Paroxysmal Nonkinesigenic Dyskinesia (PNKD) is an episodic movement disorder first described by Mount and Reback in 1940 under the name "Familial paroxysmal choreoathetosis". It is a rare hereditary disease that affects various muscular

Muscular system

The muscular system is the anatomical system of a species that allows it to move. The muscular system in vertebrates is controlled through the nervous system, although some muscles can be completely autonomous.- Muscles :...

 and nervous system

Nervous system

The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...

s in the body, passing to roughly fifty percent of the offspring.

Alternate names

The condition can and has been referred to by a number of different names since it was first described, including the following:

• Paroxysmal nonkinesigenic dyskinesia
• PNKD
• Paroxysmal dystonic choreoathetosis
• PDC
• Mount-Reback syndrome (in honor of Lester Adrian Mount and S. Reback; the two doctors that classified it)
• Nonkinesigenic choreoathetosis
• Familial paroxysmal choreoathetosis
• Choreoathetosis familial paroxysmal
• FPD1
• DYT8
• Dystonia 8

Symptoms

The condition manifests itself as attacks lasting from a few minutes to several hours. Episodes only happen when the individual is awake, and they remain conscious throughout the attack. Symptoms are most severe in youth and lessen with age. Sufferers can have multiple attacks on a daily basis or may have periods of weeks or months between attacks. Symptoms experienced during attacks can vary and include dystonia

Dystonia

Dystonia is a neurological movement disorder, in which sustained muscle contractions cause twisting and repetitive movements or abnormal postures. The disorder may be hereditary or caused by other factors such as birth-related or other physical trauma, infection, poisoning or reaction to...

, chorea

Chorea (disease)

Choreia is an abnormal involuntary movement disorder, one of a group of neurological disorders called dyskinesias. The term choreia is derived from the Greek word χορεία , see choreia , as the quick movements of the feet or hands are vaguely comparable to dancing or piano playing.The term...

, athetosis

Athetosis

Athetosis is a symptom characterized by involuntary convoluted, writhing movements of the fingers, arms, legs, and neck. Movements typical of athetosis are sometimes called athetoid movements. Lesions to the brain are most often the direct cause of the symptoms, particularly to thecorpus striatum...

, ballismus, or a combination.

Triggers

While not the same in all people, there are several common triggers that can precipitate an attack:

• Moderate to high consumption of stimulants, such as alcohol
  Alcohol
  In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
  
  , caffeine
  Caffeine
  Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...
  
  , or nicotine
  Nicotine
  Nicotine is an alkaloid found in the nightshade family of plants that constitutes approximately 0.6–3.0% of the dry weight of tobacco, with biosynthesis taking place in the roots and accumulation occurring in the leaves...
  
  .
• Low amounts of energy due to hunger
  Hunger
  Hunger is the most commonly used term to describe the social condition of people who frequently experience the physical sensation of desiring food.-Malnutrition, famine, starvation:...
  
  , lack of sleep
  Sleep deprivation
  Sleep deprivation is the condition of not having enough sleep; it can be either chronic or acute. A chronic sleep-restricted state can cause fatigue, daytime sleepiness, clumsiness and weight loss or weight gain. It adversely affects the brain and cognitive function. Few studies have compared the...
  
  , illness
  Illness
  Illness is a state of poor health. Illness is sometimes considered another word for disease. Others maintain that fine distinctions exist...
  
  , or physical fatigue.
• Moderate to high presence of stress.
• Menstruation
  Menstruation
  Menstruation is the shedding of the uterine lining . It occurs on a regular basis in sexually reproductive-age females of certain mammal species. This article focuses on human menstruation.-Overview:...
  
   and ovulation
  Ovulation
  Ovulation is the process in a female's menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum . Ovulation also occurs in the estrous cycle of other female mammals, which differs in many fundamental ways from the menstrual cycle...
  
  .

Treatment

Most pharmacological treatments work poorly, but the best treatment is a low dosage of clonazepam

Clonazepam

Clonazepamis a benzodiazepine drug having anxiolytic, anticonvulsant, muscle relaxant, and hypnotic properties. It is marketed by Roche under the trade name Klonopin in the United States and Rivotril in Australia, Brazil, Canada and Europe...

, a muscle relaxant

Muscle relaxant

A muscle relaxant is a drug which affects skeletal muscle function and decreases the muscle tone. It may be used to alleviate symptoms such as muscle spasms, pain, and hyperreflexia. The term "muscle relaxant" is used to refer to two major therapeutic groups: neuromuscular blockers and spasmolytics...

. Patients may also benefit from other benzodiazepine

Benzodiazepine

A benzodiazepine is a psychoactive drug whose core chemical structure is the fusion of a benzene ring and a diazepine ring...

s, phenobarbital

Phenobarbital

Phenobarbital or phenobarbitone is a barbiturate, first marketed as Luminal by Friedr. Bayer et comp. It is the most widely used anticonvulsant worldwide, and the oldest still commonly used. It also has sedative and hypnotic properties but, as with other barbiturates, has been superseded by the...

, and other anticonvulsant

Anticonvulsant

The anticonvulsants are a diverse group of pharmaceuticals used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of bipolar disorder, since many seem to act as mood stabilizers, and in the treatment of neuropathic pain. The goal of an...

s such as valproic acid

Valproic acid

Valproic acid is a chemical compound that has found clinical use as an anticonvulsant and mood-stabilizing drug, primarily in the treatment of epilepsy, bipolar disorder, and, less commonly, major depression. It is also used to treat migraine headaches and schizophrenia...

. Affected individuals have reported garlic

Garlic

Allium sativum, commonly known as garlic, is a species in the onion genus, Allium. Its close relatives include the onion, shallot, leek, chive, and rakkyo. Dating back over 6,000 years, garlic is native to central Asia, and has long been a staple in the Mediterranean region, as well as a frequent...

to be effective for softening the attacks, but no studies have been done on this.