Dystonia - What is 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 (e.g., lead poisoning) or reaction to pharmaceutical drugs, particularly neuroleptics.

Types of dystonia

Generalized
Focal
Segmental
Intermediate
Acute Dystonic Reaction

Generalized dystonias

Normal birth history and milestones
Autosomal dominant
childhood onset
starts in lower limbs and spreads upwards
also known as "idiopathic torsion dystonia" (old terminology "dystonia musculrum deformans")

Focal dystonias

These are the most common dystonias and tend to be classified as follows:

Name	Location	Description
Cervical dystonia (spasmodic torticollis)	muscles of the neck	Causes the head to rotate to one side, to pull down towards the chest, or back, or a combination of these postures.
Blepharospasm	muscles around the eyes	The sufferer experiences rapid blinking of the eyes or even their forced closure causing effective blindness.
Oculogyric crisis	muscles of eye and head	An extreme and sustained (usually) upward deviation of the eyes often with convergence causing diplopia. It is frequently associated with backwards and lateral flexion of the neck and either widely opened mouth or jaw clenching. Frequently a result of antiemetics such as the neuroleptics (e.g., prochlorperazine) or metoclopramide.
Oromandibular dystonia	muscles of the jaw and muscles of tongue	Causes distortions of the mouth and tongue.
Spasmodic dysphonia/Laryngeal dystonia	muscles of larynx	Causes the voice to sound broken or reducing it to a whisper.
Focal hand dystonia (also known as musician's or writer's cramp).	single muscle or small group of muscles in the hand	It interferes with activities such as writing or playing a musical instrument by causing involuntary muscular contractions. The condition is sometimes "task-specific," meaning that it is generally only apparent during certain activities. Focal hand dystonia is neurological in origin, and is not due to normal fatigue. The loss of precise muscle control and continuous unintentional movement results in painful cramping and abnormal positioning that makes continued use of the affected body parts impossible.

The combination of blepharospasmodic contractions and oromandibular dystonia is called cranial dystonia or Meige's syndrome.

Segmental dystonias

Segmental dystonias affect two adjoining parts of the body:

Hemidystonia affects an arm and a leg on one side of the body.
Multifocal dystonia affects many different parts of the body.
Generalized dystonia affects most of the body, frequently involving the legs and back.

Genetic / primary

Name	OMIM	Gene	Locus	Alt Name
DYT1 (or EOTD)		DYT1	9q34	early-onset torsion dystonia
DYT2		unknown	unknown	autosomal recessive torsion dystonia
DYT3		TAF1	Xq13	X-linked torsion dystonia
DYT4		unknown	unknown	autosomal dominant torsion dystonia
DYT5 (or DRD)		GCH1	14q22.1-q22.2	Dopamine-responsive dystonia
DYT6		THAP1	8p11.21
DYT7		unknown	18p	Primary cervical dystonia
DYT8 (or PNKD1)		MR1	2q35	paroxysmal nonkinesigenic dyskinesia 1
DYT9		possibly KCNA3	1p	episodic choreoathetosis/spasticity
DYT10 (or EKD1)		unknown	16p11.2-q12.1	episodic kinesigenic dyskinesia 1
DYT11		SGCE	7q21	Myoclonic dystonia
DYT12		ATP1A3	19q12-q13.2
DYT13		unknown, near D1S2667	1p36.32-p36.13
DYT14	See DYT5
DYT15		unknown	18p11	Myoclonic dystonia
DYT16		PRKRA	2q31.3
DYT17		unknown, near D20S107	20p11.2-q13.12
DYT18		SLC2A1	1p35-p31.3
DYT19 (or EKD2)		unknown	16q13-q22.1	episodic kinesigenic dyskinesia 2
DYT20 (or PNKD2)		unknown	2q31	paroxysmal nonkinesigenic dyskinesia 2

There is a group called myoclonus dystonia or myoclonic dystonia, where some cases are hereditary and have been associated with a missense mutation in the dopamine-D2 receptor. Some of these cases have responded remarkably to alcohol.