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Research group/lab  |  P.I. Tjakko van Ham, PhD

Functional Genetics Unit

We generate new diagnostically validated assays and use these to assist in improving diagnosing of a wide range of genetic disorders.

About our research group/lab

Our research

Our Research

We are a translation diagnostic research team, and our aim is to improve diagnostics for genetic disease in four ways. We have developed and diagnostically implemented:

  • Functional assays to assist in determining the effect of variants of unknown clinical significance on cells and protein function.
  • Functional assays to determine disease-related phenotype in patient samples, independent of whether causal DNA variants were identified.
  • mRNA-based diagnostics to determine the effect of variants on mRNA expression/splicing.
  • Transcriptome analysis/mRNA-sequencing to identify pathogenic variants in undiagnosed patients.

The diagnostic request form can be found on our laboratory page (in dutch). For questions you can contact us via e-mail.

Our projects

RNA sequencing in undiagnosed disorders

We have developed a pipeline to apply RNA-sequencing on patient-derived RNA – with aim to detect specific pathogenic changes in gene expression, including the effects of variants missed in exome/Sanger sequencing, such as deep intronic variants affecting mRNA splicing, or variants that are hard to interpret, including splice enhancers. 

Analysis of mRNA splicing

We routinely perform diagnostic analysis of mRNA splicing for given DNA variants of unknown clinical significance with unclear effects on mRNA splicing.

Analysis of variants of unknown significance (VUS)

The effect of VUS in several disease genes can be diagnostically tested in our lab, including variants in NF, TSC1/2, PTEN and the mTOR pathway.

Analysis of cellular phenotypes specific for genetic disorders

Some genetic disorders can be identified by measuring specific cellular phenotypes including DNA-repair disorders and the presence and function of cilia in suspected ciliopathies.


Collaborations include the following research laboratories:

Career opportunities

We welcome applications of students interested to work on innovative diagnostic procedures for genetic disorders.

Our team

  • Esmee Kasteleijn, BSc - Lab Technician/Analyst
  • Frans Verheijen, PhD - Clinical Biochemical Geneticist
  • Mark Nellist, PhD - Staff Researcher
  • Hannie Douben, BSc - Lab Technician/Analyst
  • Leontine van Unen, BSc - Lab Technician/Analyst
  • Marianne Hoogeveen, BSc - Analyst/Lab Manager
  • Peter Elfferich, BSc - Lab Technician/Analyst
  • Tjakko van Ham, PhD - Head FU/Assistant professor
  • Wendy Tra, PhD - Manager

Any questions?

Please contact our office if you have any questions or comments.

Contact form