Costello Syndrome – Tiered Molecular Testing


Disorder Costello syndrome
Gene Names Tier 1: HRAS – first coding exon (exon 2)
Tier 2: HRAS – remaining exons (exons 3-5) including both splice variants for exon 4
Full Panel: Tiers 1 and 2 (full sequencing of coding region, exons 2-5)
Clinical info Costello syndrome is characterized by intellectual disability, coarse facial features, feeding difficulties, failure to thrive, loose fold of skin (especially on the hands and feet), joint flexibility, short stature, cardiac anomalies and papilomas around the mouth, nose and perianal regions.
Indications Tiers may be ordered separately or can be run as a concurrent panel. If you are requesting multiple tiers, but would like each run separately, please indicate the order if which testing should be done. Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutation within a family to allow for carrier testing and prenatal diagnosis.
Associated Tests The features of Costello syndrome are often found to overlap with those of Noonan syndrome and Cardio-Facio-Cutaneous (CFC) syndrome. Tiered analyses for each of those conditions is also available. In addition, this gene is included in the NGS RASopathy Panel.
Detection Costello syndrome is caused by mutations within the HRAS gene with approximately 80-90% of mutations found in the first coding exon (often called exon 2 in the literature).
Specimen Requirements 5 to 10 ml of peripheral blood collected in an EDTA (lavender top) Vacutainer tube is preferred. The minimal blood needed for reliable DNA isolation is 3 ml
Transport The specimen should be kept at room temperature and delivered via overnight shipping. FedEx is preferred. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.
Turnaround time Tier 1: 2 weeks
Tier 2: 6 weeks
Prenatal testing Prenatal diagnosis is available if the familial mutation is known. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.
CPT Codes Unknown mutation
Tier 1: 81403
Tier 2: 81479
Full Panel (Tier 1 and 2 run simultaneously): 81404

Known mutation: 81403

Deletion/Duplication Analysis: 81405
Cost $300 for Tier 1
$400 for Tier 2
$700 for Full Panel

$350 for known mutation

$700 for deletion/duplication analysis

Prenatal diagnosis for known mutation is $1000.  Please contact the laboratory for more information.

Contact For further information contact one of our This email address is being protected from spambots. You need JavaScript enabled to view it. at 1-800-473-9411.

Molecular Diagnostic Lab

The Molecular Diagnostic Lab offers DNA analysis for many genetic disorders via gene sequencing, targeted mutation analysis, MLPA deletion/duplication testing, trinucleotide repeat analysis and next generation sequencing panels.

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