N-methyl-D-aspartate receptors are essential glutamate receptors in the brain, encoded by seven different genes
(denoted GRIN). Recently, we described two de novo mutations in GRIN2B that severely affect channel
function and expression and, consequently, instigate a devastating neurodevelopmental disorder; without a
cure1,2. These join the list of thousands of pathogenic mutations newly identified in all GRINs. In ~35% of the
cases, de novo nonsense mutations give rise to haploinsufficiency leading to the protein being expressed at
only ~half its normal levels, while remaining cases consist of missense variants that severely affect channel
activity and/or expression. We anticipated that both could be addressed via genetic reintroduction of the
corresponding wildtype gene. This would remedy cases of haploinsufficiency, as well as mitigate the impact of
missense mutations by providing wt subunits to compete and dilute the variant’s effect. To reintroduce the wt
gene, we focus on BBB-crossing Adeno-Associated Viruses (AAVBBB) for gene-delivery. We demonstrate
successful packaging of GRIN2B gene (longest of all GRINs) into AAVBBB by using short- and mini-promoters.
We then demonstrate expression of the subunit following AAV-infection of primary neurons in vitro and—in
vivo—in mouse brains following tail-vein injections. We propose to explore the functional rescue of the disease
by viral-delivery of GRIN2B in two unique Grin2B-animal models. Importantly, we intend to rapidly develop
similar treatments for all other GRINs. Together, our proposal is innovative and unexplored, and presents
unequivocal evidence for feasibility. We suggest that it should lead to a genetic treatments for all glutamate
channel-related diseases.