Generalized myoclonic epilepsy with photosensitivity in juvenile dogs caused by a defective DIRAS family GTPase 1

Abstract

The clinical and electroencephalographic features of a canine generalized myoclonic epilepsy with photosensitivity and onset in young Rhodesian Ridgeback dogs (6 wk to 18 mo) are described. A fully penetrant recessive 4-bp deletion was identified in the DIRAS family GTPase 1 (DIRAS1) gene with an altered expression pattern of DIRAS1 protein in the affected brain. This neuronal DIRAS1 gene with a proposed role in cholinergic transmission provides not only a candidate for human myoclonic epilepsy but also insights into the disease etiology, while establishing a spontaneous model for future intervention studies and functional characterization.seizure | juvenile | canine | photosensitivity | Ras

Absence Seizures as a Feature of Juvenile Myoclonic Epilepsy in Rhodesian Ridgeback Dogs

“…A novel genetic myoclonic epilepsy in juvenile Rhodesian Ridgeback (RR) dogs, characterized by vigorous myoclonic seizures that occur mainly during relaxation periods, recently has been described . More than one‐third of affected dogs develop generalized tonic‐clonic seizures in the course of the disease, and 35% are reported to be photosensitive . The mean age of onset is 6 months (range, 6 weeks–1.5 years) .…”

“…More than one‐third of affected dogs develop generalized tonic‐clonic seizures in the course of the disease, and 35% are reported to be photosensitive . The mean age of onset is 6 months (range, 6 weeks–1.5 years) . Wireless video‐electroencephalography (EEG) in unsedated dogs was used as a tool to investigate the spontaneous and recurrent epileptic nature and to characterize the EEG features of the electroclinical syndrome .…”

“…The mean age of onset is 6 months (range, 6 weeks–1.5 years) . Wireless video‐electroencephalography (EEG) in unsedated dogs was used as a tool to investigate the spontaneous and recurrent epileptic nature and to characterize the EEG features of the electroclinical syndrome . Ambulatory video‐EEG confirmed the epileptic origin of the myoclonic twitches .…”

“…Wireless video‐electroencephalography (EEG) in unsedated dogs was used as a tool to investigate the spontaneous and recurrent epileptic nature and to characterize the EEG features of the electroclinical syndrome . Ambulatory video‐EEG confirmed the epileptic origin of the myoclonic twitches . Typically, affected dogs show generalized 4–5 Hz spike‐and‐wave complexes (SWC) and polyspike‐wave complexes (PSWC) with a fronto‐central maximum .…”

“…Typically, affected dogs show generalized 4–5 Hz spike‐and‐wave complexes (SWC) and polyspike‐wave complexes (PSWC) with a fronto‐central maximum . Genetic analyses identified a fully penetrant autosomal recessive 4‐bp truncating deletion mutation in the DIRAS1 gene, which is suggested to play a role in acetylcholine release …”