About T.J. (Tjakko) van Ham, Associate professor
Introduction
I’m currently head of the Clinical Genetics Laboratories (genomic and metabolic labs) and an associate professor in “Translational and Functional Genomics”. My main research interest is to discover genetic disease causes that are currently missed in routine diagnostics. My current research involves whole genome sequencing and long-read DNA/RNA sequencing in undiagnosed genetic disorders. Previous research includes genetic disease modeling using model organisms (C. elegans, zebrafish), biochemical and cell culture models, and discovery of new disease mechanisms and disease genes.
Field(s) of expertise
A goal of our diagnostic laboratories is to improve care for patients with, or suspected of, genetic disorders. Recent advances including whole genome sequencing, long-read DNA/RNA sequencing, other “omics”, such as metabolomics, and improving analysis capabilities (e.g. AI) likely allow greater care for patients with genetic disorders. Greater care is not limited to identifying more diagnoses, but also making the diagnostic process more efficient, and fully taking advantage of the information offered by whole genome sequencing for prevention, pharmacogenomics and polygenic risk scores or the analysis of biomarkers. To achieve this we need to translate such innovative approaches and catalyze their implementation into the clinical diagnostic laboratory to take full advantage of this opportunity and improve care for genetic disease. These efforts are spearheaded by our translational genomics team.
Education and career
2004 MSc, Fundamental Biomedical Sciences, Utrecht University
2009 PhD, Functional genomics: Genetic screening in C. elegans neurodegenerative disease models, Rijksuniversiteit Groningen/UMC Groningen
2009-2012 Postdoctoral training, Massachusetts General Hospital, Boston, USA
2012-2014 ZonMW VENI/Marie Curie fellow, UMC Groningen
2014-2023 Research group leader, Erasmus MC
2022- Associate Professor
2023- Clinical Laboratory Geneticist
2024- Head Clinical Genetics Laboratory
Publications
For a complete overview of publications: van ham t - Search Results - PubMed
Recent (shared) last author publications:
Long-read DNA and RNA sequencing reveal an intronic retrotransposon insertion in TCOF1 causing Treacher Collins syndrome. Ferraro F et al., HGG Adv. 2025 Sep 27:100523. doi: 10.1016/j.xhgg.2025.100523. PMID: 41017149. Long-read DNA and RNA sequencing reveal an intronic retrotransposon insertion in TCOF1 causing Treacher Collins syndrome - ScienceDirect
Routine RNA-based analysis of potential splicing variants facilitates genomic diagnostics and reveals limitations of in silico prediction tools. Drost M et al., HGG Adv. 2025 Sep 22:100521. doi: 10.1016/j.xhgg.2025.100521. PMID: 40988334. Routine RNA-based analysis of potential splicing variants facilitates genomic diagnostics and reveals limitations of in silico prediction tools - ScienceDirect
The non-canonical thioreductase Tmx2b is essential for neuronal survival during zebrafish embryonic brain development. Development. Dekker J et al., 2025 Sep 15;152(18):dev204348. doi: 10.1242/dev.204348. PMID: 40891441. The non-canonical thioreductase Tmx2b is essential for neuronal survival during zebrafish embryonic brain development | Development | The Company of Biologists
Human ITGAV variants are associated with immune dysregulation, brain abnormalities, and colitis, Ghasempour S et al., J Exp Med. 2024 Dec 2;221(12), doi: 10.1084/jem.20240546 Human ITGAV variants are associated with immune dysregulation, brain abnormalities, and colitis | Journal of Experimental Medicine | Rockefeller University Press
Biallelic variants in FLII cause pediatric cardiomyopathy by disrupting cardiomyocyte cell adhesion and myofibril organization. Ruijmbeek CW et al., JCI Insight. 2023 Sep 8;8(17):e168247. doi: 10.1172/jci.insight.168247. JCI Insight - Biallelic variants in FLII cause pediatric cardiomyopathy by disrupting cardiomyocyte cell adhesion and myofibril organization
Web-accessible application for identifying pathogenic transcripts with RNA-seq: Increased sensitivity in diagnosis of neurodevelopmental disorders. Dekker J et al., Am J Hum Genet. 2023 Feb 2;110(2):251-272. doi: 10.1016/j.ajhg.2022.12.015 Web-accessible application for identifying pathogenic transcripts with RNA-seq: Increased sensitivity in diagnosis of neurodevelopmental disorders - ScienceDirect
High-yield identification of pathogenic NF1 variants by skin fibroblast transcriptome screening after apparently normal diagnostic DNA testing. Douben HCW et al., Hum Mutat. 2022 Oct 17. doi: 0.1002/humu.24487. PMID: 36251260. High-yield identification of pathogenic NF1 variants by skin fibroblast transcriptome screening after apparently normal diagnostic DNA testing - PubMed
Dominant-acting CSF1R variants cause microglial depletion and altered astrocytic phenotype in zebrafish and adult-onset leukodystrophy. Berdowski WM et al., Acta Neuropathol. 2022 Aug;144(2):211-239. doi: 10.1007/s00401-022-02440-5. Dominant-acting CSF1R variants cause microglial depletion and altered astrocytic phenotype in zebrafish and adult-onset leukodystrophy | Acta Neuropathologica
