Balanced into array: genome-wide array analysis in 54 patients with an apparently balanced de novo chromosome rearrangement and a meta-analysis

Conny M.A. van Ravenswaaij-Arts (1) , Ilse Feenstra (1) , Nicolien Hanemaaijer (1) , Birgit Sikkema-Raddatz (1) , Helger Yntema (1) , Trijnie Dijkhuizen (1) , Dorien Lugtenberg (1) , Joke B.G.M. Verheij (1) , Andrew Green (1) , Roel Hordijk (1) , William Reardon (1) , Bert Ba de Vries (1) , Han G Brunner (1) , Ernie Mhf Bongers (1) , Nicole de Leeuw (1)

1 Department of Genetics

High resolution genome-wide array analysis enables detailed screening for cryptic and submicroscopic imbalances of microscopically balanced de novo rearrangements in patients with developmental delay and/or congenital abnormalities. In this report we added the results of genome-wide array analysis in 54 patients to data on 117 patients from seven other studies. A chromosome imbalance was detected in 37% of all patients with two-breakpoint rearrangements. In 49% of these patients the imbalances were located in one or both breakpoint regions. Imbalances were more frequently (90%) found in complex rearrangements, with the majority (81%) having deletions in the breakpoint regions. The size of our own cohort enabled us to relate the presence of an imbalance to the clinical features of the patients by using a scoring system, the De Vries criteria, that indicates the complexity of the phenotype. The median De Vries score was significantly higher (p=0.002) in those patients with an imbalance (5, range 1-9) than in patients with a normal array result (3, range 0-7). This study provides accurate percentages of cryptic imbalances that can be detected by genome-wide array analysis in simple and complex de novo microscopically balanced chromosome rearrangements and confirms that these imbalances are more likely to occur in patients with a complex phenotype.

Mots clés: Array analysis; de novo translocation; complex chromosome rearrangement

Conny M.A. van Ravenswaaij-Arts, Ilse Feenstra, Nicolien Hanemaaijer, Birgit Sikkema-Raddatz, Helger Yntema, et al.. Balanced into array: genome-wide array analysis in 54 patients with an apparently balanced de novo chromosome rearrangement and a meta-analysis. European Journal of Human Genetics, 2011, ⟨10.1038/ejhg.2011.120⟩. ⟨hal-00655429⟩