Onset is between 3 and 15 years of age with a mean of around 8. Both sexes are equally affected. The disorder accounts for about 2–7% of benign childhood focal seizures.

Jeavons syndrome is a lifelong disorder, even if seizures are well controlled with antiepileptic drugs. Men have a better prognosis than women. There is a tendency for photosensitivity to disappear in middle age, but eyelid myoclonia persists. It is highly resistant to treatment and occurs many times a day, often without apparent absences and even without demonstrable photosensitivity.

The prognosis of ICOE-G is unclear, although available data indicate that remission occurs in 50–60% of patients within 2–4 years of onset. Seizures show a dramatically good response to carbamazepine in more than 90% of patients. However, 40–50% of patients may continue to have visual seizures and infrequent secondarily generalized convulsions, particularly if they have not been appropriately treated with antiepileptic drugs.

The cause of ULD is known to be a mutation of the gene that produces cystatin B. The disease is autosomal recessive, so both parents of an individual must be carriers of the recessive CSTB gene for the individual to inherit it, and for an individual to show symptoms of ULD, they must have both recessive CSTB genes. Siblings of affected individuals who only have one recessive gene have been monitored and generally do not show the signs of ULD, though in some cases mild symptoms may be present.

The genetic cause of ULD is known, but research has led to new areas of study that may lead to an increase in knowledge of what causes ULD.

The most potent precipitating factor is eye closure, whether voluntary, involuntary or reflex. Most and, in some patients, all of the seizures are induced immediately after closure of the eyes in the presence of uninterrupted (non-flickering) light. Eye closure in total darkness is ineffective.

Contrary to other forms of photosensitive epilepsies that are sensitive only to flickering lights, patients with Jeavons syndrome are also sensitive to bright, non-flickering lights. This is probably due to the enhancing effect of bright light on the sensitivity of eye closure.

Duration of treatment is usually between 2 and 25 years. Earlier reports suggested that 90% of cases stay in remission after discontinuation of treatment; however, this is at odds with more recent studies which suggest that relapse commonly occurs after initial high-dose steroid treatment. Left untreated, this condition can result in coma and death.

When functioning correctly, mains-powered fluorescent lighting has a flicker rate sufficiently high (twice the mains frequency, typically 100 Hz or 120 Hz) to reduce the occurrence of problems. However, a faulty fluorescent lamp can flicker at a much lower rate and trigger seizures. Newer high-efficiency compact fluorescent lamps (CFL) with electronic ballast circuits operate at much higher frequencies (10–20 kHz) not normally perceivable by the human eye, though defective lights can still cause problems.

The Job Accommodation Network lists reduction or elimination of fluorescent lighting as an appropriate accommodation for many conditions including epilepsy. The Canadian Department of Labour states that the newer lights are problematic for fewer people.

The prevalence has been estimated to be 2.1/100,000 with a male to female ratio of 1:4. The mean age of onset is 44 with 20% of cases presenting before the age of 18 years. Most reported cases occur during the patient's fifth decade of life.

Television has traditionally been the most common source of seizures in PSE. For people with PSE, it is especially hazardous to view television in a dark room, at close range, or when the television is out of adjustment and is showing a rapidly flickering image (as when the horizontal hold is incorrectly adjusted). Modern digital television sets that cannot be maladjusted in this way and refresh the image on the screen at very high speed present less of a risk than older television sets.

Some people with PSE, especially children, may exhibit an uncontrollable fascination with television images that trigger seizures, to such an extent that it may be necessary to physically keep them away from television sets. Some people (particularly those with cognitive impairments, although most people with PSE have no such impairments) self-induce seizures by waving their fingers in front of their eyes in front of bright light or by other means.

Some UK television broadcasters and studios now screen content through the "Harding FPA Test", an objective standard of assessment of potential to trigger seizures in the susceptible population.

In some cases, specific television programs featuring certain types of visual stimuli have provoked seizures in a small minority of television viewers, including some viewers with no prior history of seizures of any kind. The "Dennō Senshi Porygon" episode of "Pokémon" is the most frequently cited example (see "the Society and culture section," below); when the program was broadcast in Japan, its strong flickering scenes produced seizures in a surprising number of viewers, even though the proportion of viewers affected was extremely low.

Nuclear factor-kappa B Essential Modulator (NEMO) deficiency syndrome is a rare type of primary immunodeficiency disease that has a highly variable set of symptoms and prognoses. It mainly affects the skin and immune system but has the potential to affect all parts of the body, including the lungs, urinary tract and gastrointestinal tract. It is a monogenetic disease caused by mutation in the IKBKG gene (IKKγ, also known as the NF-κB essential modulator, or NEMO). NEMO is the modulator protein in the IKK inhibitor complex that, when activated, phosphorylates the inhibitor of the NF-κB transcription factors allowing for the translocation of transcription factors into the nucleus.

