Table 1 Common alpha thalassaemia molecular disorders

• Deletion at a single α-globin gene

-α or –α

-α^3.7, −α^4.2, (α)^20.5 etc.

• Absence of α-globin genes on one chromosome

–

--^{MED I}, −-^{MED II}, −-^SEA, −-^SPAN, −-^FIL, −-^THAI,

• Mutations that affect the upstream regulatory elements

(αα)^T

(αα)^RA, (αα)^ALT, (αα)^JX

• Non-deletional mutations

α^Tα, αα^T or α^Tα^T

α^CSα, α^QSα, α^ADANAα, α ^IVS1(−5nt) α