Rare coding variants in ten genes confer substantial risk for schizophrenia.

Area of Science:

• Neurogenetics
• Psychiatric Disorders

Background:

• Rare coding variation is key to understanding gene function and disease.
• Schizophrenia pathogenesis involves complex genetic factors.

Purpose of the Study:

• To identify ultra-rare coding variants (URVs) conferring substantial risk for schizophrenia.
• To explore the biological functions and pathways associated with schizophrenia risk genes.

Main Methods:

• Meta-analysis of whole-exome sequencing data from 24,248 schizophrenia cases and 97,322 controls.
• Statistical analysis to identify genes with URVs associated with schizophrenia risk (P < 2.14 × 10⁻⁶).

Main Results:

• Identified 10 genes with URVs conferring substantial schizophrenia risk (ORs 3-50) and 32 additional genes at a false discovery rate <5%.
• Associated genes show high expression in central nervous system neurons and are involved in synaptic formation, structure, and function.
• Found overlap in rare variant risk with autism spectrum disorders, epilepsy, and severe neurodevelopmental disorders.
• Demonstrated enrichment of rare variant risk in genes previously prioritized from common variant analyses, suggesting convergence of genetic risk factors.

Conclusions:

• Ultra-rare coding variants in specific genes represent significant risk factors for schizophrenia.
• Dysfunction of the glutamatergic system, supported by associations with GRIN2A and GRIA3, is a key mechanistic hypothesis.
• Schizophrenia shares genetic risk factors with other neurodevelopmental and neurological disorders, though distinct mutation types may be implicated.
• Both common and rare genetic variants contribute to schizophrenia risk, potentially converging on shared biological pathways.