Prader-Willi Syndrome (Blood)

Testing Laboratory

Department

Diagnostic Genetics

Delphic Registration Code (Alpha Code)

DNAT

Test Code (Numeric Code)

7933

Laboratory Handling

Transport

Transport all bloods between >8 degrees C to <24 degrees C within 24-48 hours. If necessary specimens can be refrigerated overnight for transport at the temperatures stated above the following day. For testing of other sample types please contact the laboratory prior to sending.

Registration

Please store specimens at 4 degrees Celsius until processed.

Sample Stability

48 hours at ambient temperature (8 degrees C to 24 degrees C).

Associated Tests

• DNA Extraction and Storage (Blood)

Synonyms

Prader-willi syndrome genetic testing
Angelman Syndrome

Turnaround Time

6 weeks

Urgent TAT for prenatal/neonatal analysis: 2 weeks

Specimen Type

• Whole Blood

Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Lavender Cap)

Acceptable

• EDTA (Microtainer)

Preferred Sample Volume (ml)

8

Minimum Sample Volume (ml)

4

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Lavender Cap)

Acceptable

• EDTA (Microtainer)

Preferred Sample Volume (ml)

4

Minimum Sample Volume (ml)

0.5

Aliquot Instructions

Sample Type

• Whole Blood

Minimum Volume (ml)

4

Transport to Lab

Ambient (8 - 24 degrees Celsius)
If overnight - Chilled (2 - 8 degrees Celsius)

Additional Referral/Aliquot Information

Important Notes:

Diagnostic testing requires referral through Neurology, Paediatrics or Genetic Services.

Details of the patient phenotype must be provided. Failure to provide relevant clinical details may delay testing.

Contacts:

Genetic Health Service NZ can be contacted on 0800 476 123.

Neurology can be contacted on (09) 307 4949 ext. 25662.

General Paediatrics can be contacted on (09) 307 4949 ext. 22559.

Test Method

The methylation sensitive multiplex ligation-dependent probe amplification (MS-MLPA) kit ME028-D1 from MRC-Holland is used to detect copy number changes and to assess the methylation status of sequences within the Prader-Willi/Angelman region at chromosome 15q11.

Analysis was performed using Coffalyser.Net.

The sensitivity of this assay is estimated to be 99% for Prader-Willi syndrome and 80% for Angelman syndrome.

This assay may detect Prader-Willi/Angelman syndrome mosaicism when >50% affected cells are present in the sample.

Uncertainty of Measurement

Please contact the Diagnostic Genetics Pathologist at dgen@adhb.govt.nz to discuss sources of test uncertainty, which include, but are not limited to, measurement uncertainty (MU) and biological variation.

Contact Information