Beta-thalassaemia is a genetic blood disorder. A person who carries the beta-thalassaemia gene can appear perfectly healthy. However, where both partners carry the gene, there is a 1 in 4 chance that their child could inherit both their genes and develop beta-thalassaemia major.
The majority of infants with beta-thalassaemia will not have symptoms until they reach six months, because they start off with a different type of haemoglobin called fetal haemoglobin. After the age of six months, normal haemoglobin starts replacing the fetal one.