An Integrated Phenotypic and Genotypic Approach Reveals a High-Risk Subtype Association for EBF3 Missense Variants...

Area of Science:

• Neurogenetics
• Developmental Neuroscience

Background:

• Collier/Olf/EBF (COE) transcription factors play crucial roles in nervous system development.
• Early B-cell Factor-3 (EBF3) is the only COE member with a confirmed link to autism spectrum/neurodevelopmental disorders (NDD) via loss-of-function variants.

Purpose of the Study:

• To investigate the association between EBF3 variant type and location and symptom severity in EBF3-related NDD.
• To establish genotype-phenotype correlations for EBF3 variants.

Main Methods:

• Phenotypic assessment of 41 individuals with EBF3-related NDD, combined with a literature meta-analysis of 83 individuals.
• Development of quantitative diagnostic phenotypic and symptom severity scales.
• In vivo (Drosophila melanogaster) and in vitro assays to assess the functional impact of EBF3 variants on the DNA-binding domain (DBD) and zinc finger (ZNF) domains.

Main Results:

• Patient symptom severity correlates with EBF3 missense variants that disrupt the ZNF domain, essential for DNA binding.
• ZNF-associated variants impaired transcriptional activation and failed to restore viability in a fruit fly model.
• A recurrent variant in the DBD (EBF3 p.Arg209Trp) showed partial rescue of viability and preserved transcriptional activation.

Conclusions:

• A significant association exists between ZNF perturbations in EBF3 and increased symptom severity in NDD patients.
• This genotype-phenotype correlation offers potential predictive clinical value for individuals with newly identified EBF3 variants.