What is it?
Rett Syndrome only affects girls, and is a neurological development disorder that is the main cause for mental retardation. Since males only have one X chromosome, they don't have another chromosome to compensate for a defect, meaning if they had a defected X chromosome it would probably end in a miscarriage or early death.
Why is it considered X-Linked dominant?
This means that the gene of interest on the X chromosome is dominant. The X chromosome is a sex chromosome meaning (among other things) it is inherited differently between men and women. Women normally receive two X chromosomes. As this is a dominant trait it would mean that a woman would need to inherit the defective gene on only one chromosome one from her mother or from her father to display the trait. It should also be noted that the offspring can be affected only if one of the parents is affected as is true for any dominant trait. As males only receive one X chromosome (from the mother the other a Y from the father) they only need to inherit the trait once for it to be displayed. This makes the characteristics of the trait or disease apparent more often in male offspring and the females are usually the carriers.
What are the symptoms?
From the ages of 6-18 months the little girl may seem completely normal, but soon after her brain functions will start to deteriorate and between the ages of 1 and 2 she will lose her speech, have symptoms of autism, have a very small head, hyperventilate and have dementia.
After some time, it may seem like she has started to stabilize when suddenly she will start to have seizures and her growth will slow down and she will be a very short person.
What treatments are available?
Although there is no cure for Rett Syndrome, there are treatments that can help those that suffer from it. Medications, will help control seizures and muscle stiffness that comes with this syndrome. Physical and speech therapy can also help with scoliosis, walking skills, balance and flexibility. Speech therapy can help the child to learn nonverbal ways to speak (Mayo Clinic). 