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Laboratory Test Directory

SHOC2 Gene Sequencing

Components

Name Method Department Units
SHOC2 Gene Sequencing Analysis of the entire coding region: Sequence analysis
Polymerase chain reaction (PCR)
Sanger sequencing
DNA extraction
Molecular Genetics

Specimen Requirements

Whole blood

Container Type Container Size Specimen Volume
Preferred

Purple tube (EDTA)

4 mL 4 mL-8 mL
Stability

Room temperature - 24 hour(s)
Refrigerated - 72 hour(s)

Specimen Preparation

  • Do not centrifuge
  • Do not freeze

Reasons for Rejection

  • Clotted specimen
  • Centrifuged specimen
  • Frozen specimen
  • Wrong collection tube
  • Delayed or improper handling

Comments

Please click on the Lab Form Link in the Forms Section to print and complete the Genetic Test Requisition Form. Submission of completed Genetic Test Requisition Form is required, and submission of informed consent form is recommended.

This test is a full gene sequencing of the SHOC2 gene, which is associated with a group of disorders called Noonan spectrum disorders (RASopathies). RASopathies include Noonan syndrome, Costello syndrome, cardio-facio-cutaneous (CFC) syndrome, and LEOPARD syndrome. They are related genetic disorders caused by mutations in the genes that encode proteins in RAS-mitogen-activated protein kinase (MAPK) signal transduction pathway. These four disorders have molecular and phenotypic overlap; however, each also has a distinct set of defining characteristics.

Noonan syndrome is caused by mutations in PTPN11 (50%), SOS1 (10%), KRAS (<5%), RAF1 (3%-17%) and NRAS and SHOC2 (each 1% or less). Costello syndrome is associated with mutations in HRAS (80%-90%). CFC syndrome is caused by mutations in BRAF (75%-80%), MAP2K1 (MEK1) and MAP2K2 (MEK2) (10%-15%), and KRAS (<5%). LEOPARD syndrome is caused by mutations in PTPN11 (90%) and RAF1 (<10%). It is likely that additional undefined genes, possibly related to RAS-MAPK signal transduction, are associated with these disorders. Thus, a negative result does NOT rule out any given clinical diagnosis. For comprehensive RASopathy genetic evaluation, NGS RASopathy Panel (Test Code: NGSRP) is recommended, which is a full gene sequencing panel for 14 genes associated with RASopathy disorders.

Forms

Lab Form

CPT Code

  • 81405