EEF1B2 (eukaryotic translation elongation factor 1 beta 2) functions as the catalytic subunit of the guanine nucleotide exchange factor (GEF) within the eEF1 complex, stimulating GDP-GTP exchange on elongation factor 1A (eEF1A) to facilitate protein synthesis. The protein regulates cellular proliferation and apoptosis, particularly in human spermatogonial stem cells (SSCs), where EEF1B2 knockdown impairs proliferation, viability, and self-renewal through modulation of TAF4B signaling 1. Biallelic loss-of-function variants in EEF1B2 cause autosomal recessive intellectual disability with fever-sensitive seizures, as demonstrated by reduced mRNA and protein expression in affected patients and abnormal development in zebrafish models 2. The gene exhibits altered expression patterns across multiple cancer types, with overexpression associated with poor prognosis in specific breast and lung cancer subtypes 3. EEF1B2 represents one of several eEF1 complex subunits now recognized as causes of neurodevelopmental disorders, highlighting the critical role of translation elongation machinery in neuronal development 4. Additionally, alternative splicing generates novel protein isoforms with potentially distinct functions 5.