Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical activity in the brain. These episodes can result in physical injuries, either directly such as broken bones or through causing accidents. In epilepsy, seizures tend to recur and may have no immediate underlying cause. Isolated seizures that are provoked by a specific cause such as poisoning are not deemed to represent epilepsy. People with epilepsy may be treated differently in various areas of the world and experience varying degrees of social stigma due to the alarming nature of their symptoms.The underlying mechanism of epileptic seizures is excessive and abnormal neuronal activity in the cortex of the brain which can be observed in the electroencephalogram (EEG) of an individual. The reason this occurs in most cases of epilepsy is unknown (idiopathic); some cases occur as the result of brain injury, stroke, brain tumors, infections of the brain, or birth defects through a process known as epileptogenesis. Known genetic mutations are directly linked to a small proportion of cases. The diagnosis involves ruling out other conditions that might cause similar symptoms, such as fainting, and determining if another cause of seizures is present, such as alcohol withdrawal or electrolyte problems. This may be partly done by imaging the brain and performing blood tests.
Other close relatives of a person with epilepsy have a risk five times that of the general population. Between 1 and 10% of those with Down syndrome and 90% of those with Angelman syndrome have epilepsy. Phakomatoses
Phakomatoses, also known as neurocutaneous disorders, are a group of multisystemic diseases that most prominently affect the skin and central nervous system. They are caused by defective development of the embryonic ectodermal tissue that is most often due to a single genetic mutation. The brain, as well as other neural tissue and the skin, are all derived from the ectoderm and thus defective development may result in epilepsy as well as other manifestations such as autism and intellectual disability. Some types of phakomatoses such as tuberous sclerosis complex and Sturge-Weber syndrome have a higher prevalence of epilepsy relative to others such as neurofibromatosis type 1.Tuberous sclerosis complex is an autosomal dominant disorder that is caused by mutations in either the TSC1 or TSC2 gene and it affects approximately 1 in 6,000-10,000 live births. These mutations result in the upregulation of the mechanistic target of rapamycin (mTOR) pathway which leads to the growth of tumors in many organs including the brain, skin, heart, eyes and kidneys. In addition, abnormal mTOR activity is believed to alter neural excitability. The prevalence of epilepsy is estimated to be 80-90%. The majority of cases of epilepsy present within the first 3 years of life and are medically refractory. Relatively recent developments for the treatment of epilepsy in TSC patients include mTOR inhibitors, cannabidiol and vigabatrin.