This is a second tier test and REQUIRES PERMISSION from ARUP's Genetic Counselor (800-242-2787, x2141) before ordering. Preferred initial test is the sequencing and deletion/duplication test.
- 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
- Always consult with Fragment Analysis technical supervisor (ext. 2320) or technical liaison (est. 4429).
Plasma, buccal brush or swab, FFPE tissue, fresh/frozen tissue.
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Cafe au lait spots, axillary and inguinal freckling, learning disabilities and macrocephaly. Neurofibromas, lisch nodules and CNS tumors are not observed.
Incidence: Unknown; may represent 0.5 percent of neurofibromatosis type 1 diagnoses or 8 percent of those with isolated cafe au lait spots.
Inheritance: Autosomal dominant.
Cause: Pathogenic SPRED1 gene mutations.
Clinical Sensitivity: Unknown.
Methodology: Multiplex ligation-dependent probe amplification (MLPA) to detect large SPRED1 locus and intragenicdeletions/duplications.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Breakpoints for large deletions/duplications will not be determined. SPRED1 base pair substitutions, small deletions/duplications, deep intronic, and regulatory region mutations will not be detected.
|Component Test Code*||Component Chart Name||LOINC|
|2008374||Legius Syndrome (SPRED1) DelDup Specimen|
|2008375||Legius Syndrome (SPRED1) DelDup Interp|
- SPRED1 deletion/duplication assay