Russell-Silver Syndrome Methylation-Specific MLPA

Clinical Information

Intrauterine growth restriction (IUGR) and postnatal growth deficiency are primary features of Russell-Silver syndrome. Individuals with RSS also commonly have developmental delay and characteristic triangular facies. These patients will not usually attain normal height or weight as adults.

Technical Information

A methylation sensitive MLPA assay is used to determine methylation status at the two imprinting centers and to identify microdeletions or duplications. If an abnormal methylation pattern is identified, then pyrosequencing is performed to quantify the methylation at these sites. This testing will detect approximately 50% of cases of Russell-Silver syndrome. The majority of these cases have isolated imprinting defects while less than 1% have microdeletions or duplications.

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.
• 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 may be available dependent on ultrasound findings and/or family history. Contact the laboratory prior to sending a prenatal specimen to confirm that requirements for receipt are met. 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 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.
The blood 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. Please contact the lab with any questions.
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.