The cause of Primrose syndrome is currently unknown. This condition is extremely rare and seems to spontaneously occur, regardless of family history.

In the case studied by Dalai et al. in 2010, it was found that an abnormally high amount of calcitonin, a hormone secreted by the thyroid gland to stabilize blood calcium levels, was present in the blood serum. This suggests that the thyroid gland is releasing an abnormal amount of calcitonin, resulting in the disruption of calcium level homeostasis. No molecular cause was found, but an expanded microarray analysis of the patient found a 225.5 kb deletion on chromosome 11p between rs12275693 and rs1442927. Whether or not this deletion is related to the syndrome or is a harmless mutation is unknown. The deletion was not present in the patient's mother's DNA sample, but the father's DNA was unavailable.

Primrose syndrome is a rare, slowly progressive genetic disorder that can vary symptomatically between individual cases, but is generally characterised by ossification of the external ears, learning difficulties, and facial abnormalities. It was first described in 1982 in Scotland's Royal National Larbert Institution by Dr D.A.A. Primrose.

Primrose syndrome appears to occur spontaneously, regardless of family history. The cause is currently unknown and there are no known treatments.

The prognosis for individuals with severe LNS is poor. Death is usually due to renal failure or complications from hypotonia, in the first or second decade of life. Less severe forms have better prognoses.

There is no standard treatment for hydranencephaly. Treatment is symptomatic and supportive. Hydrocephalus may be treated with surgical treatment of a shunt, which often grants a much better prognosis and greater quality of life.

The prognosis for children with hydranencephaly is generally quite poor. Death often occurs in the first year of life, but other children may live several years.

Medical text identifies that hydranencephalic children simply have only their brain stem function remaining, thus leaving formal treatment options as symptomatic and supportive. Severe hydrocephalus causing macrocephaly, a larger than average head circumference, can easily be managed by placement of a shunt and often displays a misdiagnosis of another lesser variation of cephalic condition due to the blanketing nature of hydrocephalus. Plagiocephaly, the asymmetrical distortion of the skull, is another typical associated condition that is easily managed through positioning and strengthening exercises to prevent torticollis, a constant spasm or extreme tightening of the neck muscles.

Treatment for LNS is symptomatic. Gout can be treated with allopurinol to control excessive amounts of uric acid. Kidney stones may be treated with lithotripsy, a technique for breaking up kidney stones using shock waves or laser beams. There is no standard treatment for the neurological symptoms of LNS. Some may be relieved with the drugs carbidopa/levodopa, diazepam, phenobarbital, or haloperidol.

It is essential that the overproduction of uric acid be controlled in order to reduce the risk of nephropathy, nephrolithiasis, and gouty arthritis. The drug allopurinol is utilized to stop the conversion of oxypurines into uric acid, and prevent the development of subsequent arthritic tophi (produced after having chronic gout), kidney stones, and nephropathy, the resulting kidney disease. Allopurinol is taken orally, at a typical dose of 3–20 mg/kg per day. The dose is then adjusted to bring the uric acid level down into the normal range (<3 mg/dL). Most affected individuals can be treated with allopurinol all through life.

No medication is effective in controlling the extrapyramidal motor features of the disease. Spasticity, however, can be reduced by the administration of baclofen or benzodiazepines.

There has previously been no effective method of treatment for the neurobehavioral aspects of the disease. Even children treated from birth with allopurinol develop behavioral and neurologic problems, despite never having had high serum concentrations of uric acid. Self-injurious and other behaviors are best managed by a combination of medical, physical, and behavioral interventions. The self-mutilation is often reduced by using restraints. Sixty percent of individuals have their teeth extracted in order to avoid self-injury, which families have found to be an effective management technique. Because stress increases self-injury, behavioral management through aversive techniques (which would normally reduce self-injury) actually increases self-injury in individuals with LNS. Nearly all affected individuals need restraints to prevent self-injury, and are restrained more than 75% of the time. This is often at their own request, and occasionally involves restraints that would appear to be ineffective, as they do not physically prevent biting. Families report that affected individuals are more at ease when restrained.

The Matheny Medical and Educational Center in Peapack, NJ, has nine Lesch–Nyhan syndrome patients, believed to be the largest concentration of LNS cases in one location, and is recognized as the leading source of information on care issues.

Treatment for LNS patients, according to Gary E. Eddey, MD, medical director, should include: 1) Judicious use of protective devices; 2) Utilization of a behavioral technique commonly referred to as 'selective ignoring' with redirection of activities; and 3) Occasional use of medications.

