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)

81302

Cost

$900

Genes

Disorders

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.

Indications

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.

Methodology

Sanger Sequencing

Detection

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

The preferred sample type is peripheral blood collected in an EDTA (purple top) tube – at least 2-3ml for pediatric patients and 5-6ml for adult patients. Extracted DNA, dried blood spots, and saliva are also accepted for this test. Saliva samples must be submitted in an approved saliva kit. Contact the lab to receive a saliva kit or to have one sent to your patient.

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
Lucy's Story

Lucy's Story

When our daughter Lucy had a metabolic crisis at 7 days old, we were shocked and devastated to find out that she was born with a rare genetic disorder (MSUD). Her newborn screening results did not make it back in time to prevent the crisis, and no one at our local hospital was familiar with the disease. They did not know how to treat her. Calls were made to Greenwood Genetic Center to confirm her diagnosis...

In The News