The link between IKBKG mutations and NEMO deficiency was identified in 1999. IKBKG is located on the X chromosome and is X-linked therefore this disease predominantly affects males, However females may be genetic carriers of certain types of mutations. Other forms of the syndrome involving NEMO-related pathways can be passed on from parent to child in an autosomal dominant manner – this means that a child only has to inherit the faulty gene from one parent to develop the condition. This autosomal dominant type of NEMO deficiency syndrome can affect both boys and girls.

The Seckel syndrome or microcephalic primordial dwarfism (also known as bird-headed dwarfism, Harper's syndrome, Virchow-Seckel dwarfism, and Bird-headed dwarf of Seckel) is an extremely rare congenital nanosomic disorder.

Inheritance is autosomal recessive.

It is characterized by intrauterine growth retardation and postnatal dwarfism with a small head, narrow bird-like face with a beak-like nose, large eyes with down-slanting palpebral fissures , receding mandible and intellectual disability.

A mouse model has been developed. This mouse model is characterized by a severe deficiency of ATR protein. These mice suffer high levels of replicative stress and DNA damage. Adult Seckel mice display accelerated aging. These findings are consistent with the DNA damage theory of aging.

Congenital insensitivity to pain is found in Vittangi, a village in Kiruna Municipality in northern Sweden, where nearly 40 cases have been reported. A few Americans also have it.

It is supposed to be caused by defects of genes on chromosome 3 and 18. One form of Seckel syndrome can be caused by mutation in the gene encoding the ataxia telangiectasia and Rad3 related protein () which maps to chromosome 3q22.1-q24. This gene is central in the cell's DNA damage response and repair mechanism.

Types include:

Diagnosis

Originally NEMO deficiency syndrome was thought to be a combination of Ectodermal Dysplasia (ED) and a lack of immune function, but is now understood to be more complex disease. NEMO Deficiency Syndrome may manifest itself in the form of several different diseases dependent upon mutations of the IKBKG gene such as Incontinentia pigmenti or Ectodermal dysplasia.

The clinical presentation of NEMO deficiency is determined by three main symptoms:

1. Susceptibility to pyogenic infections in the form of severe local inflammation

2. Susceptibility to mycobacterial infection

3. Symptoms of Ectodermal Dysplasia

To determine whether or not patient has NEMO deficiency, an immunologic screen to test immune system response to antigen may be used although a genetic test is the only way to be certain as many individuals respond differently to the immunological tests.

Commonly Associated Diseases

NEMO deficiency syndrome may present itself as Incontinentia pigmenti or Ectodermal dysplasia depending on the type of genetic mutation present, such as if the mutation results in the complete loss of gene function or a point mutation.

Amorphic genetic mutations in the IKBKG gene, which result in the loss of gene function, typically present themselves as Incontinetia Pigmenti (IP). Because loss of NEMO function is lethal, only heterozygous females or males with XXY karyotype or mosaicism for this gene survive and exhibit symptoms of Incontinetia Pigmenti, such as skin lesions and abnormalities in hair, teeth, and nails. There are a variety of mutations that may cause the symptoms of IP, however, they all involve the deletion of exons on the IKBKG gene.

Hypomorphic genetic mutations in the IKBKG gene, resulting in a partial loss of gene function, cause the onset of Anhidrotic ectodermal dysplasia with Immunodeficiency (EDA-IP). The lack of NEMO results in a decreased levels of NF-κB transcription factor translocation and gene transcription, which in turn leads to a low level of immunoglobulin production. Because NF-κB translocation is unable to occur without proper NEMO function, the cell signaling response to immune mediators such as IL-1β, IL-18, and LPS are ineffective thus leading to a compromised immune response to various forms of bacterial infections.

Treatment

The aim of treatment is to prevent infections so children will usually be started on immunoglobulin treatment. Immunoglobulin is also known as IgG or antibody. It is a blood product and is given as replacement for people who are unable to make their own antibodies. It is the mainstay of treatment for patients affected by primary antibody deficiency. In addition to immunoglobulin treatment, children may need to take antibiotics or antifungal medicines to prevent infections or treat them promptly when they occur. Regular monitoring and check-ups will help to catch infections early. If an autoimmune response occurs, this can be treated with steroid and/or biologic medicines to damp down the immune system so relieving the symptoms.

In some severely affected patients, NEMO deficiency syndrome is treated using a bone marrow or blood stem cell transplant. The aim is to replace the faulty immune system with an immune system from a healthy donor.

The GM1 gangliosidoses (or GM1 gangliosidos"i"s) are caused by a deficiency of beta-galactosidase, with resulting abnormal storage of acidic lipid materials in cells of the central and peripheral nervous systems, but particularly in the nerve cells.

GM1 Gangliosidoses are inherited, autosomal recessive sphingolipidoses, resulting from marked deficiency of Acid Beta Galactosidase.

Cholinergic urticaria (CU) is a type of physical urticaria (or "hives") that appears when a person is sweating.

Hemicrania was mentioned in 1881 in The Therapeutic Gazette Vol. 2, by G.S.Davis, and the incident has been cited in King's American Dispensatory (1898 and later editions) in the description of the strong analgesic Jamaican Dogwood, a relatively low dose of which reportedly produced convulsions and prolonged respiratory depression over six hours in an elderly woman with this condition.

