B-Thalessemia Hello, Mr. And Mrs. Jones. You

B-Thalessemia

Hello, Mr. And Mrs. Jones.

You came to us because you each have relatives with B-thalessemia. You wanted to know what the chances were that you would have children with this disease.

The only way a baby can be born with B-thalessemia is if both parents carry the gene for it. At conception, each child receives one set of genes from each parent. Because each of you received one gene for B-thalessemia, it is possible that your children could inherit this disease. Neither of you are sick from it because you have "Thalassemia minor" -- one gene. However, each time you conceive a child, there's a one in four chance that the child will inherit a B-thalessemia gene from each of you. That child would have thalessemia major, a potentially serious form of the disease. In this disease, there are changes in the hemoglobin of the red blood cells. The cells can't carry oxygen efficiently throughout the body, and that can cause various problems.

Thalessemia minor was a beneficial condition for many centuries because people like it -- people like each of you -- were less likely to catch Malaria. So, people with Thalessemia minor were more likely to survive and reproduce. When their children inherited only one gene, they had Thalessimia minor, like their parents, and were also likely to get Malaria. However, if the child inherited a B-thalssemia gene from both parents, then the child had Thalessemia major.

Because each of you carry one B-Thalessemia gene, every time you conceive a child, that child has a one in four chance of receiving two genes, and having Thalessemia major. This means there is a three out of four chance the child will not have Thalessemia major, and a one in four chance that the child will not receive any Thalessemia genes. If only one parent carries the gene, the children cannot develop the more serious form of Thalessemia.

Even when a child has Thalessemia major, the amount of severity depends on the exact genes inherited, because there are several gene variations that can cause Thalessemia.

If your child inherits one gene, he or she may tend to be a little anemic, but many people have one gene for it and don't even know it. Very often having one gene doesn't require any special medical care. But if a child inherits a Thalessemia gene from each parent, that child faces significant health problems. Any child who inherits one Thalessemia gene should get genetic counseling when he or she marries, because the gene is fairly common. The couple will need to know whether their children might inherit two genes. To know that, your child's spouse will have to be tested to see if he or she also carries the gene. This is why a person with one gene is called a "carrier." Both of you are carriers, so you can have children with Thalessemia major.