ARUP's Laboratory Test Directory

Rett Syndrome (MECP2), Sequencing and Deletion/Duplication : 0051614
[ image for: Patient History for Rett Syndrome (MECP2) or CDKL5-Related Disorders (CDKL5) Testing]
Patient History for Rett Syndrome (MECP2) or CDKL5-Related Disorders (CDKL5) Testing
[ image for: Additional Technical Information]
Additional Technical Information


Mnemonic: RETT FGA

Ordering Recommendation: Consultation with genetic counselor is recommended to plan the optimal MECP2 genetic testing sequence.
Methodology: Sequencing/Multiplex Ligation-dependent Probe Amplification
Performed: Varies
Reported: Within 21 days
Specimen Required: Collect: Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation: Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature: Refrigerated.

Stability (collection to initiation of testing): Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Reference Interval:
Test Number Components Reference Interval
0051618Rett Syndrome (MECP2), Deletion and Duplication By report
0051378Rett Syndrome (MECP2), Full Gene Sequencing By report

Interpretive Data: Background Information
Characteristics: 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.
Incidence: 1 in 10,000.
Inheritance: X-linked dominant; most cases are sporadic.
Cause: Methyl-CpG-Binding Protein 2 (MECP2) gene mutations.
Clinical Sensitivity: Up to 95 percent.
Methodology: bidirectional sequencing of the entire coding region and intron-exon boundaries; Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large MECP2 deletions /duplications; oligonucleotide probes cover all MECP2 in the coding region.
Analytical Sensitivity: 99 percent for sequencing and 90 percent for MLPA.
Analytic Specificity: 99 percent for sequencing and 98 percent for MLPA.
Limitations: Breakpoints of large deletions/duplications cannot be determined; deep intronic mutations will not be detected; analytical sensitivity may be compromised by rare primer site mutations.



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

See Compliance Statement C: www.aruplab.com/CS
CPT Code(s): 81302, 81304