Women with G6PD Deficiency

Women with G6PD Deficiency are the most affected by myths and generally do not know they have G6PDD until a child is born and found to be G6PDD. The reason for this is that most G6PDD tests return not deficient for women with one affected X chromosome.

More men are G6PDD than women

First of all, this is statistically improbable, since men can ONLY inherit G6PDD from their mothers and women can get it from either or both parents. The actual statistics show that slightly more women than men have G6PDD5.

Women who have G6PDD are asymptomatic

This was proven wrong by two different research teams working independently30,59. Here’s how it works.

Women who have G6PDD come in two categories. Either with one or both X chromosomes affected. If both are affected, they are considered fully deficient and have symptoms like men. The other group with only one affected X chromosome (sometimes referred to as partially deficient or erroneously as carriers) vary in severity from mild to severe based on something called Lyonization30.


Lyonization is a process of selecting which X chromosome will be deactivated in a cell. It is a random process and happens early in an embryo’s life. Each cell chooses an X chromosome to deactivate and passes this choice to its progeny30. How many choose to deactivate the X chromosome affected by G6PDD determines how deficient the woman will be.

Let’s look at it in a simpler way. If half of the red blood cells have the good X chromosome deactivated, then half of her red blood cells will be fully deficient and half will be unaffected. When she comes into contact with a trigger, half of the blood cells will react and half will not. This ratio is completely random and can vary from only a small portion of red blood cells affected to most of them affected30,31,32. The resulting hemolysis from triggers will be small to large respectively. An indepth article explaining X inactivation and how it works can be found at59.

So, women are affected by triggers, but how much depends on the results of Lyonization.

Do women need to avoid triggers?

Yes. They should avoid triggers just like men. Even though the resulting hemolysis is, as a rule, less than that of a fully deficient woman or a man, any hemolysis over time can lead to other health problems. Lower levels of hemolysis can also cause other illnesses to be more severe. Unfortunately, lower levels of hemolysis are difficult to detect, which contributes to the myth that women are unaffected.

For more information, see Low Level Hemolysis.

Women with G6PD Deficiency was last modified: May 6th, 2019 by Dale Baker