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Abstract Objectives The main goal of presurgical evaluation in drug‐resistant focal epilepsy is to identify a seizure onset zone (SOZ). Of the noninvasive, yet resource‐intensive tests available, ictal single‐photon emission computed tomography (SPECT) aids SOZ localization by measuring focal increases in blood flow within the SOZ via intravenous peri‐ictal radionuclide administration. Recent studies indicate that geographic and center‐specific factors impact utilization of these diagnostic procedures. Our study analyzed successful ictal SPECT acquisition (defined as peri‐ictal injection during inpatient admission) using surgery‐related data from the Pediatric Epilepsy Research Consortium (PERC) surgery database. We hypothesized that a high seizure burden, longer duration of video EEG monitoring (VEEG), and more center‐specific hours of SPECT availability would increase the likelihood of successful ictal SPECT. Methods We identified study participants (≤18 years of age) who underwent SPECT as part of their phase 1 VEEG from January 2018 to June 2022. We assessed association between ictal SPECT outcomes (success vs. failure) and variables including patient demographics, epilepsy history, and center‐specific SPECT practices. Results Phase 1 VEEG monitoring with ictal SPECT injection was planned in 297 participants and successful in 255 participants (85.86%). On multivariable analysis, the likelihood of a successful SPECT injection was higher in patients of non‐Hispanic ethnicity (p = 0.040), shorter duration VEEG (p = 0.004), and higher hours of available SPECT services (p

Abstract Objective Genetic variants in the GRIN genes that encode N‐methyl‐D‐aspartate receptor (NMDAR) subunits have been identified in various neurodevelopmental disorders, including epilepsy. We identified a GRIN1 variant from an individual with early‐onset epileptic encephalopathy, evaluated functional changes to NMDAR properties caused by the variant, and screened FDA‐approved therapeutic compounds as potential treatments for the patient. Methods Whole exome sequencing identified a missense variant in GRIN1. Electrophysiological recordings were made from Xenopus oocytes and transfected HEK cells to determine the NMDAR biophysical properties as well as the sensitivity to agonists and FDA‐approved drugs that inhibit NMDARs. A beta‐lactamase reporter assay in transfected HEK cells evaluated the effects of the variant on the NMDAR surface expression. Results A recurrent de novo missense variant in GRIN1 (c.1923G>A, p.Met641Ile), which encodes the GluN1 subunit, was identified in a pediatric patient with drug‐resistant seizures and early‐onset epileptic encephalopathy. In vitro analysis indicates that GluN1‐M641I containing NMDARs showed enhanced agonist potency and reduced Mg2+ block, which may be associated with the patient’s phenotype. Results from screening FDA‐approved drugs suggested that GluN1‐M641I containing NMDARs are more sensitive to the NMDAR channel blockers memantine, ketamine, and dextromethorphan compared to the wild‐type receptors. The addition of memantine to the seizure treatment regimen significantly reduced the patient’s seizure burden. Interpretation Our finding contributes to the understanding of the phenotype–genotype correlations of patients with GRIN1 gene variants, provides a molecular mechanism underlying the actions of this variant, and explores therapeutic strategies for treating GRIN1‐related neurological conditions.