Rare Disease affects only boys!
X Linked Androgen Resistance Syndrome causes males to have female characteristics.
Between 2 to 5 new parents out of each 100,000 will have a child with ARS. Most with have Complete Androgen Insensitivity Syndrome (CAIS) while a smaller number will have Partial Androgen Insensitivity Syndrome (PAIS). An even smaller number will be born with Mild Androgen Insensitivity Syndrome (MAIS).
In one of the northern European nations a study showed an instance of 1 case in 90,000 live births. As many cases are not detected until the child is in puberty there may not be a difference in incidence. There is generally no difference in incidence due to any demographic such as race that has been studied thus far.
For those parents with CAIS children, their new baby girl is genetically a boy. Their child looks like a girl and will probably continue to seem a perfectly normal girl until the child hits puberty.
If the child has PAIS it will most likely looks like a normal boy and genetically it is with a twist. When this child reaches puberty it will start developing in ways similar to a female even though it is genetically a male.
If the child has MAIS the child may look like either a boy or girl at birth but will most likely suffer some of the development issues of the other children at or following puberty.
All of these children are genetically males. All of these children are going to need a lot of help and support from their parents so that they can live as normal a life as possible.
CAIS children are usually detected earlier as the existence of testes is often found when there is a mass found during a childhood examination. When the doctor goes to remove the mass they find that the mass is actually the child’s testes.
PAIS children show symptoms of the disease when they reach puberty and instead of the usual male things they start growing breasts.
Now that the disease is better known it may be possible to detect it at birth. Children who are detected at birth will still face some potential for surgery in the future. If known at birth the child can have support and medications that will permit them to lead a nearly normal life. It is unlikely that they can ever have children, but except for confusing their sexual situation there is no barrier to a long and active life.
How does this happen?
Sex of humans used to be thought of as depending exclusively as how we looked. If you grow up with a penis and large biceps you were a man and if you grew up with large breasts and a vagina you were a woman.
It turns out that things are quite what they seem. They are certainly not as simple as a people’s physical appearance or their facial hair. Now that we can test DNA, we know that people with XY chromosome should be males and people with XX chromosome should develop into females.
ARS turns this on its head for a small group of males who are born with an XY chromosome and a mutated AR gene. It appears that this gene is responsible for creating resistance in the cells to using Androgen hence the name Androgen Resistance. The importance of this gene, that is apparently carried on the X chromosome, is that develop into a male boys need to be able to use androgen during puberty.
ARS is caused by mutations that occur in a whole variety of ways. If they happened in the distant past, they can be carried by female family members into a future generation. The gene is carried in a way similar to the eye color gene. Because most males who get the X gene for ARS are infertile, this is primarily a female condition.
Because the disease is caused by a mutation to the AR gene it can happen even if no parent has the defective gene. It can even happen in the fertilized egg.
Female children of parents where one parent is a carrier will not have the disease but may be a carrier for the disease in their own children should they have a male child.
DNA testing now allows the condition to be detected and the risk level to be determined. The fact that one male child has the disease does not increase or lower the risk of a second male child having the disease.
A female with two AR genes will pass it on to all male offspring while a female with one AR gene has a much lower risk of passing the gene on.
American parents that have a child with this disease can find help by contacting one of the support groups listed in the links section of this article.
The most important thing that parents can do for their child is to make sure they have an opportunity to grow up and live as normal a life as possible. In most cases their child will need some surgery as a result of this condition. The support groups can be of particular help to the parents in determining a strategy to best help their child and take care of their needs as parents.
Androgen Insensitivity Syndrome Support Group (AISSG) is listed in the links.
As with any disease it is best to consult with a knowledgeable doctor if you think a disease affects you or your child.
