Presence of ATM protein and residual kinase activity correlates with the phenotype in ataxia-telangiectasia: A genotype-phenotype study

Mijke M. M. Verhagen, James I. Last, Frans B. L. Hogervorst, Dominique F. C. M. Smeets, Nel Roeleveld, Frans Verheijen, Coriene E. Catsman-Berrevoets, Nico M. Wulffraat, Jan M. Cobben, Johan Hiel, Ewout R. Brunt, Els A. J. Peeters, Encarna B. Gomez Garcia, Marjo S. van der Knaap, Carsten R. Lincke, Laura A. E. M. Laan, Marina A. J. Tijssen, Monique A. van Rijn, Danielle Majoor-Krakauer, Marjan VisserLaura J. van 't Veer, Wim J. Kleijer, Bart P. C. van de Warrenburg, Adilia Warris, Imelda J. M. de Groot, Ronald de Groot, Annegien Broeks, Frank Preijers, Berry H. P. H. Kremer, Corry M. R. Weemaes, Malcolm A. M. R. Taylor, Marcel van Deuren, Michel A. A. P. Willemsen*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

103 Citations (Web of Science)


Ataxia-telangiectasia (A-T) is an autosomal recessive neurodegenerative disorder with multisystem involvement and cancer predisposition, caused by mutations in the A-T mutated (ATM) gene. To study genotypephenotype correlations, we evaluated the clinical and laboratory data of 51 genetically proven A-T patients, and additionally measured ATM protein expression and kinase activity. Patients without ATM kinase activity showed the classical phenotype. The presence of ATM protein, correlated with slightly better immunological function. Residual kinase activity correlated with a milder and essentially different neurological phenotype, absence of telangiectasia, normal endocrine and pulmonary function, normal immunoglobulins, significantly lower X-ray hypersensitivity in lymphocytes, and extended lifespan. In these patients, cancer occurred later in life and generally consisted of solid instead of lymphoid malignancies. The genotypes of severely affected patients generally included truncating mutations resulting in total absence of ATM kinase activity, while patients with milder phenotypes harbored at least one missense or splice site mutation resulting in expression of ATM with some kinase activity. Overall, the phenotypic manifestations in A-T show a continuous spectrum from severe classical childhood-onset A-T to a relatively mild adult-onset disorder, depending on the presence of ATM protein and kinase activity. Each patient is left with a tremendously increased cancer risk. Hum Mutat 33:561571, 2012.
Original languageEnglish
Pages (from-to)561-571
JournalHuman Mutation
Issue number3
Publication statusPublished - Mar 2012


  • ataxia-telangietasia
  • AT
  • genotype-phenotype
  • cancer
  • ATM

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