Abnormal Hemoglobin

My son was diagnosed with a abnormal hemoglobin called Koln when he was about 10 months.  His hemoglobin level was 4.7 when we went to the hospital.  He had two blood transfusions.  I haven't heard of this condition until now.  He is about 15 months now and he recently got sick.  Fortunately, he was able to get well on his own without the help of a blood tranfusion.  My husband and I are not sure if what our son has is hereditary if we want to have another child.  We would love to but we don't want another child to have to go through what our son has gone through.  Any help would be greatly appreciated.  Thanks in advance!

[Lisa Kessler, MS, CGC]

It sounds like you have gone through a great deal, but I am glad to hear
that your son was able to get well on his own this time. You are asking
very important questions. As you may have learned, hemoglobin Koln is the
most common form of unstable hemoglobin and is part of a group of conditions
known as hemolytic anemias. Hemolytic anemia occurs when the body destroys
red blood cells and removes them from the blood too soon. The breakdown of
red blood cells is called hemolysis. Anemia means not having enough red
blood cells in the blood or not having enough hemoglobin in the red blood
cells. Hemoglobin is responsible for carrying oxygen to the different parts
of the body.

There is a test that can be done to look for the genetic change which causes
Hb Koln. This condition often runs in families in an autosomal dominant
way. This means that if someone has the condition, then there is a 50%
chance of passing it on to each child. However, there have been some
reports of hemoglobin Koln in a child in whom the parents did not have the
gene change. In this case, the risk to have another child with hemoglobin
Koln is lower than 50%. In order to determine the chances that another
child of yours would have Hb Koln, it is important to meet with a genetic
counselor. S/he will discuss the testing options for your son, and for you
and your husband to determine if either of you may carry the gene change
that is associated with this condition. If one of you is found to carry the
gene change, the risk to have another child with Hb Koln is 50%. The
genetic counselor will also discuss all options for considering another
pregnancy including taking no action, prenatal diagnosis which can be used
to test for Hb Koln if there is a mutation previously identified in the
family, donor egg/sperm, or adoption. You can find a genetic counselor
through the National Society of Genetic Counselor's website.