Homozygous ARHGEF2 mutation causes intellectual disability and midbrain-hindbrain malformation
Ethiraj Ravindran1,2,3, Hao Hu4,5, Scott A Yuzwa6,7
1Institute of Cell Biology and Neurobiology, Charité University Medicine Berlin, Berlin, Germany.
Plos Genetics
|April 29, 2017
Summary
A mutation in ARHGEF2 causes intellectual disability and midbrain-hindbrain malformations by disrupting progenitor cell differentiation and migration. This study identifies ARHGEF2 as crucial for human brain development.
Area of Science:
- Developmental Neuroscience
- Genetics
- Cell Biology
Background:
- Mid-hindbrain malformations arise from disrupted gene expression during embryogenesis.
- Rho guanine nucleotide exchange factor (ARHGEF) proteins regulate Rho GTPase signaling, impacting cell dynamics.
Purpose of the Study:
- To identify the genetic cause of intellectual disability and midbrain-hindbrain malformation in a consanguineous family.
- To elucidate the role of ARHGEF2 in human brain development and neurodevelopmental disorders.
Main Methods:
- Whole exome sequencing to identify causative mutations.
- In vitro studies on progenitor cell differentiation and migration.
- Analysis of RhoA/ROCK/MLC pathway activation.
- Generation and analysis of Arhgef2 mutant mouse models.
Main Results:
- A homozygous frameshift mutation in ARHGEF2 was identified as the cause of the observed neurodevelopmental disorder.
- Loss of ARHGEF2 function perturbs progenitor cell differentiation and mitotic spindle orientation.
- The mutation reduces RhoA/ROCK/MLC pathway activation, impairing cell migration.
- Arhgef2 mutant mice recapitulate the human brain malformation, showing aberrant migration of precerebellar system components.
Conclusions:
- ARHGEF2 plays a critical role in human brain development, particularly in regulating progenitor cell behavior.
- Mutations in ARHGEF2 represent a novel cause of neurodevelopmental disorders characterized by mid-hindbrain malformations.
- Aberrant cell migration is a key pathomechanism underlying ARHGEF2-associated brain malformations.
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