A case series of familial ARID1B variants illustrating variable expression and suggestions to update the ACMG criteria

Pleuntje J. van der Sluijs, Mariëlle Alders, Alexander J.M. Dingemans, Kareesma Parbhoo, Bregje W. van Bon, Jennifer C. Dempsey, Dan Doherty, Johan T. Den Dunnen, Erica H. Gerkes, Ilana M. Milller, Stephanie Moortgat, Debra S. Regier, Claudia A.L. Ruivenkamp, Betsy Schmalz, Thomas Smol, Kyra E. Stuurman, Catherine Vincent-Delorme, Bert B.A. de Vries, Bekim Sadikovic, Scott E. HickeyJill A. Rosenfeld, Isabelle Maystadt, Gijs W.E. Santen*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Scopus)
13 Downloads (Pure)


ARID1B is one of the most frequently mutated genes in intellectual disability (~1%). Most variants are readily classified, since they are de novo and are predicted to lead to loss of function, and therefore classified as pathogenic according to the American College of Medical Genetics and Genomics (ACMG) guidelines for the interpretation of sequence variants. However, familial loss-of-function variants can also occur and can be challenging to interpret. Such variants may be pathogenic with variable expression, causing only a mild phenotype in a parent. Alternatively, since some regions of the ARID1B gene seem to be lacking pathogenic variants, loss-of-function variants in those regions may not lead to ARID1B haploinsufficiency and may therefore be benign. We describe 12 families with potential loss-of-function variants, which were either familial or with unknown inheritance and were in regions where pathogenic variants have not been described or are otherwise challenging to interpret. We performed detailed clinical and DNA methylation studies, which allowed us to confidently classify most variants. In five families we observed transmission of pathogenic variants, confirming their highly variable expression. Our findings provide further evidence for an alternative translational start site and we suggest updates for the ACMG guidelines for the interpretation of sequence variants to incorporate DNA methylation studies and facial analyses.

Original languageEnglish
Article number1275
Issue number8
Publication statusPublished - 20 Aug 2021


Dive into the research topics of 'A case series of familial ARID1B variants illustrating variable expression and suggestions to update the ACMG criteria'. Together they form a unique fingerprint.

Cite this