An article in the August 13, 2007 issue of "The New Yorker" magazine, written by Richard Preston, discusses "deep-brain stimulation" as a possible treatment. It has been performed on a few patients with Lesch–Nyhan syndrome by Dr. Takaomi Taira in Tokyo and by a group in France led by Dr. Philippe Coubes. Some patients experienced a decrease in spastic self-injurious symptoms. The technique was developed for treating people with Parkinson's disease, according to Preston, over 20 years ago. The treatment involves invasive surgery to place wires that carry a continuous electric current into a specific region of the brain.

An encouraging advance in the treatment of the neurobehavioural aspects of LNS was the publication in the October, 2006 issue of "Journal of Inherited Metabolic Disease" of an experimental therapy giving oral S-adenosyl-methionine (SAMe).

This drug is a nucleotide precursor that provides a readily absorbed purine, which is known to be transported across the blood–brain barrier. Administration of SAMe to adult LNS patients was shown to provide improvement in neurobehavioural and other neurological attributes. The drug is available without prescription and has been widely used for depression, but its use for treating LNS should be undertaken only under strict medical supervision, as side effects are known.

SAMe has also been used recently to treat another purine nucleotide disease, "Art's syndrome" (which is a PRPP disorder in common with LNS), with encouraging results.

Thus SAMe may be useful for treating purine nucleotide diseases, which include LNS.

This condition possesses isolated occurrences, affecting less than 1 in 10,000 births worldwide and officially classifying hydranencephaly as a rare disorder by affecting fewer than 1 in 250,000 in the United States.

Response to treatment is variable and the long-term and functional outcome is unknown. To provide a basis for improving the understanding of the epidemiology, genotype/phenotype correlation and outcome of these diseases their impact on the quality of life of patients, and for evaluating diagnostic and therapeutic strategies a patient registry was established by the noncommercial International Working Group on Neurotransmitter Related Disorders (iNTD).

In those with SS, symptoms typically dramatically improve with low-dose administration of levodopa (L-dopa). L-DOPA exists as a biochemically significant metabolite of the amino acid phenylalanine, as well as a biological precursor of the catecholamine dopamine, a neurotransmitter. (Neurotransmitters are naturally produced molecules that may be sequestered following the propagation of an action potential down a nerve towards the axon terminal, which in turn may cross the synaptic junction between neurons, enabling neurons to communicate in a variety of ways.) Low-dose L-dopa usually results in near-complete or total reversal of all associated symptoms for these patients. In addition, the effectiveness of such therapy is typically long term, without the complications that often occur for those with Parkinson's disease who undergo L-dopa treatment. Thus, most experts indicate that this disorder is most appropriately known as dopa-responsive dystonia (SS).

No data are available on mortality associated with SS, but patients surviving beyond the fifth decade with treatment have been reported. However, in severe, early autosomal recessive forms of the disease, patients have been known to pass away during childhood. Girls seem to be somewhat more commonly affected. The disease less commonly begins during puberty or after age 20, and very rarely, cases in older adults have been reported.

Due to commonly being misdiagnosed, it is common for the disease to remain untreated. When left untreated, patients often need achilles tendon surgery by the age of 21. They will also struggle with walking, an ability that will degrade throughout the day. Power napping can provide temporary relief in untreated patients. It also impairs development into adulthood, reduces balance, and reduces calf muscle development. Socially, it can result in depression, lack of social skills, and inability to find employment.

Succinic acid has been studied, and shown effective for both Leighs disease, and MELAS syndrome. If the mutation is in succinate dehydrogenase then there is a build up of succinate, in which case succinic acid won't work so the treatment is with fumaric acid to replace the fumarate than can not be made from succinate. A high-fat, low-carbohydrate diet may be followed if a gene on the X chromosome is implicated in an individual's Leigh syndrome. Thiamine (vitamin B) may be given if a deficiency of pyruvate dehydrogenase is known or suspected. The symptoms of lactic acidosis are treated by supplementing the diet with sodium bicarbonate (baking soda) or sodium citrate, but these substances do not treat the cause of Leigh syndrome. Dichloroacetate may also be effective in treating Leigh syndrome-associated lactic acidosis; research is ongoing on this substance. Coenzyme Q10 supplements have been seen to improve symptoms in some cases.

Clinical trials of the drug EPI-743 for Leigh disease are ongoing.

