De Novo Truncating Mutations in the Last and Penultimate Exons of PPM1D Cause an Intellectual Disability Syndrome.

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ICR Authors

Lord, Christopher

Authors

Jansen, S
Geuer, S
Pfundt, R
Brough, R
Ghongane, P
Herkert, JC
Marco, EJ
Willemsen, MH
Kleefstra, T
Hannibal, M
Shieh, JT
Lynch, SA
Flinter, F
FitzPatrick, DR
Gardham, A
Bernhard, B
Ragge, N
Newbury-Ecob, R
Bernier, R
Kvarnung, M
Magnusson, EAH
Wessels, MW
van Slegtenhorst, MA
Monaghan, KG
de Vries, P
Veltman, JA
Deciphering Developmental Disorders Study,
Lord, CJ
Vissers, LELM
de Vries, BBA

Document Type

Journal Article

Date

2017-04-06

Date Accepted

2017-02-03

Abstract

Intellectual disability (ID) is a highly heterogeneous disorder involving at least 600 genes, yet a genetic diagnosis remains elusive in ∼35%-40% of individuals with moderate to severe ID. Recent meta-analyses statistically analyzing de novo mutations in >7,000 individuals with neurodevelopmental disorders highlighted mutations in PPM1D as a possible cause of ID. PPM1D is a type 2C phosphatase that functions as a negative regulator of cellular stress-response pathways by mediating a feedback loop of p38-p53 signaling, thereby contributing to growth inhibition and suppression of stress-induced apoptosis. We identified 14 individuals with mild to severe ID and/or developmental delay and de novo truncating PPM1D mutations. Additionally, deep phenotyping revealed overlapping behavioral problems (ASD, ADHD, and anxiety disorders), hypotonia, broad-based gait, facial dysmorphisms, and periods of fever and vomiting. PPM1D is expressed during fetal brain development and in the adult brain. All mutations were located in the last or penultimate exon, suggesting escape from nonsense-mediated mRNA decay. Both PPM1D expression analysis and cDNA sequencing in EBV LCLs of individuals support the presence of a stable truncated transcript, consistent with this hypothesis. Exposure of cells derived from individuals with PPM1D truncating mutations to ionizing radiation resulted in normal p53 activation, suggesting that p53 signaling is unaffected. However, a cell-growth disadvantage was observed, suggesting a possible effect on the stress-response pathway. Thus, we show that de novo truncating PPM1D mutations in the last and penultimate exons cause syndromic ID, which provides additional insight into the role of cell-cycle checkpoint genes in neurodevelopmental disorders.

Citation

American journal of human genetics, 2017, 100 (4), pp. 650 - 658

DOI

10.1016/j.ajhg.2017.02.005

URI

https://repository.icr.ac.uk/handle/internal/627

Rights

https://www.rioxx.net/licenses/all-rights-reserved

Source Title

Publisher

CELL PRESS

ISSN

0002-9297

eISSN

1537-6605

Collections

Breast Cancer Research
Cancer Biology

Research Team

Gene Function

Notes