Prader-Willi syndrome

Required sample material

Molecular genetic tests:
3-7 ml EDTA blood, for small children a smaller amount of blood (1-3 ml) is usually sufficient
or extracted DNA

Molecular genetic prenatal diagnostics:
15-20 ml amniotic fluid or cultured amniotic cells
In addition, blood or DNA from the pregnant woman (to rule out maternal contamination)

Chromosome diagnostics:
heparinised whole blood (adults 5-7 ml, children approx. 5 ml, newborns 1-2 ml)
NH4 heparinate S monovettes (Sarstedt REF 01.1603) or disposable syringes with approx. 20 to max. 200 µl heparin sodium (5000 I.U./ml) (final concentration 10 to max. 100 I.U. heparin/ml sample material). Please do not send Li heparin or EDTA blood!

Molecular cytogenetic diagnostics (FISH):
5-7 ml heparin whole blood (NH4), for small children a smaller amount of blood (1-2 ml) is usually sufficient.
NH4 heparinate S monovettes (Sarstedt REF 01.1603) or disposable syringes with approx. 20 to max. 200 µl heparin sodium (5000 I.U./ml) (final concentration 10 to max. 100 I.U. heparin/ml sample material). Please do not send Li heparin or EDTA blood!

EDTA blood samples and extracted DNA for molecular genetic analyses can usually be sent unrefrigerated by normal post, as the DNA extracted from the leucocytes is very stable. Intermediate storage (blood max. 7 days) should take place in the refrigerator.

Heparin whole blood for cytogenetic and molecular cytogenetic analyses should be sent unrefrigerated by express mail. The sample transport time is of greater importance in cytogenetics, as cell cultures almost always have to be created here. The test material should reach the laboratory within 24 hours.

Please send the samples to the following address:

Heidelberg University Hospital
Institute of Human Genetics

depending on the test requested:

Laboratory for Molecular Genetic Diagnostics/
Laboratory for Molecular Cytogenetic Diagnostics/
Laboratory for Cytogenetic Diagnostics

Im Neuenheimer Feld 366
69120 Heidelberg

Please label each sample container clearly with the surname, first name and date of birth of the patient and use our request forms. Our request forms are structured in such a way that we have all the necessary information about the patient and the test order. Please fill in the request forms carefully to avoid unnecessary enquiries and please understand that we cannot accept unlabelled sample containers.

Request form for molecular genetics (German) (English)

Request form for cytogenetics and FISH diagnostics

Further information

OMIM: 176270

Sensible procedure:
A molecular genetic test (methylation-sensitive MLPA) and cytogenetic clarification should be performed first.
If the methylation test is positive, a molecular genetic microsatellite analysis is recommended to clarify the underlying defect.

Note:
Prenatal diagnostics can only be carried out from amniotic cells, as the methylation process is not yet complete at the time of the chorionic villus sampling.

Processing time: On average 1-2 weeks
In rare cases, the processing time may be delayed by approx. 2 weeks.