Connect Sign In
Fragile X ( FMR1 ) with Reflex to Methylation Analysis, Fetal
Ordering Recommendation
Prenatal test for fetuses of mothers with fragile X premutations or full mutations.
Maternal cell contamination (MCC) analysis is required and performed at no additional charge. Order Maternal Cell Contamination, Maternal Specimen (0050608) on a maternal blood specimen.
For guidance on ordering maternal cell contamination studies, please refer to Maternal Cell Contamination (MCC) Analysis Guide.
New York DOH Approval Status
Specimen Required
Fetal Specimen: Cultured amniocytes.
Maternal Specimen: Refer to Maternal Cell Contamination, Maternal Specimen (0050608) for maternal specimen requirements.
Transport: Two T-25 flasks of 80% confluent cultured amniocytes. Cultured amniocytes are required for testing. If submitting uncultured (direct) amniotic fluid and testing is desired on a cultured specimen, add Cell Culture for Genetic Testing (3020627). If transporting flasks, the client is responsible for maintaining backup cultures at the client institution. If ARUP receives cultured fetal cells below minimum confluence, Cell Culture for Genetic Testing (3020627) will be added by ARUP.
Preferred transport: Room temperature.
Preferred shipment: Within two days of collection or confluence.
Frozen specimens.
Methylation patterns may not be fully established in early gestation; thus, methylation testing performed on chorionic villus samples may not distinguish between premutation and full mutation alleles.
Counseling and informed consent are recommended for genetic testing. Consent forms are linked above.
New York Clients: informed consent is required with submission.
Room temperature: 2 days; Refrigerated: Unacceptable; Frozen: Unacceptable
Methodology
Polymerase Chain Reaction (PCR) / Capillary Electrophoresis
Performed
Varies
Reported
9-10 days
If culture is required, an additional 1 to 2 weeks is required for processing time.
Reference Interval
Refer to report
Interpretive Data
Refer to report.
| Phenotype | Number of CGG Repeats |
|---|---|
| Unaffected | < 45 |
| Intermediate | 45-54 |
| Premutation | 55-200 |
| Affected | >200 |
Laboratory Developed Test (LDT)
Note
If a CGG repeat of 100 or greater is detected by PCR and capillary electrophoresis, methylation analysis will be added. Additional charges apply.
Hotline History
Hotline History
CPT Codes
81243; 81265 Fetal Cell Contamination (FCC); if reflexed, add 81244
Components
| Component Test Code* | Component Chart Name | LOINC |
|---|---|---|
| 0050548 | Maternal Contamination Study Fetal Spec | 59266-7 |
| 0050556 | Fragile X Allele 1 | 45321-7 |
| 0050558 | Fragile X Allele 2 | 45322-5 |
| 0050559 | Fragile X Methylation Pattern | 41107-4 |
| 0050612 | Maternal Contam Study, Maternal Spec | 66746-9 |
| 0051389 | Fragile X Fetal Specimen | 66746-9 |
| 2010041 | Fragile X Interpretation, Fetal | 36914-0 |
Aliases
- Cytogenetics, High Resolution & Fragile X DNA (Fragile X (FMR1) Diagnostic, Fetal)
- High Resolution & Fragile X DNA (Fragile X (FMR1) Diagnostic, Fetal)
- Inherited Mental Retardation (Fragile X (FMR1) Diagnostic, Fetal)
- Martin-Bell Syndrome (Fragile X (FMR1) Diagnostic, Fetal)
