuz Fetal Hb only needs 1 alpha 2 and gamma 2, but my question is in adult Hb we also have 1 alpha 2 and 1 beta 2 so why is that not ok?

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[addy]

IDK how scientifically correct this is, but the way I think of it is this--

When you have 3 deletions and its time to make HbA, the 3 deletions with regards to alpha production do not allow you to keep up with the pace of beta production. That's why you have HbH (beta aggregates) in 3 deletions. When you're an infant, you can make it in fast enough pace so excess gamma isn't a problem.

 

[shigella123]

Thanks for responding Addy. It kinda makes sense.