Pisa syndrome is predominantly caused by a prolonged administration or an overly dosed administration of antipsychotic drugs. Although antipsychotic drugs are known to be the main drugs that are concerned with this syndrome, several other drugs are reported to have caused the syndrome as well. Certain antidepressants, psychoactive drugs, and antiemetics have also been found to cause Pisa syndrome in patients.

Drugs found to have caused Pisa Syndrome:

- Atypical antipsychotic drugs- ex. clozapine, aripiprazole

- Tricyclic antidepressants- ex. clomipramine

- Psychoactive drugs

- Antiemetic drugs

- Cholinesterase inhibitors

- Galantamine

Based on the drugs that caused Pisa syndrome, it has been implicated that the syndrome may be due to a dopaminergic-cholinergic imbalance or a serotonergic or noradrenergic dysfunction. For the development of Pisa syndrome that cannot be alleviated by anticholinergic drugs, it has been considered that asymmetric brain functions or neural transmission may be the underlying mechanism. How these drugs interact with the biochemistry of the brain to cause the syndrome is unknown and a topic of current research.

Anticholinergic drugs have been reported to be extremely effective in 40% of the patients with the Pisa syndrome. Patients with Pisa syndrome that is resistant to anticholinergic drugs is mostly resolved by the reduction of the administration of the antipsychotic drugs as previously mentioned. While the specific pathology underlying idiopathic Pisa syndrome is unknown, the administration of anticholinergic drugs has provided resolution in known cases.

It is not possible to make a generalised prognosis for development due to the variability of causes, as mentioned above, the differing types of symptoms and cause. Each case must be considered individually.

The prognosis for children with idiopathic West syndrome are mostly more positive than for those with the cryptogenic or symptomatic forms. Idiopathic cases are less likely to show signs of developmental problems before the attacks begin, the attacks can often be treated more easily and effectively and there is a lower relapse rate. Children with this form of the syndrome are less likely to go on to develop other forms of epilepsy; around two in every five children develop at the same rate as healthy children.

In other cases, however, treatment of West syndrome is relatively difficult and the results of therapy often dissatisfying; for children with symptomatic and cryptogenic West syndrome, the prognosis is generally not positive, especially when they prove resistant to therapy.

Statistically, 5 out of every 100 children with West syndrome do not survive beyond five years of age, in some cases due to the cause of the syndrome, in others for reasons related to their medication. Only less than half of all children can become entirely free from attacks with the help of medication. Statistics show that treatment produces a satisfactory result in around three out of ten cases, with only one in every 25 children's cognitive and motoric development developing more or less normally.

A large proportion (up to 90%) of children suffer severe physical and cognitive impairments, even when treatment for the attacks is successful. This is not usually because of the epileptic fits, but rather because of the causes behind them (cerebral anomalies or their location or degree of severity). Severe, frequent attacks can (further) damage the brain.

Permanent damage often associated with West syndrome in the literature include cognitive disabilities, learning difficulties and behavioural problems, cerebral palsy (up to 5 out of 10 children), psychological disorders and often autism (in around 3 out of 10 children). Once more, the cause of each individual case of West syndrome must be considered when debating cause and effect.

As many as 6 out of 10 children with West syndrome suffer from epilepsy later in life. Sometimes West syndrome turns into a focal or other generalised epilepsy. Around half of all children develop Lennox-Gastaut syndrome.

Incidence is around 1:3200 to 1:3500 of live births. Statistically, boys are more likely to be affected than girls at a ratio of around 1.3:1. In 9 out of every 10 children affected, the spasms appear for the first time between the third and the twelfth month of age. In rarer cases, spasms may occur in the first two months or during the second to fourth year of age.

Harlequin syndrome is not debilitating so treatment is not normally necessary. In cases where the individual may feel socially embarrassed, contralateral sympathectomy may be considered, although compensatory flushing and sweating of other parts of the body may occur. In contralateral sympathectomy, the nerve bundles that cause the flushing in the face are interrupted. This procedure causes both sides of the face to no longer flush or sweat. Since symptoms of Harlequin syndrome do not typically impair a person’s daily life, this treatment is only recommended if a person is very uncomfortable with the flushing and sweating associated with the syndrome.

One possible cause of Harlequin syndrome is a lesion to the preganglionic or postganglionic cervical sympathetic fibers and parasympathetic neurons of the ciliary ganglion. It is also believed that torsion (twisting) of the thoracic spine can cause blockage of the anterior radicular artery leading to Harlequin syndrome. The sympathetic deficit on the denervated side causes the flushing of the opposite side to appear more pronounced. It is unclear whether or not the response of the undamaged side was normal or excessive, but it is believed that it could be a result of the body attempting to compensate for the damaged side and maintain homeostasis.

Since the cause and mechanism of Harlequin syndrome is still unknown, there is no way to prevent this syndrome.

