Background: SLC13A5 Citrate Transporter Disorder is a rare pediatric neurodevelopmental disorder. Patients have epilepsy, developmental disability, and impaired mobility. While sleep disorders are common in children with neurodevelopmental disorders, sleep abnormalities have not been reported in SLC13A5 patients. Methods: Here, we assessed sleep disturbances in patients through caregiver reported surveys and in a transgenic mouse model of SLC13A5 deficiency. A total of 26 patients were evaluated with the Sleep Disturbance Scale for Children three times over a one-year span. Sleep and wake activities were assessed in the SLC13A5 knock-out (KO) mice using wireless telemetry devices. Results: A high burden of clinically significant sleep disturbances were reported in the patients, with heterogeneous symptoms that remained stable across time. While sleep disturbances were common, less than 30% of patients were prescribed medications for sleep. Comparatively, in SLC13A5 KO mice using EEG recordings, significant alterations were found during light cycles, when rodents typically sleep. During the sleep period, SLC13A5 mice had increased activity, decreased paradoxical sleep, and changes in absolute power spectral density, indicating altered sleep architecture in the mouse model. Conclusions: Our results demonstrate a significant component of sleep disturbances in SLC13A5 patients and mice, highlighting a potential gap in patient care. Further investigation of sleep dysfunction and the underlying etiologies of sleep disturbances in SLC13A5 citrate transporter disorder is warranted.

SLC13A5 citrate transporter disorder is a rare epileptic encephalopathy caused by loss-of-function pathogenic variants in the SLC13A5 gene. Loss of sodium/citrate cotransporter (NaCT) function causes a severe early-life epilepsy resulting in lifelong developmental disabilities and increased extracellular citrate. Current antiseizure medications may reduce seizure frequency, yet more targeted treatments are needed to address the epileptic and neurodevelopmental SLC13A5 phenotype. We performed preclinical studies in SLC13A5-deficient (KO) mice evaluating phenotype rescue with adeno-associated virus (AAV) vector carrying a functional copy of the human SLC13A5 gene (AAV9/SLC13A5). Cerebrospinal fluid delivery of AAV9/SLC13A5 decreased extracellular citrate levels, normalized electrophysiologic and sleep architecture abnormalities, and restored resistance to chemically induced seizures and death. Treatment benefits were achieved with administration during early brain development and in young adult mice, indicating therapeutic efficacy across developmental and postdevelopmental stages. Comparison of delivery routes in young adult KO mice showed that higher brain targeting achieved with intra–cisterna magna delivery resulted in greater treatment benefit as compared with intrathecal lumbar puncture delivery. Together, these results support further development of AAV9/SLC13A5 for treating SLC13A5 citrate transporter disorder.