Tjitske Kleefstra

Dr Tjitske Kleefstra Dutch Clinical Geneticist

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

Medical Eponyms
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

Major Publications


Dr Charlotte Baker LITFL

Studied at Univerisity of Cambridge - BA MB BChir. British doctor working in emergency medicine in Perth, Australia. Special interests include primary care and emergency medicine.

BA MA (Oxon) MBChB (Edin) FACEM FFSEM. Emergency physician, Sir Charles Gairdner Hospital.  Passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |

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