A syndrome is a set of medical signs and symptoms occurring together, constitutes a particular disease or disorder. The word derives from the Greek σύνδρομον, meaning "concurrence". In some instances, a syndrome is so closely linked with a pathogenesis or cause that the words "syndrome", "disease", and "disorder" end up being used interchangeably for them. This is especially true of inherited syndromes. For example, Down syndrome, Wolf–Hirschhorn syndrome, and Andersen syndrome are disorders with known pathogeneses, so each is more than just a set of signs and symptoms, despite the "syndrome" nomenclature. In other instances, a syndrome is not specific to only one disease. For example, toxic shock syndrome can be caused by various toxins; premotor syndrome can be caused by various brain lesions; and premenstrual syndrome is not a disease but simply a set of symptoms.

If an underlying genetic cause is suspected but not known, a condition may be referred to as a genetic association (often just "association" in context). By definition, an association indicates that the collection of signs and symptoms occurs in combination more frequently than would be likely by chance alone.

Syndromes are often named after the physician or group of physicians that discovered them or initially described the full clinical picture. Such eponymous syndrome names are examples of medical eponyms. Recently, there has been a shift towards naming conditions descriptively (by symptoms or underlying cause) rather than eponymously, but the eponymous syndrome names often persist in common usage.

In medicine a broad definition of syndrome is used, which describes a collection of symptoms and findings without necessarily tying them to a single identifiable pathogenesis. The more specific definition employed in medical genetics describes a subset of all medical syndromes.

Documented cases of Reye syndrome in adults are rare. The recovery of adults with the syndrome is generally complete, with liver and brain function returning to normal within two weeks of onset. In children, however, mild to severe permanent brain damage is possible, especially in infants. Over thirty percent of the cases reported in the United States from 1981 through 1997 resulted in fatality.

In the United States, sarcoidosis has a prevalence of approximately 10 cases per 100,000 whites and 36 cases per 100,000 blacks. Heerfordt syndrome is present in 4.1–5.6% of those with sarcoidosis.

Reye syndrome occurs almost exclusively in children. While a few adult cases have been reported over the years, these cases do not typically show permanent neural or liver damage. Unlike in the UK, the surveillance for Reye syndrome in the US is focused on patients under 18 years of age.

In 1980, after the CDC began cautioning physicians and parents about the association between Reye syndrome and the use of salicylates in children with chickenpox or virus-like illnesses, the incidence of Reye syndrome in the United States began to decline. However, the decline began prior to the FDA's issue of warning labels on aspirin in 1986. In the United States between 1980 and 1997, the number of reported cases of Reye syndrome decreased from 555 cases in 1980 to about 2 cases per year since 1994. During this time period 93% of reported cases for which racial data were available occurred in whites and the median age was six years. In 93% of cases a viral illness had occurred in the preceding three-week period. For the period 1991-1994, the annual rate of hospitalizations due to Reye syndrome in the US was estimated to be between 0.2 and 1.1 per million population less than 18 years of age.

During the 1980s, a case-control study carried out in the United Kingdom also demonstrated an association between Reye syndrome and aspirin exposure. In June 1986, the United Kingdom Committee on Safety of Medicines issued warnings against the use of aspirin in children under 12 years of age and warning labels on aspirin-containing medications were introduced. UK surveillance for Reye syndrome documented a decline in the incidence of the illness after 1986. The reported incidence rate of Reye syndrome decreased from a high of 0.63 per 100,000 population less than 12 years of age in 1983/84 to 0.11 in 1990/91.

From November 1995 to November 1996 in France, a national survey of pediatric departments for children under 15 years of age with unexplained encephalopathy and a threefold (or greater) increase in serum aminotransferase and/or ammonia led to the identification of nine definite cases of Reye syndrome (0.79 cases per million children). Eight of the nine children with Reye syndrome were found to have been exposed to aspirin. In part because of this survey result, the French Medicines Agency reinforced the international attention to the relationship between aspirin and Reye syndrome by issuing its own public and professional warnings about this relationship.

As the syndrome is due to a chromosomal non-disjunction event, the recurrence risk is not high compared to the general population. There has been no evidence found that indicates non-disjunction occurs more often in a particular family.

Respiratory complications are often cause of death in early infancy.

Males are twice as likely as females to have this characteristic, and it tends to run in families. In its non-symptomatic form, it is more common among Asians and Native Americans than among other populations, and in some families there is a tendency to inherit the condition unilaterally, that is, on one hand only.

The presence of a single transverse palmar crease can be, but is not always, a symptom associated with abnormal medical conditions, such as fetal alcohol syndrome, or with genetic chromosomal abnormalities, including Down Syndrome (chromosome 21), cri du chat syndrome (chromosome 5), Klinefelter syndrome, Wolf-Hirschhorn Syndrome, Noonan syndrome (chromosome 12), Patau syndrome (chromosome 13), IDIC 15/Dup15q (chromosome 15), Edward's syndrome (chromosome 18), and Aarskog-Scott syndrome (X-linked recessive), or autosomal recessive disorder, such as Leaukocyte adhesion deficiency-2 (LAD2). A unilateral single palmar crease was also reported in a case of chromosome 9 mutation causing Nevoid basal cell carcinoma syndrome and Robinow syndrome. It is also sometimes found on the hand of the affected side of patients with Poland Syndrome, and craniosynostosis.

