The broad phenotypic spectrum of PPP2R1A-related neurodevelopmental disorders correlates with the degree of biochemical dysfunction

Lisa Lenaerts, Sara Reynhout, Iris Verbinnen, Frederic Laumonnier, Annick Toutain, Frederique Bonnet-Brilhault, Yana Hoorne, Shelagh Joss, Anna K. Chassevent, Constance Smith-Hicks, Bart Loeys, Pascal Joset, Katharina Steindl, Anita Rauch, Sarju G. Mehta, Wendy K. Chung, Koenraad Devriendt, Susan E. Holder, Tamison Jewett, Lauren M. BaldwinWilliam G. Wilson, Shelley Towner, Siddharth Srivastava, Hannah F. Johnson, Cornelia Daumer-Haas, Martina Baethmann, Anna Ruiz, Elisabeth Gabau, Vani Jain, Vinod Varghese, Ali Al-Beshri, Stephen Fulton, Oded Wechsberg, Naama Orenstein, Katrina Prescott, Anne-Marie Childs, Laurence Faivre, Sebastien Moutton, Jennifer A. Sullivan, Vandana Shashi, Suzanne M. Koudijs, Malou Heijligers, Emma Kivuva, Amy McTague, Alison Male, Yvette van Ierland, Barbara Plecko, Isabelle Maystadt, Rizwan Hamid, Vickie L. Hannig, Gunnar Houge*, Veerle Janssens*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

9 Citations (Web of Science)

Abstract

Purpose Neurodevelopmental disorders (NDD) caused by protein phosphatase 2A (PP2A) dysfunction have mainly been associated with de novo variants in PPP2R5D and PPP2CA, and more rarely in PPP2R1A. Here, we aimed to better understand the latter by characterizing 30 individuals with de novo and often recurrent variants in this PP2A scaffolding A alpha subunit. Methods Most cases were identified through routine clinical diagnostics. Variants were biochemically characterized for phosphatase activity and interaction with other PP2A subunits. Results We describe 30 individuals with 16 different variants in PPP2R1A, 21 of whom had variants not previously reported. The severity of developmental delay ranged from mild learning problems to severe intellectual disability (ID) with or without epilepsy. Common features were language delay, hypotonia, and hypermobile joints. Macrocephaly was only seen in individuals without B55 alpha subunit-binding deficit, and these patients had less severe ID and no seizures. Biochemically more disruptive variants with impaired B55 alpha but increased striatin binding were associated with profound ID, epilepsy, corpus callosum hypoplasia, and sometimes microcephaly. Conclusion We significantly expand the phenotypic spectrum of PPP2R1A-related NDD, revealing a broader clinical presentation of the patients and that the functional consequences of the variants are more diverse than previously reported.

Original languageEnglish
Pages (from-to)352-362
Number of pages11
JournalGenetics in Medicine
Volume23
Issue number2
Early online date27 Oct 2020
DOIs
Publication statusPublished - Feb 2021

Keywords

  • PP2A
  • intellectual disability
  • neurodevelopmental disorder
  • epilepsy
  • PROTEIN PHOSPHATASE 2A
  • SUBUNIT
  • SPECIFICITY
  • PPP2R5D
  • DEPHOSPHORYLATION
  • INSIGHTS
  • FAMILY
  • CORE
  • TAU

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