Tjitske Kleefstra is a Dutch Clinical Geneticist.
Tjitske Kleefstra is a clinical geneticist at the Department of Genetics at Radboud university medical center, where she was recently appointed as professor by special appointment in September 2020. Her work focuses on scientific research, specialist patient care, and education in the field of developmental disorders with a genetic cause.
Amongst her extensive research in the field of genetics, Kleefstra et al were the first to recognise and describe the 9q subtelomere deletion syndrome (9qSTDS), which has since been renamed enponymously after her as Kleefstra syndrome.
- Born 4 March 1970
- 1994 – MSc with Doctorate of Medical Biology, and Doctorate of Medicine, University of Utrecht
- 1997 – MD, University of Utrecht
- 2005 – PhD, Radboud University Nijmegen. Thesis: Genotypes and phenotypes in X-linked mental retardation.
- 2005-2007 Medical specialist in training (clinical genetics) at Radboudumc, Nijmegen
- 2007 – Senior clinical geneticist at Radboudumc, Nijmegen
- 2016 – Principal Investigator – Donders Institute for Brain, Cognition and Behaviour
- Dutch National Prize for Research in Clinical Genetics (Ter Haar Award); European Society of Human Genetics for research Award (Oberlé award)
- 2020 – Appointed as professor by special appointment at the Radboud university medical center
Kleefstras syndrom (Kleefstra syndrome)
Kleefstra syndrome (KS), previously known as the 9q subtelomere deletion syndrome (9qSTDS) is clinically characterised by moderate to severe mental retardation, childhood hypotonia and facial dysmorphisms. In addition, congenital heart defects, urogenital defects, epilepsy and behavioural problems are frequently observed. The syndrome can be either caused by a submicroscopic 9q34.3 deletion or by intragenic EHMT1 mutations leading to haploinsufficiency of the EHMT1 gene.
2009 – Kleefstra et al reported 16 patients with 9q deletions identified by routine chromosome testing or whole genome array analysis and 6 additional patients with intragenic EHMT1 mutations and normal chromosome studies. They concluded that haploinsufficiency for the EHMT1 gene is responsible for the main phenotypic features
- Kleefstra T, Brunner HG, Amiel J, et al. Loss-of-function mutations in euchromatin histone methyl transferase 1 (EHMT1) cause the 9q34 subtelomeric deletion syndrome. Am J Hum Genet. 2006;79(2):370-377
- Stewart DR, Kleefstra T. The chromosome 9q subtelomere deletion syndrome. Am J Med Genet C Semin Med Genet. 2007;145C(4):383-392.
- Kleefstra T, van Zelst-Stams WA, Nillesen WM, et al. Further clinical and molecular delineation of the 9q subtelomeric deletion syndrome supports a major contribution of EHMT1 haploinsufficiency to the core phenotype. J Med Genet. 2009;46(9):598-606.
- Kleefstra T, de Leeuw N. Kleefstra Syndrome. In: Adam MP, Ardinger HH, Pagon RA, et al., eds. GeneReviews®. Seattle (WA): University of Washington, Seattle; October 5, 2010.
- Verhoeven WM, Egger JI, Vermeulen K, van de Warrenburg BP, Kleefstra T. Kleefstra syndrome in three adult patients: further delineation of the behavioral and neurological phenotype shows aspects of a neurodegenerative course. Am J Med Genet A. 2011;155A(10):2409-2415
- Kleefstra T, Kramer JM, Neveling K, et al. Disruption of an EHMT1-associated chromatin-modification module causes intellectual disability. Am J Hum Genet. 2012;91(1):73-82.
- Dr Kleefstra. Kleefstrasyndrom.org
- Tjitske Kleefstra MD PhD. Radboud universitair medisch centrum
- Dr. T. Kleefstra (Tjitske). Radboud Universiteit
- KLEEFSTRA SYNDROME 1; KLEFS1. OMIM
- Bibliography. Kleefstra, Tjitske. WorldCat Identities
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