Breakthrough model helps reduce false genetic warnings during pregnancy

A research team at Rabin Medical Center (Israel) has developed a groundbreaking model that could fundamentally change the way genetic risk is assessed for Jewish couples preparing to become parents.

With thresholds built on mixed genetic populations like those in the US or Europe, many Jewish couples around the world can now be told that they are “closely related” when undergoing early pregnancy screening.

However, applying this standard to communities of common ancestry, such as Jews, Druze, Circassians or other ethnic minorities, often leads to unnecessary anxiety and even consideration of termination of pregnancy.

Professor Idit Maya, acting director of the Institute of Genetics at Rabin Medical Center, who led the research team, said her study pointed to a “serious flaw” in the current way of assessing genetic disease risk.

“Measuring the genetic closeness of Jewish couples using the same criteria as American couples is a mistake,” Maya stresses. “A certain degree of genetic similarity is to be expected in Jewish communities, which have intermarried for generations. Failure to account for this can lead to false alarms and heartbreaking decisions, such as unnecessary termination of pregnancies.”

Professor Maya began her research several years ago, after repeatedly seeing Jewish couples receive alarming genetic reports from foreign clinics – which did not fully understand the unique genetic makeup of Ashkenazi Jews.

To test her hypothesis, she teamed up with Professor Lena Sagi-Dain, President of the Israel Society of Medical Genetics and Head of the Prenatal Genetics Unit at Carmel Medical Center in Haifa.

Since 2017, the team has collected and analyzed about 15,000 genetic samples at Rabin Medical Center, including data from blood and embryos.

The samples were classified by ethnic origin - there are about 16 different ethnic groups in Israel, including Jews from regions such as Bukhara, Iran, Kurdistan, Iraq, Syria, Lebanon, Libya, Afghanistan, Yemen and Ethiopia. They also studied Arab Christians, Muslims, Bedouins and Druze.

Human DNA comes in pairs—one from each parent. When a segment of DNA is identical in both copies, it’s called “run of homozygosity” (ROH). ROH often occurs in people whose ancestors lived in the same small community, causing them to share many genetic traits.

The team measured the proportion of identical DNA segments in each genome sample and found that the size and frequency of these segments varied greatly between ethnic groups.

Professor Maya found that the longer the overlap, the higher the likelihood that the parents had a common ancestor - something that is common in Jewish communities, where intermarriage occurs over many generations.

The result is a new algorithm that assesses the risk of genetic disease based on the genetic profile of each community. Instead of using rigid thresholds, the model provides “true risk thresholds” based on specific data for each population.

Current guidelines in the US and Europe are based on data from millions of people of diverse backgrounds, which sometimes makes the assessments irrelevant for genetically homogeneous communities like Jews, according to Professor Maya.

The Israel Society of Medical Genetics officially adopted the new model in late July and is expected to be incorporated into Israel’s updated clinical guidelines. The new model is expected to reduce unnecessary concerns and “prevent false alarms”./.

(Vietnam+)

Source: https://www.vietnamplus.vn/mo-hinh-dot-pha-giup-han-che-canh-bao-di-truyen-sai-trong-thai-ky-post1055197.vnp