In 2016, John Zhang and his team at New Hope Fertility Center in New York, USA, performed a spindle transfer mitochondrial donation technique on a mother in Mexico who was at risk of producing a baby with Leigh disease. A healthy boy was born on 6 April 2016. However, it is not yet certain if the technique is completely reliable and safe.

Different genetic causes and types of Leigh syndrome have different prognoses, though all are poor. The most severe forms of the disease, caused by a full deficiency in one of the affected proteins, cause death at a few years of age. If the deficiency is not complete, the prognosis is somewhat better and an affected child is expected to survive 6–7 years, and in rare cases, to their teenage years.

Drug treatment is indicated for patients with severe disabling chorea. It is treated with haloperidol, chlorpromazine alone or in combination with diazepam, and also pimozide, which is another neuroleptic drug which may have fewer adverse effects than haloperidol. Valproic acid, chloral hydrate, risperidone, or phenobarbital can also be used.

No specific treatment is known that would prevent, slow, or reverse HSP. Available therapies mainly consist of symptomatic medical management and promoting physical and emotional well-being. Therapeutics offered to HSP patients include:

- Baclofen – a voluntary muscle relaxant to relax muscles and reduce tone. This can be administered orally or intrathecally. (Studies in HSP )

- Tizanidine – to treat nocturnal or intermittent spasms (studies available )

- Diazepam and clonazepam – to decrease intensity of spasms

- Oxybutynin chloride – an involuntary muscle relaxant and spasmolytic agent, used to reduce spasticity of the bladder in patients with bladder control problems

- Tolterodine tartate – an involuntary muscle relaxant and spasmolytic agent, used to reduce spasticity of the bladder in patients with bladder control problems

- Botulinum toxin – to reduce muscle overactivity (existing studies for HSP patients)

- Antidepressants (such as selective serotonin re-uptake inhibitors, tricyclic antidepressants and monoamine oxidase inhibitors) – for patients experiencing clinical depression

- Physical therapy – to restore and maintain the ability to move; to reduce muscle tone; to maintain or improve range of motion and mobility; to increase strength and coordination; to prevent complications, such as frozen joints, contractures, or bedsores.

Chorea can also be a manifestation of drug toxicity (for example, anticonvulsants, antiparkinson agents, neuroleptics, steroids, and estrogen), or a result of an infectious disease such as meningovascular syphilis, Lyme disease, viral encephalitis, and many others.

In general, a diet low in copper-containing foods is recommended with the avoidance of mushrooms, nuts, chocolate, dried fruit, liver, and shellfish.

Although HSP is a progressive condition, the prognosis for individuals with HSP varies greatly. It primarily affects the legs although there can be some upperbody involvement in some individuals. Some cases are seriously disabling while others are less disabling and are compatible with a productive and full life. The majority of individuals with HSP have a normal life expectancy.

When treating hemiballismus, it is first important to treat whatever may be causing the manifestation of this disorder. This could be hyperglycemia, infections, or neoplastic lesions. Some patients may not even need treatment because the disorder is not severe and can be self – limited.

Dopamine Blockers

When pharmacological treatment is necessary, the most standard type of drug to use is an antidopaminergic drug. Blocking dopamine is effective in about ninety percent of patients. Perphenazine, pimozide, haloperidol, and chlorpromazine are standard choices for treatment. Scientists are still unsure as to why this form of treatment works, as dopamine has not been directly linked to hemiballismus.

Anticonvulsants

An anticonvulsant called topiramate has helped patients in three cases and may be a viable treatment for the future.

ITB Therapy

Intrathecal baclofen (ITB) therapy is used to treat a variety of movement disorders such as cerebral palsy and multiple sclerosis. It can also be a possibility to help treat hemiballismus. In one case, before ITB the patient had an average of 10-12 ballism episodes of the right lower limb per hour. During episodes, the right hip would flex up to about 90 degrees, with a fully extended knee. After an ITB pump was implanted and the correct dosage was found, the frequency of ballistic right leg movements decreased to about three per day, and the right hip flexed to only 30 degrees. The patient was also able to better isolate individual distal joint movements in the right lower limb. The patient currently receives 202.4 microg/day of ITB and continues to benefit almost 6 years after the ITB pump was implanted.

Botulinum Injections

New uses for botulinum toxin have included treatment of hemiballismus. However, this is still in the early stages of testing. This treatment deals with the muscular manifestations of hemiballismus as opposed to the neurological causes.

Tetrabenazine

Tetrabenazine has been used to treat other movement disorders, but is now being used to treat hemiballismus. Patients using this medication have had a dramatic response. However, lowering the dosage leads to a return of symptoms. This drug works by depleting dopamine.

