Beckwith-Wiedemann Syndrome Methylation-Specific MLPA

Clinical Information

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.

Technical Information

Methylation Specific-Multiplex Ligation-dependent Probe Amplification (MS-MLPA) analysis is performed to determine if deletions, duplications, or methylation defects involving the imprinting center region 1 (ICR1) or imprinting center region 2 (ICR2) on 11p15.5 are present. MS-MLPA analysis allows for the determination of dosage for specific sequences of interest (Schouten et al. (2002) Nucleic Acids Research 30, e57) as well as for methylation status at several differentially methylated HhaI restriction sites. Genomic DNA is hybridized with probes that correspond to the CpG islands in the promoters of the H19 gene (ICR1) and the KCNQ1OT1 gene (ICR2) to determine dosage and methylation status of the DNA in that region.

Specimen Requirements

• The preferred sample type is 3-4 ml of peripheral blood collected in an EDTA (purple top) tube. Extracted DNA and saliva are also accepted for this test. Blood and saliva kits are available by request.
• Send approximately 5µg of extracted DNA at a requested concentration of 90-130 ng/µl. Bead-based extraction is strongly discouraged for MS-MLPA.
• Saliva samples must be submitted in an approved saliva kit.

Transport Instructions

• The blood 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.
• Extracted DNA should be sent at room temperature via overnight delivery.
• Saliva is stable at room temperature and can be delivered via overnight or ground shipping.

Prenatal Testing Information

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.

Prenatal diagnosis may be available if there are clinical features identified on ultrasound suggestive of Beckwith-Wiedemann syndrome. Amniotic fluid must be collected at a minimum of 16 weeks for MS-MLPA results to be informative. CVS samples are not accepted for this methylation-based test. 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 to confirm that requirements for receipt are met.

Prenatal Specimen Requirements

• Amniotic Fluid: Direct amniotic fluid will be accepted for analysis given there is sufficient volume for back-up culture to be established. A back-up culture at a reference lab OR Greenwood lab is required. Additional charges may apply if cell culture is required after receipt of the sample. If sending direct fluid for molecular analysis only, 10-20 ml of amniotic fluid is requested. Chromosome studies will require an additional 10-15 ml of fluid.
• CVS samples are not accepted for this methylation-based test.
• A maternal sample is required, and accepted sample types include blood, saliva, and extracted DNA. Please refer to the specimen requirements above for more information.

Prenatal Transport Instructions

• Amniotic fluid should be kept at room temperature; do not freeze or refrigerate. Specimen should be sent by courier or overnight mail to arrive at the laboratory the next day. FedEx is preferred.
• Please refer to the transport instructions above for sending the maternal sample.