Rett syndrome : MECP2 Sequencing

Test Information

MECP2 sequencing is a molecular test used to identify variants in the gene associated with Rett syndrome.

Turnaround Time

3 weeks

CPT Code(s)






Clinical Information

A neurodevelopmental disorder that affects females, Rett syndrome is associated with cortical atrophy, stereotypical hand movements and severe intellectual disability. With an incidence of 1 in 10,000 - 15,000, it is one of the most common causes of intellectual disability in females. Rett syndrome is characterized by loss of acquired skills after a period of normal development in infancy. Most cases of Rett syndrome are caused by an abnormality (missense mutation, nonsense mutation or deletion) of MECP2.

Additionally, a specific phenotype has been identified in males with a MECP2 duplication that is identifiable by MLPA. These males display hypotonia that progresses to spasticity, severe intellectual disability and recurrent pulmonary infections. Females in these families who have the duplication are clinically unaffected and display a near total skewing of X-inactivation.

Sequencing of the MECP2 gene and MLPA deletion/duplication analysis can be ordered concurrently, sequentially or separately.


Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis.


Sanger Sequencing


Sequencing of the MECP2 gene will detect mutations in approximately 80% of individuals with Rett syndrome. Of those with a normal sequencing result, approximately 15% will have a deletion or duplication identified by MLPA.

Specimen Requirements

5 to 7 ml of peripheral blood collected in an EDTA (lavender top) tube is the preferred specimen type. The minimal blood needed for reliable DNA isolation is 3 ml. Extracted DNA, dried blood spots, and saliva are also accepted for this test.

Transport Instructions

The specimen should be kept at room temperature and delivered via overnight shipping. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.

Prenatal Testing Information

Prenatal diagnosis is available if the familial mutations are known. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.

Have Questions Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Kellie Walden, MS, CGC

Molecular Testing, Sanger Sequencing
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Meet The Jones Family

The journey to becoming parents did not start as an easy one for my husband and I. We suffered the heartache of miscarriage and the unimaginable pain of burying our first born child. Our son, sweet 1 lb 1.4 ounce, 12 inches long, teeny, tiny little Joseph “Hamilton” Jones was born with spina bifida, hydrocephalus, and a heart defect. It tore our hearts out leaving the hospital without him, knowing our dreams and hope for the future were shattered. ...

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