Torsion dystonia
Encyclopedia
Torsion dystonia is a disease characterized by painful muscle contraction
s resulting in uncontrollable distortions. This specific type of dystonia
is found in children, with symptoms starting around the ages of 11 or 12. It commonly begins with contractions in one general area such as an arm or a leg that continue to progress throughout the rest of the body. It takes roughly 5 years for the symptoms to completely progress to a debilitating state.
which results in a defect in a protein
called Torsin A
. A mutation in the DYT1 gene causes the loss of an amino acid
, glutamic acid, in the Torsin A protein. The defective protein creates a disruption in communication in neurons that control muscle movement and muscle control. This mutation is most usually inherited from a parent, but can occur sporadically. The disease is caused by a dominant allele
, meaning that the person affected needs only one copy of the mutated DYT1 gene to have symptoms. However, only 30 to 40 percent of those that do have the gene actually have symptoms, leading researchers to believe that there are other factors involved.
The first step for most with the disorder begins with some form of physical therapy in order for the patient to gain more control over the affected areas. The therapy can help patients with their posture and gain control over the areas of their body that they have the most problems with.
The second step in the treatment process is medication. The medications focus on the chemicals released by neurotransmitters in the nervous system, which control muscle movement. The medications on the market today are Anticholinergics, Benzodiazepines, Baclofen, Dopaminergic agents/Dopamine-depleting agents, and Tetrabenezine. Each medication is started on a low dosage and gradually increased to higher doses as the disease progresses and the side effects are known for the individual.
A more site-specific treatment is the injection of botulinum toxin
. It is injected directly into the muscle and works much the same way the oral medications do—by blocking neurotransmitters. The injections are not a treatment for the disease, but are a means to control its symptoms.
A fourth option in the treatment for the symptoms of Torsion Dystonia is surgery. Surgery is performed only if the patient does not respond to the oral medications or the injections. The type of surgery performed is specific to the type of Dystonia that the patient has.
. The occurrence of torsion dystonia in the Ashkenazi Jewish population as stated by the Department of Epidemiology and Public Health of Yale University School of Medicine in New Haven, CT; "Reports dating to the beginning of this century describe Ashkenazi Jewish (AJ) families with multiple cases of ITD either in siblings (Schwalbe 1908; Bernstein 1912; Abrahamson 1920) or in parents and offspring (Wechsler and Brock 1922; Mankowsky and Czerny 1929; Regensberg 1930). The first comprehensive evaluation of the mode of inheritance of ITD in Jewish and non-Jewish families was described by Zeman and Dyken (1967), who concluded that the disorder was inherited as an autosomal dominant with incomplete penetrance in both populations. Although they concluded that the gene frequency was higher in the AJ population than in non-Jews, no difference in mode of inheritance or disease mechanism was construed."
Dr. Gregory Cochran
, when researching information linking genetic disorders and their possible link with Ashkenazi intelligence
, said that "he became interested in the subject upon learning that patients with a particular Ashkenazic disease known as torsion dystonia were told by their physicians that 'the positive thing is that this makes you smart' ".
Interestingly, patients with torsion dystonia are reported to have an average IQ of about 122, which is more than a standard deviation above average (average IQ = 100, standard deviation = 15).
Dystonia is related to Parkinson's disease
, as Torsin A has scientifically been shown to have a neurotherapeutic effect on dopamine
receptors
.
Muscle contraction
Muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. While under tension, the muscle may lengthen, shorten, or remain the same...
s resulting in uncontrollable distortions. This specific type of 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...
is found in children, with symptoms starting around the ages of 11 or 12. It commonly begins with contractions in one general area such as an arm or a leg that continue to progress throughout the rest of the body. It takes roughly 5 years for the symptoms to completely progress to a debilitating state.
Causes
The disease is caused by a genetic disorderGenetic disorder
A genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions....
which results in a defect in a protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
called Torsin A
Torsin A
Torsin-1A is a protein that in humans is encoded by the TOR1A gene.-External links:*-Further reading:...
. A mutation in the DYT1 gene causes the loss of an amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
, glutamic acid, in the Torsin A protein. The defective protein creates a disruption in communication in neurons that control muscle movement and muscle control. This mutation is most usually inherited from a parent, but can occur sporadically. The disease is caused by a dominant allele
Allele
An allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...
, meaning that the person affected needs only one copy of the mutated DYT1 gene to have symptoms. However, only 30 to 40 percent of those that do have the gene actually have symptoms, leading researchers to believe that there are other factors involved.
Classification
There are several types of torsion dystonia that affect different areas of the body. However, it is unknown if the gene that causes Early Onset Torsion Dystonia is responsible for the other dystonias as well.- Cervical dystonia (spasmodic torticollis): A type of dystonia that affects the head, neck and spine. It can create problems by the characteristic turning of the head and neck from side to side.
- BlepharospasmBlepharospasmA blepharospasm , is any abnormal contraction or twitch of the eyelid....
: This type of dystonia causes involuntary contraction of the eyelids. The main concern for this dystonia is that it can cause the eyelids to close involuntarily and for indefinite periods of time.
- Oromandibular dystoniaOromandibular dystoniaOromandibular dystonia is a form of focal dystonia affecting the mouth, jaw, and tongue.Botulinum toxin has been used in treatment....
: A dystonia of the jaw, lips, and/or the tongue. It can make eating and swallowing very complicated due to the jaw being held open or shut for periods of time.
