Hyperekplexia

Hyperekplexia

Infobox_Disease
Name = PAGENAME


Caption =
DiseasesDB = 7208
ICD10 =
ICD9 = ICD9|759.89
ICDO =
OMIM = 149400
MedlinePlus =
eMedicineSubj =
eMedicineTopic =
MeshName =
MeshNumber =

Hyperexplexia, also called "Hyperekplexia," is a neurological disorder characterized by an exaggerated startle response in situations of distress.

History

The disorder was first described in 1958 by Kirstein and Silfverskiold, who reported a family with 'drop seizures'. In 1962 Drs. Kok and Bruyn reported an unidentified hereditary syndrome, initially started as hypertonia in infants. [Kok, O.; Bruyn, G. W. An unidentified hereditary disease. (Letter) Lancet I: 1359, 1962.] The disease is responsible for Sudden Infant Death Syndrome in some cases. [http://pmj.bmj.com/cgi/content/full/77/911/570] It was confirmed as hereditary in 1990 by neurologist Dr. Angelika Hahn when a child was diagnosed within 48 hours of its birth of having hyperexplexia.

Clinical signs

The most prevalent clinical sign of hyperekplexia is an exaggerated startle response consisting of forced closure of the eyes and an extension of the extremities followed by a period of generalised stiffness similar to paralysis and possibly resulting in uncontrolled falling. It can be mistaken for cataplexy in narcolepsy sufferers.

Minor forms of hyperekplexia display an exaggerated startle response without the generalised stiffness.

The symptoms usually subside within the first year of life although it is not unknown for some symptoms to proceed into adulthood.

Cause

The cause of hyperekplexia is genetic. A mutation in the fifth chromosome (5q33.2-5q33.3) in the alpha-1 subunit of the glycine receptor is the most predominant cause of this neurological malfunction.

Mutations have also been discovered in the beta subunit gene (GLRB) (4q31) such as the point mutation G229D and within the glycine transporter 2 gene (GlyT2) (11p15)

An unverified link has been speculated between hyperekplexia and Asperger's Syndrome.

Treatment

As of now, there is no cure for hyperekplexia. A genetic counselor may prescribe clonazepam or valproic acid to lessen the symptoms with reasonable success.

ee also

* Jumping Frenchmen of Maine
* Latah
* Stiff person syndrome

References


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Look at other dictionaries:

  • hyperekplexia — hyperekplexia. См. гиперэкплексия. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • hyperekplexia — noun A neurological disorder characterized by an exaggerated startle response in situations of distress. Syn: hyperexplexia …   Wiktionary

  • Hyperekplexia — A genetic disorder also known as hyperexplexia in which babies have an exaggerated startle reflex (reaction). This disorder was not recognized until 1962 when it was described by Drs. Kok and Bruyn as a disease with the onset at birth of… …   Medical dictionary

  • startle disease — hyperekplexia …   Medical dictionary

  • гиперэкплексия — hyperekplexia, startle disease гиперэкплексия. НЗЧ нейрологического типа, характеризующееся ригидностью мышц, мышечными спазмами в ответ на внезапные раздражители (“startle”), грыжей и др.; наследуется по аутосомно доминантному типу, фактор Г.… …   Молекулярная биология и генетика. Толковый словарь.

  • GLRA1 — Glycine receptor, alpha 1 (startle disease/hyperekplexia, stiff man syndrome), also known as GLRA1, is a human gene. PBB Summary section title = summary text = The inhibitory glycine receptor mediates postsynaptic inhibition in the spinal cord… …   Wikipedia

  • Clonazepam — Not to be confused with camazepam, chlorpromazine, cinolazepam, or clobazam. Clonazepam …   Wikipedia

  • Stiff person syndrome — (SPS) (or stiff man syndrome; also known as Stiffperson s Syndrome or Moersch Woltman Condition) is a rare neurologic disorder of unknown etiology characterized by progressive rigidity and stiffness, primarily of the axial musculature, that is… …   Wikipedia

  • Disease — Illness or sickness often characterized by typical patient problems (symptoms) and physical findings (signs). Disruption sequence: The events that occur when a fetus that is developing normally is subjected to a destructive agent such as the… …   Medical dictionary

  • Hyperexplexia — A genetic disorder in which babies have an exaggerated startle reflex (reaction). This disorder was not recognized until 1962 when it was described by Drs. Kok and Bruyn as a disease with the onset at birth of hypertonia (stiffness), exaggerated… …   Medical dictionary

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