Antipsychotics

In one case, a patient had not been responding to haloperidol, thus the physician tried olanzapine. The patient made a significant recovery. More research is being performed on the use of these types of drugs in treating hemiballismus.

Functional Neurosurgery

Surgery as a treatment should only be used on patients with severe hemiballismus that has not responded to treatment. Lesioning of the globus pallidus or deep brain stimulation of the globus pallidus are procedures that can be used on humans. Usually, lesioning is favored over deep brain stimulation because of the maintenance required to continue stimulating the brain correctly and effectively.

There is currently no effective treatment or cure for PSP, although some of the symptoms can respond to nonspecific measures. The average age at symptoms onset is 63 and survival from onset averages 7 years with a wide variance. Pneumonia is a frequent cause of death.

Fifty percent of patients with acute Sydenham's chorea spontaneously recover after two to six months whilst mild or moderate chorea or other motor symptoms can persist for up to and over two years in some cases. Sydenham's is also associated with psychiatric symptoms with obsessive compulsive disorder being the most frequent manifestation.

Left untreated, Wilson's disease tends to become progressively worse and is eventually fatal. With early detection and treatment, most of those affected can live relatively normal lives. Liver and neurologic damage that occurs prior to treatment may improve, but it is often permanent.

Intracerebral hemorrhages is a severe condition requiring prompt medical attention. Treatment goals include lifesaving interventions, supportive measures, and control of symptoms. Treatment depends on the location, extent, and cause of the bleeding. Often, treatment can reverse the damage that has been done.

A craniotomy is sometimes done to remove blood, abnormal blood vessels, or a tumor. Medications may be used to reduce swelling, prevent seizures, lower blood pressure, and control pain.

Ballismus or ballism (called hemiballismus or hemiballism in its unilateral form) is a very rare movement disorder. It is a type of chorea caused in most cases by a decrease in activity of the subthalamic nucleus of the basal ganglia, resulting in the appearance of flailing, ballistic, undesired movements of the limbs. It can also appear rarely due to certain metabolic abnormalities. It is a rare movement disorder, being 500 times rarer than Parkinson's disease. Hemiballismus can cause significant disability. Symptoms can decrease during sleep.

Because the causes of CP are varied, a broad range of preventative interventions have been investigated.

Electronic fetal monitoring has not helped to prevent CP, and in 2014 the American College of Obstetricians and Gynecologists, the Royal Australian and New Zealand College of Obstetricians and Gynaecologists, and the Society of Obstetricians and Gynaecologists of Canada have acknowledged that there are no long-term benefits of electronic fetal monitoring. Prior to this, electronic fetal monitoring was widely used to prop up obstetric litigation.

In those at risk of an early delivery, magnesium sulphate appears to decrease the risk of cerebral palsy. It is unclear if it helps those who are born at term. In those at high risk of preterm labor a review found that moderate to severe CP was reduced by the administration of magnesium sulphate, and that adverse effects on the babies from the magnesium sulphate were not significant. Mothers who received magnesium sulphate could experience side effects such as respiratory depression and nausea. Caffeine is used to treat apnea of prematurity and reduces the risk of cerebral palsy in premature babies, but there are also concerns of long term negative effects. A moderate level of evidence has been shown for giving women antibiotics during preterm labour when their waters had not broken was associated with an increased risk of cerebral palsy in the child. Additionally, allowing a preterm birth to proceed rather than trying to delay the birth also had a moderate level of evidence for increased risk of cerebral palsy in the child.

Cooling high-risk full-term babies shortly after birth may reduce disability, but this may only be useful for some forms of the brain damage that causes CP.

There is no known cure for PSP and management is primarily supportive. PSP cases are often split into two subgroups, PSP-Richardson, the classic type, and PSP-Parkinsonism, where a short-term response to levodopa can be obtained. Dyskinesia is an occasional but rare complication of treatment. Amantadine is also sometimes helpful. After a few years the Parkinsonian variant tends to take on Richardson features. Other variants have been described. Botox can be used to treat neck dystonia and blephrospasm, but this can aggravate dysphagia.

Two studies have suggested that rivastigmine may help with cognitive aspects, but the authors of both studies have suggested a larger sampling be used. There is some evidence that the hypnotic zolpidem may improve motor function and eye movements, but only from small-scale studies.

