May be useful for individuals with early-onset seizures and intellectual disability when MECP2 full-gene analysis fails to detect a pathogenic variant.
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 2 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Vary widely but may include early onset intractable seizures, severe developmental delay, with females often exhibiting features of Rett syndrome.
Incidence: Unknown; more frequent in females than males.
Inheritance: X-linked dominant; reported cases are de novo.
Penetrance: 100 percent.
Cause: Pathogenic CDKL5 gene mutations.
Clinical Sensitivity: Approximately 17 percent in females with infantile spasms or seizures.
Methodology: Bidirectional sequencing of theCDKL5 coding region and intron-exon boundaries. Multiplex ligation-dependent probe amplification (MLPA) to detect large CDKL5 coding regiondeletions/duplications.
Analytical Sensitivity and Specificity of Sequencing and MLPA: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations and deep intronic mutations will not be detected. The breakpoints of large deletions/duplications will not be determined.
|Component Test Code*||Component Chart Name||LOINC|
|2004936||CDKL5-Related Disorder Seq,DelDup Spec|
|2004937||CDKL5-Related Disorder Seq,DelDup Interp|
- Atypical Rett
- Epileptic Encephalopathy, Early Infantile 2
- Infantile Spasms/Atypical Rett
- Rett-Like Syndrome