In newer times, Hemicrania continua was described in 1981; at that time around 130 cases were described in the literature. However, rising awareness of the condition has led to increasingly frequent diagnosis in headache clinics, and it seems that it is not as rare as these figures would imply. The condition occurs more often in women than men and tends to present first in adulthood, although it has also been reported in children as young as 5 years old.

Minimal change disease is most common in very young children but can occur in older children and adults. It is by far the most common cause of nephrotic syndrome in children between the ages of 1 and 7, accounting for the majority (about 90%) of these diagnoses. Among teenagers who develop nephrotic syndrome, it is caused by minimal change disease about half the time. It can also occur in adults but accounts for less than 20% of adults diagnosed with nephrotic syndrome. Among children less than 10 years of age, boys seem to be more likely to develop minimal change disease than girls. Minimal change disease is being seen with increasing frequency in adults over the age of 80.

People with one or more autoimmune disorders are at increased risk of developing minimal change disease. Having minimal change disease also increases the chances of developing other autoimmune disorders.

Onset of adult GM1 is between ages 3 and 30.

Symptoms include muscle atrophy, neurological complications that are less severe and progress at a slower rate than in other forms of the disorder, corneal clouding in some patients, and dystonia (sustained muscle contractions that cause twisting and repetitive movements or abnormal postures). Angiokeratomas may develop on the lower part of the trunk of the body. Most patients have a normal size liver and spleen.

Prenatal diagnosis is possible by measurement of Acid Beta Galactosidase in cultured amniotic cells.

The opioid antagonist naloxone allowed a woman with congenital insensitivity to pain to experience it for the first time. Similar effects were observed in Na1.7 null mice treated with naloxone. As such, opioid antagonists like naloxone and naltrexone may be effective in treating the condition.

The cause of hemicrania continua is unknown. There is no definitive diagnostic test for hemicrania continua. Diagnostic tests such as imaging studies may be ordered to rule out other causes for the headache. When the symptoms of hemicrania continua are present, it's considered "diagnostic" if they respond completely to indomethacin. The efficacy of indomethacin may not be long term for all patients, as can eventually become ineffective.

The factor that allows hemicrania continua and its exacerbations to be differentiated from migraine and cluster headache is that hemicrania continua is completely responsive to indomethacin. Triptans and other abortive medications do not affect hemicrania continua.

One of the defining characteristics of minimally conscious state is the more continuous improvement and significantly more favorable outcomes post injury when compared with vegetative state. One study looked at 100 patients with severe brain injury. At the beginning of the study, all the patients were unable to follow commands consistently or communicate reliably. These patients were diagnosed with either MCS or vegetative state based on performance on the JFK Coma Recovery Scale and the diagnostic criteria for MCS as recommended by the Aspen Consensus Conference Work-group. Both patient groups were further separated into those that suffered from traumatic brain injury and those that suffered from non-traumatic brain injures (anoxia, tumor, hydrocephalus, infection). The patients were assessed multiple times over a period of 12 months post injury using the Disability Rating Scale (DRS) which ranges from a score of 30=dead to 0=no disabilities. The results show that the DRS scores for the MCS subgroups showed the most improvement and predicted the most favorable outcomes 12 months post injury. Amongst those diagnosed with MCS, DRS scores were significantly lower for those with non-traumatic brain injuries in comparison to the vegetative state patients with traumatic brain injury. DRS scores were also significantly lower for the MCS non-traumatic brain injury group compared to the MCS traumatic brain injury group. Pairwise comparisons showed that DRS scores were significantly higher for those that suffered from non-tramuatic brain injuries than those with traumatic brain injuries. For the patients in vegetative states there were no significant differences between patients with non-traumatic brain injury and those with traumatic brain injuries. Out of the 100 patients studied, 3 patients fully recovered (had a DRS score of 0). These 3 patients were diagnosed with MCS and had suffered from traumatic brain injuries.

In summary, those with minimally conscious state and non-traumatic brain injuries will not progress as well as those with traumatic brain injuries while those in vegetative states have an all around lower to minimal chance of recovery.

Because of the major differences in prognosis described in this study, this makes it crucial that MCS be diagnosed correctly. Incorrectly diagnosing MCS as vegetative state may lead to serious repercussions related to clinical management.

Minimal change disease has been called by many other names in the medical literature, including minimal change nephropathy, minimal change nephrosis, minimal change nephrotic syndrome, minimal change glomerulopathy, foot process disease (referring to the foot processes of the podocytes), nil disease (referring to the lack of pathologic findings on light microscopy), nil lesions, lipid nephrosis, and lipoid nephrosis.

CU typically presents with a number of small, short-lasting hives but may also involve cutaneous inflammation (wheals) and pain which develops usually in response to exercise, bathing, staying in a heated environment, or emotional stress. Although the symptoms subside rapidly, commonly within 1 hour, CU may significantly impair quality of life, especially in relation to sporting activities.