Primary Generalized Epilepsy in Omani patients: clinical characteristics, inheritance pattern, electrophysiological abnormalities, treatment response and frequency of sleep apnea syndrome

Primary Generalized Epilepsy (PGE), also called Idiopathic Generalized Epilepsy (IGE), refers to an epileptic syndrome with seizure activity arising from both sides of the brain regions simultaneously of presumably idiopathic or unknown cause. IGEs constitute about 15-20% of all epilepsies. They affect otherwise normal people of both sexes and all races. Patients with IGE have one or more of three types of (primary generalized) seizures: myoclonic, absence and generalized tonic-clonic seizures. There are number of recognized syndromes based on the combination of these seizure types, circadian occurrence, severity, frequency, age of onset, cognitive impairment and familial features. The electroencephalogram (EEG) is the one of the most useful investigations that aids in the diagnosis of IGE. The EEG findings in these patients are variable and include generalized spikes, polyspikes or spike/polyspike. Increasingly, many of these epileptic syndromes have been observed to have a genetic basis (for instance, mutation of cell membrane-bound ion channels). In fact, in recent years many advances have been made in understanding the underlying andldquo;complexandrdquo; genetic abnormalities in some of these syndromes. Advances in understanding of the underlying genetic disorders will further enhance our knowledge about the pathophysiological basis of these syndromes and will aid in genetic counseling and treatment. Patients with IGE are more prone to develop seizures if they are sleep deprived. In other words, sleep deprivation would lower seizure threshold and could precipitate seizures in these patients. In Oman, sleep disturbances related to obstructive sleep apnea is quite common, as obesity, a risk marker of sleep apnea is emerging as a looming epidemic . There are a number of useful questionnaires that have been developed and validated to assess the degree of sleepiness- in particular to screen patients suspected to have sleep apnea. The standard ones that are used in sleep research include Berlin and Epworth Sleepiness Scale. This study has two components. The first component is a retrospective study of the clinical and electrophysiological profiles of these patients with IGE who were seen in SQUH from 1 st of January 2007 till 31 st of December 2011. The second component is a prospective study where all patients who fulfill the criteria of IGE and consent to participate in the study will be recruited. Their clinical and EEG profiles will be assessed and screened for sleep apnea by the standard questionnaires. Their clinical response to anticonvulsant therapy will be assessed during the project period. Blood samples from the consenting patients and their healthy and affected relatives will be drawn for DNA banking for future genetic study.