Discontinuation of the test option microdeletion 22q11.2 (DiGeorge syndrome)
28. March 2022
We have been analyzing the 22q11.2 microdeletion 22q11.2 (DiGeorge syndrome) as part of the Harmony® Test since July 2018. We now evaluated the data from more than 50000 cases.
The evaluation of the data shows that of the cases tested positive for DiGeorge syndrome with our Harmony® Test, only 5.4% were confirmed. Thus, our own data support the current publication record, based on a wide variety of NIPT technologies, on the low PPV of screening for fetal microdeletion 22q11.2 by NIPT [1]. In our study, additional testing for the 22q11.2 microdeletion increased the positive rate by 0.47 percentage points to over 0.5%. For testing for trisomies 21, 18 and 13 alone, the false positive rate of the Harmony® Test is less than 0.1%.
These results underline the statement of the working group around Prof. Nicolaides [2] that extending testing to chromosomes other than 13, 18 and 21 significantly increases the test positive rate by 0.4-0.8%. In addition, our data also support the statement by DEGUM that the use of NIPT, particularly for screening for microdeletions, is currently not recommended [3].
Based on the above results, we have decided to remove the test option “Microdeletion 22q11.2 / DiGeorge syndrome” from our test portfolio and will no longer offer it as of 04/01/2022.
You are welcome to continue using any existing request forms. You can also download or request new forms by contacting us.
Literatur:
[1] Martin K, Iyengar S, Kalyan A, et al (2017) Clinical Experience with a Single‐Nucleotide Polymorphism‐Based Noninvasive Prenatal Test for Five
Clinically Significant Microdeletions. Clinical genetics. doi.org/10.1111/cge.13098
[2] Jani JC, Gil MM, Benachi A et al, Genome-wide cfDNA testing of maternal blood, Ultrasound Obstet Gynecol. 2020;55:13-14
[3] https://www.degum.de/fileadmin/dokumente/sektionen/gynaekologie/Informationen_zum_Fach/NIPT-10-goldene-Regeln_AK_v2020-02-17.pdf
Discontinuation of the test option microdeletion 22q11.2 (DiGeorge syndrome)
28. March 2022
We have been analyzing the 22q11.2 microdeletion 22q11.2 (DiGeorge syndrome) as part of the Harmony® Test since July 2018. We now evaluated the data from more than 50000 cases.
The evaluation of the data shows that of the cases tested positive for DiGeorge syndrome with our Harmony® Test, only 5.4% were confirmed. Thus, our own data support the current publication record, based on a wide variety of NIPT technologies, on the low PPV of screening for fetal microdeletion 22q11.2 by NIPT [1]. In our study, additional testing for the 22q11.2 microdeletion increased the positive rate by 0.47 percentage points to over 0.5%. For testing for trisomies 21, 18 and 13 alone, the false positive rate of the Harmony® Test is less than 0.1%.
These results underline the statement of the working group around Prof. Nicolaides [2] that extending testing to chromosomes other than 13, 18 and 21 significantly increases the test positive rate by 0.4-0.8%. In addition, our data also support the statement by DEGUM that the use of NIPT, particularly for screening for microdeletions, is currently not recommended [3].
Based on the above results, we have decided to remove the test option “Microdeletion 22q11.2 / DiGeorge syndrome” from our test portfolio and will no longer offer it as of 04/01/2022.
You are welcome to continue using any existing request forms. You can also download or request new forms by contacting us.