Bi-allelic variants in HOPS complex subunit VPS41 cause cerebellar ataxia and abnormal membrane trafficking, Sanderson LE et al., Brain, 2022 Bi-allelic variants in HOPS complex subunit VPS41 cause cerebellar ataxia and abnormal membrane trafficking | Brain | Oxford Academic
Zebrafish macrophage developmental arrest underlies depletion of microglia and reveals Csf1r-independent metaphocytes. Kuil LE et al., Elife. 2020 May 5;9:e53403. doi: 10.7554/eLife.53403. PMID: 32367800. Zebrafish macrophage developmental arrest underlies depletion of microglia and reveals Csf1r-independent metaphocytes | eLife
Recent (shared) last author publications:
Long-read DNA and RNA sequencing reveal an intronic retrotransposon insertion in TCOF1 causing Treacher Collins syndrome. Ferraro F et al., HGG Adv. 2025 Sep 27:100523. doi: 10.1016/j.xhgg.2025.100523. PMID: 41017149. Long-read DNA and RNA sequencing reveal an intronic retrotransposon insertion in TCOF1 causing Treacher Collins syndrome - ScienceDirect
Routine RNA-based analysis of potential splicing variants facilitates genomic diagnostics and reveals limitations of in silico prediction tools. Drost M et al., HGG Adv. 2025 Sep 22:100521. doi: 10.1016/j.xhgg.2025.100521. PMID: 40988334. Routine RNA-based analysis of potential splicing variants facilitates genomic diagnostics and reveals limitations of in silico prediction tools - ScienceDirect
The non-canonical thioreductase Tmx2b is essential for neuronal survival during zebrafish embryonic brain development. Development. Dekker J et al., 2025 Sep 15;152(18):dev204348. doi: 10.1242/dev.204348. PMID: 40891441. The non-canonical thioreductase Tmx2b is essential for neuronal survival during zebrafish embryonic brain development | Development | The Company of Biologists
Human ITGAV variants are associated with immune dysregulation, brain abnormalities, and colitis, Ghasempour S et al., J Exp Med. 2024 Dec 2;221(12), doi: 10.1084/jem.20240546 Human ITGAV variants are associated with immune dysregulation, brain abnormalities, and colitis | Journal of Experimental Medicine | Rockefeller University Press
Biallelic variants in FLII cause pediatric cardiomyopathy by disrupting cardiomyocyte cell adhesion and myofibril organization. Ruijmbeek CW et al., JCI Insight. 2023 Sep 8;8(17):e168247. doi: 10.1172/jci.insight.168247. JCI Insight - Biallelic variants in FLII cause pediatric cardiomyopathy by disrupting cardiomyocyte cell adhesion and myofibril organization
Web-accessible application for identifying pathogenic transcripts with RNA-seq: Increased sensitivity in diagnosis of neurodevelopmental disorders. Dekker J et al., Am J Hum Genet. 2023 Feb 2;110(2):251-272. doi: 10.1016/j.ajhg.2022.12.015 Web-accessible application for identifying pathogenic transcripts with RNA-seq: Increased sensitivity in diagnosis of neurodevelopmental disorders - ScienceDirect
High-yield identification of pathogenic NF1 variants by skin fibroblast transcriptome screening after apparently normal diagnostic DNA testing. Douben HCW et al., Hum Mutat. 2022 Oct 17. doi: 0.1002/humu.24487. PMID: 36251260. High-yield identification of pathogenic NF1 variants by skin fibroblast transcriptome screening after apparently normal diagnostic DNA testing - PubMed
Dominant-acting CSF1R variants cause microglial depletion and altered astrocytic phenotype in zebrafish and adult-onset leukodystrophy. Berdowski WM et al., Acta Neuropathol. 2022 Aug;144(2):211-239. doi: 10.1007/s00401-022-02440-5. Dominant-acting CSF1R variants cause microglial depletion and altered astrocytic phenotype in zebrafish and adult-onset leukodystrophy | Acta Neuropathologica
Bi-allelic variants in HOPS complex subunit VPS41 cause cerebellar ataxia and abnormal membrane trafficking, Sanderson LE et al., Brain, 2022 Bi-allelic variants in HOPS complex subunit VPS41 cause cerebellar ataxia and abnormal membrane trafficking | Brain | Oxford Academic
Zebrafish macrophage developmental arrest underlies depletion of microglia and reveals Csf1r-independent metaphocytes. Kuil LE et al., Elife. 2020 May 5;9:e53403. doi: 10.7554/eLife.53403. PMID: 32367800. Zebrafish macrophage developmental arrest underlies depletion of microglia and reveals Csf1r-independent metaphocytes | eLife
Teaching activities
2021 BKO/UTQ University Teaching Qualification, Erasmus University
PhD theses supervised
2018 Nynke Oosterhof, “Microglia in health and disease: learning from the zebrafish”
2019 Laura Kuil, “Genetics of tissue macrophage development and function: from zebrafish to human disease”
2024 Woutje Berdowski, ”Glial cellular mechanisms in genetic white matter disorders: from zebrafish models to patients”
2024 Jordy Dekker, “Neurodevelopmental disorders: from clinical phenotypes and genome analysis to gene function”
2024 Claudine Ruijmbeek, “Unraveling genetic cardiomyopathies: From gene discovery to mechanistic insights and clinical implications”
