Beckwith-Wiedemann Syndrome (BWS): CDKN1C Sequencing

CDKN1C sequencing is a molecular test used to identify variants in the gene associated with Beckwith-Wiedemann Syndrome.

Turnaround Time

3 weeks

CPT Code(s)

81479

Cost

$500

Genes

• Beckwith-Wiedemann syndrome

BWS is the most common overgrowth syndrome characterized by large organs and body size. Macroglossia, ear lobe creases, helical creases, and omphalocele are common features as well. Patients with BWS are at an increased risk for embryonal tumors in childhood. These individuals typically have normal intelligence and attain a normal height and weight in adulthood. BWS is casued by alterations in methylation at two imprinting centers at 11p15.5.

Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis.

Sanger Sequencing

5-10% of de novo cases of BWS will have a sequence alteration in the CDKN1C gene. Sequencing of this gene identifies a pathogenic maternally inherited variant in 40% of familial cases.

The preferred sample type is 3-5 ml of peripheral blood collected in an EDTA (purple top) tube. Extracted DNA, dried blood spots, and saliva are also accepted for this test. Saliva samples must be submitted in an approved saliva kit. Contact the lab to receive a saliva kit or to have one sent to your patient.

The specimen should be kept at room temperature and delivered via overnight shipping. 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.

Prenatal diagnosis is available if the familial mutations are known or there are clinical features identified via ultrasound suggestive of a diagnosis in the fetus. 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.