- Spasmodic dysphoniaSpasmodic dysphoniaSpasmodic dysphonia is a voice disorder characterized by involuntary movements of one or more muscles of the larynx during speech.- Types of spasmodic dysphonia :...
: A dystonia of the vocal cords. The complications surrounding this form of dystonia are speech related and can cause symptoms such as speech that wavers, speech that sounds like a whisper, or speech that is hesitant.
- Writer's crampWriter's crampWriter's cramp, also called mogigraphia and scrivener's palsy, causes a cramp or spasm affecting certain muscles of the hand and/or fingers. Writer's cramp is a task-specific focal dystonia of the hand...
(occupational dystonia): A dystonia that affects the muscles of the hand and forearm. It is triggered by attempting to write or execute other fine-motor hand functions.
- Orofacial-Buccal dystonia (Meige's or Brueghal's Syndrome): A combination of blepharospasm and oromandibular dystonia.
- Early-onset torsion dystonia: The most severe type of dystonia, it begins in an arm or leg and progresses to the rest of the body until the man or women (although in most cases a child) is confined to a wheel chair.
Treatment
There is no cure for torsion dystonia. However, there are several medical approaches that can be taken in order to lessen the symptoms of the disease. The treatment must be patient specific, taking into consideration all of the previous and current health complications. The doctor that creates the treatment must have intimate knowledge of the patients’ health and create a treatment plan that covers all of the symptoms focusing on the most chronic areas.The first step for most with the disorder begins with some form of physical therapy in order for the patient to gain more control over the affected areas. The therapy can help patients with their posture and gain control over the areas of their body that they have the most problems with.
The second step in the treatment process is medication. The medications focus on the chemicals released by neurotransmitters in the nervous system, which control muscle movement. The medications on the market today are Anticholinergics, Benzodiazepines, Baclofen, Dopaminergic agents/Dopamine-depleting agents, and Tetrabenezine. Each medication is started on a low dosage and gradually increased to higher doses as the disease progresses and the side effects are known for the individual.
A more site-specific treatment is the injection of botulinum toxin
Botulinum toxin
Botulinum toxin is a protein produced by the bacterium Clostridium botulinum, and is considered the most powerful neurotoxin ever discovered. Botulinum toxin causes Botulism poisoning, a serious and life-threatening illness in humans and animals...
. It is injected directly into the muscle and works much the same way the oral medications do—by blocking neurotransmitters. The injections are not a treatment for the disease, but are a means to control its symptoms.
A fourth option in the treatment for the symptoms of Torsion Dystonia is surgery. Surgery is performed only if the patient does not respond to the oral medications or the injections. The type of surgery performed is specific to the type of Dystonia that the patient has.
Prevalence
The disease is more commonly found amongst Ashkenazi JewsAshkenazi Jews
Ashkenazi Jews, also known as Ashkenazic Jews or Ashkenazim , are the Jews descended from the medieval Jewish communities along the Rhine in Germany from Alsace in the south to the Rhineland in the north. Ashkenaz is the medieval Hebrew name for this region and thus for Germany...
. The occurrence of torsion dystonia in the Ashkenazi Jewish population as stated by the Department of Epidemiology and Public Health of Yale University School of Medicine in New Haven, CT; "Reports dating to the beginning of this century describe Ashkenazi Jewish (AJ) families with multiple cases of ITD either in siblings (Schwalbe 1908; Bernstein 1912; Abrahamson 1920) or in parents and offspring (Wechsler and Brock 1922; Mankowsky and Czerny 1929; Regensberg 1930). The first comprehensive evaluation of the mode of inheritance of ITD in Jewish and non-Jewish families was described by Zeman and Dyken (1967), who concluded that the disorder was inherited as an autosomal dominant with incomplete penetrance in both populations. Although they concluded that the gene frequency was higher in the AJ population than in non-Jews, no difference in mode of inheritance or disease mechanism was construed."
Dr. Gregory Cochran
Gregory Cochran
Gregory M. Cochran is a physicist and adjunct professor of anthropology at the University of Utah who has developed some new ideas in evolutionary medicine and genetic anthropology. Cochran is known for several controversial theories....
, when researching information linking genetic disorders and their possible link with Ashkenazi intelligence
Ashkenazi intelligence
Whether Ashkenazi Jews have higher intelligence than other ethnic groups has been an occasional subject of scientific controversy. The 2005 paper "Natural History of Ashkenazi Intelligence" by Cochran, Hardy, and Harpending, argued on the basis of inherited diseases and the peculiar economic...
, said that "he became interested in the subject upon learning that patients with a particular Ashkenazic disease known as torsion dystonia were told by their physicians that 'the positive thing is that this makes you smart' ".
Interestingly, patients with torsion dystonia are reported to have an average IQ of about 122, which is more than a standard deviation above average (average IQ = 100, standard deviation = 15).
Dystonia is related to Parkinson's disease
Parkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...
, as Torsin A has scientifically been shown to have a neurotherapeutic effect on dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...
receptors
Receptor (biochemistry)
In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...
.
External links
- http://www.dystonia-foundation.org
- http://www.dystonia-parkinsons.org
- http://www.medicinenet.com/dystonia/article.htm
- http://www.dystonia-foundation.org/pages/complementary_therapy/156.php
- http://www.biochem.arizona.edu/classes/bioc461/Biochem499/AngelaPulsifer/dystonia1.htm
- http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1683634