Acceptable initial test to confirm a clinical diagnosis of Noonan syndrome or LEOPARD syndrome.
- 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
Characteristics of NS: Short stature, developmental delay, dysmorphic facial features, congenital heart disease, broad or webbed neck, superior pectus carinatum and inferior pectus excavatum, low-set nipples, cryptorchidism, coagulation, and lymphatic disorders.
Incidence: 1 in 1,000 to 1 in 2,500.
Inheritance: Autosomal dominant.
Cause of NS: Pathogenic mutations in PTPN11, SOS1, RAF1, KRAS and other unidentified genes.
Genes tested: PTPN11 and SOS1.
Clinical Sensitivity: Approximately 70 percent.
Methodology: Bidirectional sequencing of the entire PTPN11 coding region and intron-exon boundaries. If no known pathogenic mutations are detected, bidirectional sequencing of the SOS1 coding region and intron-exon boundaries is performed.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations, deep intronic mutations and large deletions/duplications will not be detected. Mutations in genes, other than PTPN11 and SOS1, will not be evaluated.
|Component Test Code*||Component Chart Name||LOINC|
|2004190||NS REFLEX Specimen|
|2004192||Noonan Syndrome Interpretation|
- PTPN11 and SOS1 reflex assay