Nevo Syndrome is considered to be a rare disorder. Since its first appearance in 1974, only a handful of cases have been reported. Studies have shown showing similarities between Nevo Syndrome with Ehlers-Danlos syndrome as well as Sotos syndrome. There is an astounding overlap of phenotypic manifestations between Nevo Syndrome and the more frequent Sotos syndrome, which are both caused by the NSD1 deletion. Sotos syndrome is an autosomal dominant condition associated with learning disabilities, a distinctive facial appearance, and overgrowth. Studies have shown an overwhelming occurrence (half of those involved in the study) of Nevo syndrome in those individuals of Middle-Eastern descent.

The prognosis varies widely from case to case, depending on the severity of the symptoms. However, almost all people reported with Aicardi syndrome to date have experienced developmental delay of a significant degree, typically resulting in mild to moderate to profound intellectual disability. The age range of the individuals reported with Aicardi syndrome is from birth to the mid 40s.

There is no cure for this syndrome.

The specific cause of camptodactyly remains unknown, but there are a few deficiencies that lead to the condition. A deficient lumbrical muscle controlling the flexion of the fingers, and abnormalities of the flexor and extensor tendons.

A number of congenital syndromes may also cause camptodactyly:

- Jacobsen syndrome

- Beals Syndrome

- Blau syndrome

- Freeman-Sheldon syndrome

- Cerebrohepatorenal syndrome

- Weaver syndrome

- Christian syndrome 1

- Gordon Syndrome

- Jacobs arthropathy-camptodactyly syndrome

- Lenz microphthalmia syndrome

- Marshall-Smith-Weaver syndrome

- Oculo-dento-digital syndrome

- Tel Hashomer camptodactyly syndrome

- Toriello-Carey syndrome

- Stuve-Wiedemann syndrome

- Loeys-Dietz syndrome

- Fryns syndrome

- Marfan's syndrome

- Carnio-carpo-tarsal dysthropy

In mild cases, individuals with XXXY syndrome may lead a relatively good life. These individuals may face difficulties in communicating with others due to their language-based deficits. These deficits may make forming bonds with others difficult, but fulfilling relationships with others are still achievable. Those with higher scores in adaptive functioning are likely to have higher quality of life because they can be independent.

Marshall–Smith syndrome is not to be confused with:

- Marshall syndrome (aka.Periodic fever, aphthous stomatitis, pharyngitis and adenitis (PFAPA syndrome, see also: Periodic fever syndrome)

- Sotos (like) syndrome

- Weaver-Smith syndrome (WSS)

Nevo Syndrome is an autosomal recessive disorder. Most times in which a child is afflicted with Nevo Syndrome, both their parents are of average height and weight. It is only until after birth when the characteristic physical traits associated with disease are manifested, and the disorder is actually diagnosed. One study showed that despite the increased growth rates, the patient was completely healthy up until age 6, when he was admitted into the hospital. Nevo syndrome is usually associated with early childhood fatality. Children with Nevo Syndrome have a high occurrence of death due to cardiac arrest because their developing hearts cannot keep up with their overgrown body.

Worldwide prevalence of Aicardi Syndrome is estimated at several thousand, with approximately 900 cases reported in the United States.

The pattern of inheritance is determined by the phenotypic expression of a gene—which is called "expressivity". Camptodactyly can be passed on through generations in various levels of phenotypic expression, which include both or only one hand. This means that the genetic expressivity is incomplete. It can be inherited from either parent.

In most of its cases, camptodactyly occurs sporadically, but it has been found in several studies that it is inherited as an autosomal dominant condition.

The Kocher–Debré–Semelaigne syndrome is hypothyroidism in infancy or childhood characterised by lower extremity or generalized muscular hypertrophy, myxoedema, short stature and cretinism. The absence of painful spasms and pseudomyotonia differentiates this syndrome from its adult form, which is Hoffmann syndrome.

The syndrome is named after Emil Theodor Kocher, Robert Debré and Georges Semelaigne.

Also known as Debre–Semelaigne syndrome or cretinism-muscular hypertrophy, hypothyroid myopathy, hypothyroidism-large muscle syndrome, hypothyreotic muscular hypertrophy in children, infantile myxoedema-muscular hypertrophy, myopathy-myxoedema syndrome, myxoedema-muscular hypertrophy syndrome, myxoedema-myotonic dystrophy syndrome.

Kocher-Debre-Semelaigne syndrome gives infant a Hercules appearance.

Roberts syndrome is an extremely rare condition that only affects about 150 reported individuals. Although there have been only about 150 reported cases, the affected group is quite diverse and spread worldwide. Parental consanguinity (parents are closely related) is common with this genetic disorder. The frequency of Roberts syndrome carriers is unknown.

There is considerable research into the causes, diagnosis and treatments for FGIDs. Diet, microbiome, genetics, neuromuscular function and immunological response all interact. Heightened mast cell activation has been proposed to be a common factor among FGIDs, contributing to visceral hypersensitivity as well as epithelial, neuromuscular, and motility dysfunction.