Detection of DiGeorge syndrome (microdeletion 22q11.2)

The DiGeorge syndrome is the second most common cause of a delay in fetal development and of severe congenital heart defects [1, 2]. The postnatal prevalence is about 1: 4000 to 1: 6000 [2]. Recent data show that the prenatal prevalence can reach up to 1: 1000 [3].

The DiGeorge syndrome is caused by a submicroscopic deletion in chromosome 22. In most cases, the size of the deletion is about 3 megabases (MB), but in about 10-15% of cases it can be even smaller (1.5 MB or less.)

With the Harmony® Test it is now possible to detect and largely exclude the DiGeorge syndrome in the unborn child from maternal blood.

A first validation study showed that the Harmony® Test also detects 22q11.2 microdeletions of less than 3 MB [4].

In singleton pregnancies, the option of screening for the microdeletion 22q11.2 can be added to any of the existing Harmony® Test panels.

As each additional test option increases the overall false-positive rate of a non-invasive prenatal test [5], we recommend requesting the „DiGeorge syndrome“ test option only in pregnancies with an increased risk for this microdeletion.

You can order our latest test requisition form with the test option for DiGeorge syndrome here.

 

References:

[1]            Bassett et al. J Pediatr. 2011 Aug;1 59(2): 332-9

[2]           McDonald-McGinn et al. GeneReviews 1999 Sep 23

[3]           Grati FR et al. Prenat Diagn 2015; 35: 801–809

[4]           Schmid M et al. Fetal Diagn Ther 2017 Nov 8, E-pub ahead of print

[5]           Stumm M, Schröer A. Gynäkologe 2018; 51: 24-31

Public holidays

Please be advised that Cenata is operating reduced hours during the Easter period. Cenata will be closed on March 30 and April 2. We apologize for any inconvenience that this public holiday may cause to the timeliness of your test and results.

Temporary Analysis of the Harmony® Test by Medirex

In 1998 a patent was filed for the detectability of cell-free fetal DNA in maternal serum or plasma and its applications. This includes, amongst other things, also the diagnosis of fetal trisomy from maternal blood. The patent expires on March 4, 2018.

Currently, the patent holders, Sequenom and Illumina, file suits against providers of non-invasive prenatal tests (NIPT) worldwide, if these providers do not use the tests from these companies. In the USA, the related claims were finally revoked in 2014. In Germany, an action for revocation has also been filed against this patent with the Federal Patent Court, which is expected to be decided in April 2018.

Cenata and the company Roche have also been sued by the patent holders. A judgment by District Court in Mannheim is awaited. At the hearing before that court, the judge made it clear that the performance of the Harmony® Test in a patent-free country abroad would not infringe the patent in Germany.

Cenata will, therefore, have the Harmony® Test performed by the laboratory Medirex in Slovakia. Slovakia is a member of the European Union. This means that the high-quality Harmony® Test can be offered in the usual quality and with short turnaround times. The Medirex laboratory is the largest laboratory in Slovakia and, additionally, accredited in accordance with ISO 9001 and 15189 as well as CAP/CLIA. It is certified by Ariosa and Roche Diagnostics and licensed for the performance of the Harmony® Test. Thus, it is guaranteed that the Harmony® Test at Medirex is performed in accordance with the same high quality standards as is the case at Cenata.

For offering pregnant patients the Harmony® Test, it is necessary to use, with immediate effect, the new request form, where the patient consents to the performance of the test by the Medirex laboratory. Other than the use of this request form, nothing changes: The high quality, the short throughput times of the Harmony® Tests and the price remain unchanged. The test results will also continue to be validated by the physicians of Cenata.

In case of questions, the employees of the central office as well as the Managing Directors, are happy to be of service at any time. Please do not hesitate to call or send us an e-mail.