Legius Syndrome (SPRED1) Sequencing
Ordering Recommendation

Acceptable diagnostic and predictive test for Legius syndrome for symptomatic individuals who test negative for NF1 gene variants.

Polymerase Chain Reaction/Sequencing
14-21 days
New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B). 
Specimen Preparation
Transport 3 mL whole blood. (Min: 1 mL) 
Storage/Transport Temperature
Unacceptable Conditions
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable 
Reference Interval
By report
Interpretive Data
Background Information for Legius Syndrome (SPRED1) Sequencing
Cafe au lait spots, axillary and inguinal freckling, learning disability 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.
Autosomal dominant.
Cause: Pathogenic SPRED1 gene mutations
Clinical Sensitivity: Unknown.
Methodology: Bidirectional sequencing of the entire SPRED1 coding region and intron-exon boundaries.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Some SPRED1 gene regulatory region mutations, deep intronic mutations, and large deletions/duplications will not be detected. Diagnostic errors can occur due to rare sequence variations.

Statement C: Compliance Statement C: For human genetic inheritable conditions and mutations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Hotline History
Component Test Code*Component Chart NameLOINC
2002946Legius Syndrome Specimen
2002947Legius Syndrome Sequencing Interp
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please view this test within the Laboratory Test Directory found at www.aruplab.com
  • NF1-Like Syndrome Sequencing and (NF1) Sequencing Exon 22 (Exon 17))
  • SPRED1 sequencing
  • SPRED1 Sequencing and (NF1) Sequencing Exon 22 (Exon 17))