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Updated: Aug 19, 2026

A Strategy to Identify de Novo Mutations in Common Disorders such as Autism and Schizophrenia
Published on: June 15, 2011
[Schizophrenia and ocular misalignment: phenotypic and genetic association analysis]
Y Yoshikawa1, T Toyota, K Yoshitsugu
1Laboratory for Molecular Psychiatry, RIKEN Brain Science Institute.
Abstract:
The increased incidence of minor physical anomalies (MPAs) in schizophrenia is the fundamental basis for the neurodevelopmental hypothesis of schizophrenia etiology. Ocular misalignment falls into the category of MPAs, but this phenotype has not been assessed in schizophrenia. This study reveals that constant exotropia displays marked association with schizophrenia. To assess the genetic mechanisms, we examined the transcription factor genes ARIX and its paralogue, PMX2B. We identified frequent deletion/insertion polymorphisms in the 20-alanine homopolymer stretch of PMX2B, with a modest association between these functional polymorphisms and constant exotropia in schizophrenia. The polymorphisms were also associated with overall schizophrenia and more specifically with schizophrenia manifesting strabismus. These results suggest a possible interaction between PMX2B and other schizophrenia-precipitating factors, increasing the risk of the combined phenotypes. This study also highlights the unique nature of the polyalanine length variations found in PMX2B.
Insights
Minor physical anomalies like constant exotropia are linked to schizophrenia. Gene variations in PMX2B show a modest association with schizophrenia and exotropia, suggesting a potential genetic interaction.
Area of Science:
- Neuroscience
- Genetics
- Psychiatry
Context:
- The neurodevelopmental hypothesis of schizophrenia etiology is supported by the increased incidence of minor physical anomalies (MPAs).
- Ocular misalignment, a type of MPA, has not been previously assessed in schizophrenia patients.
- Constant exotropia is identified as a phenotype significantly associated with schizophrenia.
Purpose:
- To investigate the association between constant exotropia and schizophrenia.
- To explore the genetic mechanisms underlying this association by examining transcription factor genes ARIX and PMX2B.
- To identify potential genetic risk factors and interactions contributing to schizophrenia and ocular misalignment.
Summary:
- This study found a marked association between constant exotropia and schizophrenia.
- Frequent deletion/insertion polymorphisms in the 20-alanine homopolymer stretch of PMX2B were identified.
- These PMX2B polymorphisms showed a modest association with constant exotropia in schizophrenia, overall schizophrenia, and schizophrenia with strabismus.
Impact:
- The findings suggest a possible interaction between PMX2B gene variations and other schizophrenia-precipitating factors, increasing the risk for combined phenotypes.
- This research highlights the unique nature of polyalanine length variations in PMX2B.
- The study provides novel insights into the genetic underpinnings of schizophrenia and its associated physical anomalies.
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