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S. (Sam) Riedijk, PhD

Medical psychologist, assistant professor

Medical psychologist, assistant professor

  • Department
  • Clinical Genetics
  • Focus area
  • Prenatal genetic testing



As a counselor, I am familiar with the challenges and expectations of patients opting for genetic counseling. My aim is to conduct clinically based psychological research enabling us to offer adequate psychological support in the rapidly advancing field of clinical genetics. Over the past five years my attention has focused on the broadening scope of prenatal genetic testing and its implications for patient informed decision-making and well-being. Over the next five years I aim to expand my focus to the psychological aspects of the introduction of genome editing techniques in patient treatment of monogenic disorders such as Huntington’s and Pompe disease.

Field(s) of expertise

I am principal investigator of the "Horizon study: Broadening the horizon of non-invasive and invasive prenatal genetic testing; do pregnant couples want more?"

Education and career

In addition to research I have developed and coordinate the minor Genetics in Society, which is open to third year university students. Currently, I am involved in a SKO trajectory (senior education qualification). My main area of patient care is in prenatal genetics. I offer decision-counseling and support to pregnant couples who decide about the course of their pregnancy when fetal anomalies have been found. 


Van der Steen SL, Diderich KEM, Verhagen-Visser J, Govaerts LCP, Joosten M, Knapen MFCM, et al., Riedijk SR (2017). Choosing between Higher and Lower Resolution Microarrays: do Pregnant Women Have Sufficient Knowledge to Make Informed Choices Consistent with their Attitude? J Genet couns². doi: 10.1007/s10897-017-0124-5. [Epub ahead of print]

Van der Steen SL*, Riedijk, SR*, Verhagen-Visser J, Govaerts LCP, Van Opstal A, De Vries FAT, et al. (2016). Receiving a susceptibility locus as a result from SNP array in prenatal genetic testing: quick recovery after initial shock. J Genet Couns². 25(6):1227-1234. 
* van der Steen and Riedijk are joint first authors

Van der Steen SL*, Diderich KEM*, Riedijk SR, Verhagen-Visser J, Govaerts LCP, Joosten M, et al. (2014). Pregnant Couples at Increased Risk for Common Aneuploidies Prefer Maximal Information From Invasive Genetic Testing. Clin Genet². 88(1):25-31
*Diderich and van der Steen are joint first authors

Invited publication
Riedijk SR, Diderich, KEM, van der Steen SL, Govaerts LCP, Joosten M, Knapen MFCM, et al. (2014). The Psychological Challenges of Replacing Conventional Karyotyping with Genomic SNP Array
Analysis in Prenatal Testing. J. Clin. Med, 3(3): 713-723. Special issue ""Prenatal Genetic Screening and Diagnosis-Part 2""

Srebniak MI, Diderich KEM, Govaerts LCP, Joosten M, Riedijk SR, Galjaard RJ, et al. (2013).Types of array findings detectable in cytogenetic diagnosis: a 
proposal for a generic classification. Eur J Hum Genet¹, 22(7): 856-858.

Invited publication
Riedijk SR, Oudesluijs G & Tibben A. (2012 ). Psychosocial aspects of preconception consultation in primary care: lessons from our experience in clinical genetics. J Community Genet, 3(3): 213-219. Special issue “Genetic Aspects of Preconception Consultation in Primary Care.