 Print View Attached Docs: |
|||||||||
| 91120:FRAGILE X DNA ANALYSIS | |||||||||
| Alias Names: | Frax A | ||||||||
| Methodology: | DNA Isolation | ||||||||
| Edit Date: | 11/8/2010 | ||||||||
| Performed: | Monday | ||||||||
| Released: | 2 weeks after setup at PeaceHealth Laboratories’ reference lab. | ||||||||
| CPT Code: | 83890-905B / 83896-905B / 83898-905B / 83909-905B / 83912-905B | ||||||||
| Specimen Collection Details | |||||||||
| Collection: | One 6 mL yellow top tube (ACD) Solution B, or one 8.5 yellow top tube (ACD) Solution A. Also acceptable: One 4 mL lavender top tube (EDTA). | ||||||||
| Handling: | Keep ambient. Do not centrifuge or separate. | ||||||||
| Standard Volume: | 5 mL whole blood. | ||||||||
| Minimum Volume: | 3 mL whole blood. | ||||||||
| Transport: | Ambient. | ||||||||
| Comments: | Testing is diagnostic for normal/carrier/disease states. Fragile X Syndrome is the most common hereditary cause of mental retardation. Testing is indicated in mentally retarded individuals and in individuals with a family history of mental retardation or learning disability of unknown etiology. | ||||||||
| Rejection Criteria: | Frozen specimen.
This test may require insurance company prior authorization before ordering.
Please check the prior authorization list . Failure to gain preauthorization may result in denial of coverage. |
||||||||
| Reference Range: | |||||||||||||||||||
| Measurement of CGG trinucleotide repeat number in exon 1 of the FMR-1 gene at Xq27.3.
Allele Types #CGG Repeats |
|||||||||||||||||||
| Normal | ~5 – ~44 | ||||||||||||||||||
| Intermediate | ~45 – ~54 | ||||||||||||||||||
| Premutation | ~55 – 200 | ||||||||||||||||||
| Full mutation (disease-causing) | >200 | ||||||||||||||||||
| Interpretation | |||||||||||||||||||
| 5-44 repeats | No clinical phenotype | ||||||||||||||||||
| 45-200 repeats | No clinical phenotype but genetic counseling recommended. | ||||||||||||||||||
| >200 repeats | Clinically affected males; females at risk for Fragile X syndrome. | ||||||||||||||||||