A mutation in another gene on the X-chromosome known as CDKL5 ( Cyclin- Dependent Kinase -Like 5) can cause symptoms similar to the atypical form of Rett Syndrome, and the MECP2 mutation test is usually negative.
On the other hand, not everyone with a CDKL5 mutation shows symptoms of Atypical Rett Syndrome.
For more information, visit http://www.cdkl5.com/ You can visit the website.
Mutations in the FOXG1 gene on chromosome 14 may be responsible for a congenital variant of Rett Syndrome, and tests for a MECP2 mutation often come back negative.
Everyone with a FOXG1 mutation will develop Atypical Rett Syndrome.
For more information, visit http://foxg1.com/ You can visit the website.
Mutations in another gene on the X chromosome, known as WDR45, which is known to be associated with BPAN Syndrome, have recently been found in several girls diagnosed with Rett Syndrome who were not MECP2 mutation positive.
For more information about this gene screening, please download the brochure from this address.
How will the genetic test be performed?
Complete sequencing of MECP2 exons 1-4 and , if the result is negative, duplication / deletion analysis .”
Can any laboratory perform a complete MECP2 test?
No. Consider that some labs only perform sequencing of 2-4 exons , some can only look for specific point mutations, and some cannot perform duplication/ deletion analysis ( i.e., cannot perform a “full” test). Make sure they can perform the “Full Test” before you collect blood for testing.
Will my insurance cover the test costs? How much does the test cost?
Private health insurance does not cover MECP2 test costs. The Social Security Institution (SGK) only covers the cost of tests performed at laboratories contracted with SGK, on a “one-time” basis. Since fees vary greatly among private laboratories, obtaining price quotes from multiple laboratories before the test is the best approach.
My daughter’s test result was negative, do we need to get another test done?
Duplication / deletion analysis can only be performed if a complete sequencing of MECP2 exons 1-4 has been requested by your doctor and the result is negative .
The MECP2 test was completely negative. Are there any other blood tests that need to be done? Is that all?
The MECP2 sequencing and duplication / deletion test results are negative and you are certain that a full test has been performed, discuss with your daughter’s doctor whether other tests, such as CDKL5 and FOXG1, should be performed. The decision to test these will be made by your doctor based on her clinical history and presentation.
Source: International Rett Syndrome Association – www.rettsyndrome.org