MECP2-Related Disorders
Rett syndrome and its variants: MECP2-related severe neonatal encephalopathy and X-linked mental retardation
About the Disorder | Indications | Specimen l Testing Methodology l Sensitivity l Turnaround Time l Cost l CPT Codes l Shipping l Results l Contact Us
Mutations in MECP2 result in broad phenotypic variability. In females, MECP2 mutations may present as classic Rett syndrome characterized by a period of normal development followed by rapid regression of language and motor skills by two years of age. Atypical variants of Rett syndrome have also been described in individuals with MECP2 mutations including mental retardation and autism spectrum disorders. Finally, mutations in MECP2 have been identified in intellectually normal and mildly impaired women, presumably due to non-random X-inactivation.
In males, MECP2 mutations classically present with severe neonatal encephalopathy with early lethality. A few males have been reported with typical Rett syndrome and MECP2 mutations. Mutations in MECP2 have also been described in association with X-linked mental retardation (PPMX) in some families.
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- Diagnostic testing in females with suspected Rett syndrome or variant
- Diagnostic testing in males with severe neonatal encephalopathy
- Diagnostic testing in selected individuals who had defied characterization including some patients with autism, Angelman syndrome and intellectual disability, among others
- Prenatal diagnosis in families with an identified MECP2 mutation (by previous arrangement only)
- Cadeleterrier testing in relative of a patient with a MECP2-related disorder
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At least 3mL whole blood in purpletop (EDTA) tube. Label tube with patient's name, birth date, and date of collection. Buccal swabs are required for analysis in patients who have undergone transplantation and may facilitate DNA isolation in patients undergoing chemotherapy or in individuals with leukopenia. Please call for a free buccal swab collection kit.
PCR-based sequencing of the entire coding region and intron/exon boundaries of the FAS (TNFRSF6) gene.
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PCR-based sequencing of the coding regions and their exon/intron boundaries of the MECP2 gene detects ~ 80% patients with classic Rett syndrome. Multiple exon deletions are identified in approximately 15-20% of patients and can be identified by multiplex ligation (MLPA). Mutations in CDKL5 are also associated with Rett syndrome in a small minority of affected individuals. Both tests are clinically available. Approximately 75% of patients with ALPS have a mutation in FAS. PCR-based sequencing detects the majority of mutations in the FAS gene. Gross deletions and rearrangements are present in less than 10% of patients with ALPS and are not detected with this methodology. Similarly, somatic mutations in double negative T cells have been reported in some patients with ALPS and are not detected with this test.
The sensitivity of PCR-based DNA sequencing is over 99% for the detection of nucleotide base changes, small deletions and insertions in the regions analyzed. Mutations in regulatory regions or other untranslated regions are not detected by this test. Multiple exon deletions, large insertions, genetic recombinational events and rare, primer site mutations are not be identified by this methodology.
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3-4 weeks
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Please call 866-450-4198 for current pricing, billing information or for test preauthorization.
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- MECP2 sequence analysis: 83890, 83898(x6), 83894(x6), 83891(x5), 83904(x10), 83909(x10), 83912
Family specific analysis: 83890, 83898, 83894, 83891, 83904, 83912
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Please enclose test requisition with sample. All information must be completed before sample can be processed. Place samples in Styrofoam mailer and ship at room temperature by overnight Federal Express to arrive Monday through Friday.
Ship to
Cytogenetics and Molecular Genetics Laboratories
3333 Burnet Avenue NRB 1042
Cincinnati, OH 45229
Phone 513-636-4474
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Each test report includes a detailed interpretation of the genetic findings, the clinical significance of the result, and specific recommendations for clinical management and additional testing, if warranted. Results will be reported to the referring physician or health care provider as specified on the test requisition form.
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For additional inquiries, contact us:
Phone 513-636-4474
Fax 513-636-4373
Email moleculargenetics@cchmc.org
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