Rett Syndrome (MECP2), Sequencing and Deletion/Duplication
Ordering Recommendation

Confirm clinical diagnosis of Rett syndrome or MECP2-related disorder. Consultation with a genetic counselor is recommended to plan the optimal MECP2 genetic testing sequence. ARUP's genetic counselors are available at 800-242-2787 x2141.

Sequencing/Multiplex Ligation-dependent Probe Amplification
14-21 days
New York DOH Approval Status
This test is New York DOH approved.
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B). 
Specimen Preparation
Transport 3 mL whole blood. (Min: 1 mL) 
Storage/Transport Temperature
Unacceptable Conditions
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable 
Reference Interval
Test Number
Reference Interval
0051618Rett Syndrome (MECP2), Deletion and DuplicationBy report
0051378Rett Syndrome (MECP2), Full Gene SequencingBy report

Interpretive Data
Background Information
Classic Rett Syndrome is a progressive neurodevelopmental disorder characterized by normal development until 6-18 months of age followed by rapid developmental regression, deceleration of head growth, loss of speech and acquired motor skills, and seizures; purposeful use of the hands is replaced by repetitive stereotyped hand movements. MECP2-related disorders include Rett-like Syndrome, severe congenital encephalopathy, or mild to severe mental retardation.
1 in 10,000.
X-linked dominant; most cases are sporadic.
Methyl-CpG-Binding Protein 2 (MECP2) gene mutations.
Clinical Sensitivity:
Up to 95 percent.
Bidirectional sequencing of the MECP2 coding regions (exons 1-4) and intron-exon boundaries; Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large deletions/duplications in the MECP2 coding regions (exons 1-4).
Analytical Sensitivity: 99 percent for sequencing and 90 percent for MLPA.
Analytic Specificity:
99 percent for sequencing and 98 percent for MLPA.
Breakpoints of large deletions/duplications cannot be determined; deep intronic mutations will not be detected.Diagnostic errors can occur due to rare sequence variations.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online at

Compliance Statement C: The performance characteristics of this test were validated by ARUP Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test. However, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. ARUP is authorized under Clinical Laboratory Improvement Amendments (CLIA) and by all states to perform high-complexity testing. Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Component Test Code*Component Chart NameLOINC
0051613Rett Syndrome (MECP2) Seq, DelDup Int
2001374Rett Syndrome (MECP2) Seq, DelDup Spcm
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
  • MECP2 sequencing and deletion/duplication assay