Noonan Syndrome - Tiered Molecular
Testing
Noonan syndrome is
characterized by short stature, developmental delay, characteristic facial
features, a webbed or broad neck, low-set nipples and chest abnormalities. Heart
defects are present in up to 80% of patients and mild mental retardation may be
a feature in approximately 1/3 of patients.
Noonan syndrome can be
caused by a mutation in one of four known genes. The Molecular Diagnostic
Laboratory of the Greenwood Genetic Center is offering a tiered approach to the
molecular diagnosis of Noonan syndrome. PTPN11 mutations are responsible
for approximately 50% of Noonan syndrome cases. Mutations in SOS1 have
been identified in approximately 15-20% of those without a PTPN11 mutation.
RAF1 and KRAS are each responsible for approximately 5% of
individuals with Noonan syndrome .
-
Tier 1: Full sequencing
of PTPN11
-
Tier 2: Full sequencing
of SOS1
-
Tier 3: Full sequencing
of RAF1 and KRAS
These tiers may be ordered
separately or can be run simultaneously.
The features of Noonan
syndrome are often found to overlap with those of
Costello syndrome
and
cardio-facio-cutaneous (CFC) syndrome. Tiered analyses for each
of those conditions is also available from the Greenwood Genetic Center.
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.
If necessary, ACD solution A Vacutainer tubes (yellow top) may be submitted.
Please contact the laboratory for more information.
Transport:
Please contact the Molecular Diagnostic Lab Coordinator (1-800-473-9411) for
shipping information. 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.
Analysis standards:
Analysis will be complete within 6 weeks of sample receipt. The laboratory
director and technical staff members independently assess the quality and
interpretation of the test. The Greenwood Genetic Center Molecular Diagnostic
Laboratory is CLIA certified and actively participates in CAP proficiency
surveys.
Reporting of Test
Results: Test results with
interpretation will be mailed and/or faxed following completion of the test.
Verbal reports will be telephoned to the person(s) requesting the test when an
abnormal test result occurs. Consultation with the laboratory director and
explanations of testing protocols are available upon request.
CPT Codes:
-
Tier 1: 83890, 83898
(x5), 83904 (x4), 83909 (x4), 83912
-
Tier 2: 83890, 83898
(x11), 83904 (x8), 83909 (x8), 83912
-
Tier 3: 83890, 83898
(x5), 83904 (x4), 83909 (x4), 83912
-
Panel (Tier 1, 2 and 3 run simultaneously):
83890, 83898 (x20), 83904 (x19), 83909 (x19), 83912
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