Gijs Santen appointed professor

8 July 2024
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Prof. dr. Gijs Santen has been appointed Professor of Clinical Genetics. His teaching assignment is to apply his expertise, the interpretation of writing errors in genetic material and their translation into the clinic, to pioneer innovations that benefit patients.

A good example of this kind of innovation is the pioneering work he did with colleagues in the Departments of Clinical Genetics and Obstetrics. They offered, the first worldwide, a more detailed genetic test for fetuses diagnosed with a congenital defect during pregnancy. This marked a major step forward in prenatal care. He is currently supervising research on patient experiences with this new test.

He is also committed to relatively rare developmental disorders, such as Coffin-Siris syndrome, one of the most common causes of genetically determined intellectual disability. Santen: "In the coming years, we hope to better understand the syndrome at the cellular level. And in addition, working closely with patient organizations and colleagues in the Faculty of Social Sciences at Leiden University, we want to take steps to ensure that possible treatments being developed now can soon be tested in patients with this syndrome." Recently, Santen and his colleagues at CHDR already tested the drug clonazepam in this patient group with a grant from ZonMw, unfortunately without effect.

"I remain involved in patient care around prenatal diagnosis and Coffin-Siris syndrome, and see broad opportunities for further innovation," says Santen, “For example, with our laboratory specialists on Genome Diagnostics, by introducing the so-called long read sequencing. With this we can not only map hereditary material much better, but also get information about the methylation of the DNA. I also see opportunities to innovate with the clinical geneticists in the outpatient clinic. For example, by bringing the genetic test more to the forefront of the diagnostic process. Previously, this was often the final step if all kinds of other tests did not yield anything. Because the genetic test is now much better than before, it may be more effective to use that test earlier in the diagnostic process."

Teaching the specialty of Clinical Genetics

Santen enjoys teaching clinical genetics in the studies of Biomedical Sciences, Medicine and Clinical Technology. "I also teach AIOS clinical genetics and further education to specialties we work with, such as pediatricians, gynecologists and neurologists."


Studied Biopharmaceutical Sciences and Medicine in Leiden. He did his PhD research at the LACDR on clinical trials in the field of antidepressants. He completed his education as a clinical geneticist and started working as a clinical geneticist at LUMC in 2016. Since 2023, Santen has held the role of Department Head of Clinical Genetics.

More information

Long read sequencing

So far, DNA has been mapped by reading short pieces of DNA (about 150 base pairs). With new techniques, it is possible to read pieces ranging from 10,000 to as many as 100,000 base pairs, making it much easier to identify certain types of changes in DNA.

DNA methylation

In addition to the DNA code itself, with the letters A, T, C and G, which basically do not change from generation to generation, there are also modifications of DNA that can vary by cell type. A well-known example is methylation of Cs sitting next to a G, which is usually a signal for the cell not to read the piece of DNA in question. Sometimes DNA methylation can also be used as a marker in diagnostics.