Biallelic BECN1 variants cause neurodevelopmental disorders via AMPA receptor dysregulation

Genetic regulation of neurodevelopmental disorders that impair brain development and social interaction is complex and poorly understood. Although emerging evidence suggests a link between neurodevelopmental disorders and autophagy deficits, congenital autophagy gene disorders are rare in humans, and underlying molecular mechanisms remain unknown. Here we demonstrate that the autophagy protein BECN1 is a regulator of neuronal and social development in vertebrate species. We identify rare deleterious biallelic BECN1 variants that cause neurodevelopmental disorders in two unrelated families. Becn1 disruption also causes neuronal and social developmental defects in mouse and zebrafish models. BECN1 serves as an adaptor to recruit Arc to the E3 ubiquitin ligase UBE3A for polyubiquitination and degradation, thereby maintaining postsynaptic AMPA receptor (AMPAR) stability, AMPAR-mediated excitatory neurotransmission, and normal social interaction. Thus, our study illustrates new biology and a non-canonical mechanism by which BECN1 regulates neurodevelopment in humans, mice and zebrafish, via a crosstalk with the ubiquitin-proteasomal machinery.