Secret genetic defects can prompt a wide range of serious illnesses

Overview

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• Source: Radboud University Medical Center


• Date: 20 Mar,2021

For the first time researchers from Hebrew University of Jerusalem, Radboudumc, Maastricht UMC+ and worldwide colleagues have gained insight to the”hidden genetic defects” of the general European population. This is important as these defects, if inherited from the father and mother, can result in all kinds of disorders in their children.

Research in the Dutch and Estonian population proves that every individual has two to four these hidden genetic defects. In 1 in 100 couples, this also contributes to a situation with an increased risk of a genetic disease for future kids. In the event of consanguinity, even 20 percent of the couples appear to be at high risk. This research is published in The American Journal of Human Genetics and Genetics in Medicine.

Therefor you have two copies of each gene. Occasionally one of those two copies is defective, without making you sick because the other gene still functions properly. This type of hidden genetic defect can cause problems if a child inherits the identical hidden flaw, the same mutated gene, from the father and mother. Both parents are healthy and have never suffered from the hidden genetic defect. But when these two hidden genetic defects (maternal en paternal) come together in the child, the disease manifests itself.

Hidden flaws in sight
By screening all of the genes of nearly 6,500 people in the Dutch and Estonian population researchers from Radboudumc and Maastricht UMC+ have obtained insight into how often such hidden defects that may result in disease are present in one individual.

Every human being appears to have on average 2 to 4 such hidden genetic defects. Therefore the chance that a European couple is at risk of having a sick child due to two such defects is about 1 percent. The risk increases sharply in consanguineous couples. In a relationship of cousins, about sixteen percent of the couples are at high risk, with a particularly increased risks for skeletal disorders or intellectual disabilities.”

Christian Gilissen, Researcher, Radboudumc

Higher risk with consanguinity
In addition to this study, published in The American Journal of Human Genetics, research was also conducted in the hospital’s clinical practice coordinated by Maastricht UMC+, together with Radboudumc and Amsterdam UMC.

This study, published in Genetics in Medicine, addresses the question of risk determination of hidden genetic defects in cousin associations prior to a desired pregnancy. Clinical Molecular Geneticist Aimee Paulussen of Maastricht UMC+:”We mapped the threat in 100 consanguineous couples. About 20 percent of those couples were found to have an elevated risk of serious disorders in their offspring using these hidden genetic defects. These outcomes from clinical practice confirm the data already found in the population study mentioned above.”

Valuable testing
Professor Han Brunner, head of the Department of Clinical Genetics Maastricht as well as the Department of Genetics Nijmegen, is involved in both studies. He sees them as a clear incentive to make genetic testing available to couples with a potential increased risk because of these hidden genetic defects:”Certainly for these couples, this information can help them to make an educated choice when starting a family. They can consider pre-implantation diagnostics and IVF to permit selection of embryos with no defects.”