Israeli scientists fix flaw in prenatal tests for Jews and other minorities

A team at Rabin Medical Centre has unveiled a new genetic risk assessment model designed to give expectant parents from close-knit ethnic groups – including Jews – more accurate results during prenatal screening.

The system, led by Prof. Idit Maya, acting director of the hospital’s Genetics Institute, addresses what she calls “a major flaw” in global testing standards, which are based on genetically mixed populations.

Maya said using these benchmarks for communities with shared ancestry – such as Jews, Druze, Circassians, and others – can trigger unwarranted concern. “Measuring the genetic proximity of Jewish couples using the same yardstick as American couples is a mistake. Some level of relatedness is expected… If we don’t take that into account, we end up with false red flags that can lead to heartbreaking decisions, including unnecessary terminations,” she explained.

The research began in 2017, when Maya partnered with Prof. Lena Sagi-Dain, chair of the Israeli Society of Medical Genetics. Analysing 15,000 blood and embryo samples from 16 ethnic groups in Israel, they found significant differences in the length and frequency of “runs of homozygosity” – stretches of identical DNA inherited from both parents – between populations.

These patterns often reflect generations of marriage within the same community, rather than a heightened risk of genetic disorders. The team’s algorithm adjusts for this by setting a population-specific “true risk threshold” instead of applying a rigid cut-off.

The Israeli Society of Medical Genetics adopted the model in late July, with plans to integrate it into national clinical guidelines.

Maya believes the shift will reduce needless stress for families, prevent healthy pregnancies from being terminated, and strengthen personalised medicine. “This is a big step forward – not just for individuals, but for entire communities,” she said.