Treatment of Sydenham's Chorea is based on the following principles:

1. The first tenet of treatment is to eliminate the streptococcus at a primary, secondary and tertiary level. Strategies involve the adequate treatment of throat and skin infections, with a course of penicillin when Sydenham's Chorea is newly diagnosed, followed by long-term penicillin prophylaxis. Behavioural and emotional changes may precede the movement disorders in a previously well child.

2. Treatment of movement disorders. Therapeutic efforts are limited to palliation of the movement disorders. Haloperidol is frequently used because of its anti-dopaminergic effect. It has serious potential side-effects, e.g., tardive dyskinesia. In a study conducted at the RFC, 25 out of 39 patients on haloperidol reported side-effects severe enough to cause the physician or parent to discontinue treatment or reduce the dose. Other medications which have been used to control the movements include pimozide, clonidine, valproic acid, carbamazepine and phenobarbitone.

3. Immunomodulatory interventions include steroids, intravenous immunoglobulins, and plasma exchange. Patients may benefit from treatment with steroids; controlled clinical trials are indicated to explore this further.

4. There are several historical case series reporting successful treatment of Sydenham's Chorea by inducing fever.

The treatment of Tourette's focuses on identifying and helping the individual manage the most troubling or impairing symptoms. Most cases of Tourette's are mild, and do not require pharmacological treatment; instead, psychobehavioral therapy, education, and reassurance may be sufficient. Treatments, where warranted, can be divided into those that target tics and comorbid conditions, which, when present, are often a larger source of impairment than the tics themselves. Not all people with tics have comorbid conditions, but when those conditions are present, they often take treatment priority.

There is no cure for Tourette's and no medication that works universally for all individuals without significant adverse effects. Knowledge, education and understanding are uppermost in management plans for tic disorders. The management of the symptoms of Tourette's may include pharmacological, behavioral and psychological therapies. While pharmacological intervention is reserved for more severe symptoms, other treatments (such as supportive psychotherapy or cognitive behavioral therapy) may help to avoid or ameliorate depression and social isolation, and to improve family support. Educating a patient, family, and surrounding community (such as friends, school, and church) is a key treatment strategy, and may be all that is required in mild cases.

Medication is available to help when symptoms interfere with functioning. The classes of medication with the most proven efficacy in treating tics—typical and atypical neuroleptics including risperidone (trade name Risperdal), ziprasidone (Geodon), haloperidol (Haldol), pimozide (Orap) and fluphenazine (Prolixin)—can have long-term and short-term adverse effects. The antihypertensive agents clonidine (trade name Catapres) and guanfacine (Tenex) are also used to treat tics; studies show variable efficacy, but a lower side effect profile than the neuroleptics. Stimulants and other medications may be useful in treating ADHD when it co-occurs with tic disorders. Drugs from several other classes of medications can be used when stimulant trials fail, including guanfacine (trade name Tenex), atomoxetine (Strattera) and tricyclic antidepressants. Clomipramine (Anafranil), a tricyclic, and SSRIs—a class of antidepressants including fluoxetine (Prozac), sertraline (Zoloft), and fluvoxamine (Luvox)—may be prescribed when a Tourette's patient also has symptoms of obsessive–compulsive disorder. Several other medications have been tried, but evidence to support their use is unconvincing.

Because children with tics often present to physicians when their tics are most severe, and because of the waxing and waning nature of tics, it is recommended that medication not be started immediately or changed often. Frequently, the tics subside with explanation, reassurance, understanding of the condition and a supportive environment. When medication is used, the goal is not to eliminate symptoms: it should be used at the lowest possible dose that manages symptoms without adverse effects, given that these may be more disturbing than the symptoms for which they were prescribed.

Cognitive behavioral therapy (CBT) is a useful treatment when OCD is present, and there is increasing evidence supporting the use of habit reversal (HRT) in the treatment of tics. There is evidence that HRT reduces tic severity, but there are methodological limitations in the studies, and a need for more trained specialists and better large-scale studies.

Relaxation techniques, such as exercise, yoga or meditation, may be useful in relieving the stress that may aggravate tics, but the majority of behavioral interventions (such as relaxation training and biofeedback, with the exception of habit reversal) have not been systematically evaluated and are not empirically supported therapies for Tourette's. Deep brain stimulation has been used to treat adults with severe Tourette's that does not respond to conventional treatment, but it is regarded as an invasive, experimental procedure that is unlikely to become widespread.

, studies on the impact of dietary interventions on the symptoms of Tourette's are scarce and methodologically poor, and a single dietary pattern has not been established. Anecdotal reports suggest that certain dietary interventions may relieve symptoms, such as gluten-free and low-sugar diets.