In 2012, our laboratory introduced the next generation sequencing testing panel for Noonan syndrome, an important prenatal testing option for fetuses with increased nuchal translucency and normal karyotype. Based on our experience with over 500 patients at that time, we updated our testing options to provide the most clinically significant information as quickly and as cost effectively as possible. For this reason, we now offer Noonan syndrome and spinal muscular atrophy as prenatal testing options that may be ordered together or separately, at the discretion of the referring genetics provider.
We are also excited to announce our long-awaited next generation sequencing Skeletal Dysplasia Testing Panel, which may also be considered for fetuses with increased nuchal translucency and normal karyotype.
Noonan Syndrome
Noonan syndrome is an autosomal dominant condition with variable expressivity, characterized by short stature, congenital heart defect, and developmental delay of variable degree. Other findings include broad or webbed neck, unusual chest shape, cryptorchidism, characteristic facies, varied coagulation defects, lymphatic dysplasias, and ocular abnormalities.
Our current Noonan syndrome panel uses next generation sequencing to test for mutations in the five major genes known to be associated with Noonan syndrome, including PTPN11, KRAS, SOS1, RAF1, and MEK1, with a total detection of more than 70%.
Of the first 500 fetuses tested, just under 5% were found to have a mutation in one of these five genes associated with Noonan syndrome. We also recommend parental testing following an identified mutation in the fetal sample, as many fetuses were found to have paternally inherited mutations.
Spinal Muscular Atrophy
Spinal muscular atrophy (SMA) is an autosomal recessive condition characterized by progressive muscle weakness resulting from degeneration and loss of anterior horn cells in the spinal cord and brain stem nuclei. Onset ranges from before birth to adolescence or young adulthood. Poor weight gain, sleep difficulties, pneumonia, scoliosis, and joint contractures are common complications.
Our laboratory uses a standard PCR-based assay to determine the number of SMN1 gene copies, and is one of the only laboratories that also includes testing for 48 point mutations in SMN1, with a combined detection of approximately 96%.
Of the first 500 fetuses tested, more than 4% were found to be carriers for spinal muscular atrophy, while none were expected to be affected with the condition.
Billing Items:
All samples must include patient clinical information relevant to the testing being ordered. This information helps us to work with the patient's insurance provider when securing coverage. We also request a copy (front and back) of their insurance card if the patient is going through private insurance. In addition, we are now offering an institutional billing option as well as discounted patient pricing. For more information please contact our office.
CPT Codes:
Noonan syndrome testing panel: 81403x1, 81405x3, 81406x1
Spinal muscular atrophy: 81400, 81401, 81043
Maternal cell contamination studies: 81265
Specimen and Shipping Requirements:
For our next-generation sequencing testing panels, we are able to accept:
- Direct chorionic villi: 15-20mg
- 2 T-25 flasks of confluent fetal cells
- Extracted DNA: 3 micrograms in a minimum of 50 uL
Maternal cell contamination studies are also required prior to all next-generation sequencing tests; therefore a maternal blood sample is also required.
Unfortunately, we are unable to perform testing on direct amniotic fluid samples at this time, due to low concentration of DNA present in these samples.
Additional specimen must be held for back-up culture at another facility.
Please note: If the sample volume is less than requested, tissue culture will be required. This will delay the processing of genetic testing and no guarantees can be made if the sample fails to grow in culture. We will notify the referring physician/counselor/laboratory if the sample is inadequate.
Shipping Requirements
Ship overnight at ambient temperature to arrive Monday-Friday. A completed requisition form, billing form, and consent form must be included with the sample. Shipping costs are the responsibility of the sender.
Ship to: Insight Medical Genetics, 680 N. Lake Shore Drive, Suite 1230, Chicago, IL 60611 Telephone number: 312-981-4400
Turnaround Time: Approximately 3-4 weeks.