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Friedreich's Ataxia
Friedreich's ataxia (FRDA) is a rare, inherited, autosomal recessive neurodegenerative disorder that primarily affects the nervous system, causing progressive damage to the spinal cord, peripheral nerves, and cerebellum, leading to impaired muscle coordination (''ataxia''). The condition typically manifests in childhood or adolescence, with initial symptoms including difficulty walking, loss of balance, and poor coordination. As the disease progresses, it can also impact speech, vision, and hearing. Many individuals with Friedreich's ataxia develop scoliosis, diabetes, and hypertrophic cardiomyopathy, a serious heart condition that is a leading cause of mortality in patients. Friedreich's ataxia is caused by mutations in the ''FXN'' gene, which result in reduced production of frataxin, a protein essential for mitochondrial function, particularly in iron-sulfur cluster biogenesis. The deficiency of frataxin disrupts cellular energy production and leads to oxidative stress, co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frataxin
Frataxin is a protein that in humans is encoded by the ''FXN'' gene. It is located in the mitochondrion and Frataxin mRNA is mostly expressed in tissues with a high metabolic rate. The function of frataxin is not clear but it is involved in assembly of iron-sulfur clusters. It has been proposed to act as either an iron chaperone or an iron storage protein. Reduced expression of frataxin is the cause of Friedreich's ataxia. Structure X-ray crystallography has shown that human frataxin consists of a β-sheet that supports a pair of parallel α-helices, forming a compact αβ sandwich. Frataxin homologues in other species are similar, sharing the same core structure. However, the frataxin tail sequences, extending from the end of one helix, diverge in sequence and differ in length. Human frataxin has a longer tail sequence than frataxin found in bacteria or yeast. It is hypothesized that the purpose of the tail is to stabilize the protein. Like most mitochondrial protei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tachycardia
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal (such as with exercise) or abnormal (such as with electrical problems within the heart). Complications Tachycardia can lead to fainting. When the rate of blood flow becomes too rapid, or fast blood flow passes on damaged endothelium, it increases the friction within vessels resulting in turbulence and other disturbances. According to the Virchow's triad, this is one of the three conditions (along with hypercoagulability and endothelial injury/dysfunction) that can lead to thrombosis (i.e., blood clots within vessels). Causes Some causes of tachycardia include: * Adrenergic storm * Anaemia * Anxiety * Atrial fibrillation * Atrial flutter * Atrial tachycardia * Atrioventricular reentrant tachycardia * AV nodal reentrant tachy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proprioception
Proprioception ( ) is the sense of self-movement, force, and body position. Proprioception is mediated by proprioceptors, a type of sensory receptor, located within muscles, tendons, and joints. Most animals possess multiple subtypes of proprioceptors, which detect distinct kinesthetic parameters, such as joint position, movement, and load. Although all mobile animals possess proprioceptors, the structure of the sensory organs can vary across species. Proprioceptive signals are transmitted to the central nervous system, where they are integrated with information from other Sensory nervous system, sensory systems, such as Visual perception, the visual system and the vestibular system, to create an overall representation of body position, movement, and acceleration. In many animals, sensory feedback from proprioceptors is essential for stabilizing body posture and coordinating body movement. System overview In vertebrates, limb movement and velocity (muscle length and the rate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pallesthesia
Pallesthesia (\ˌpal-es-ˈthē-zh(ē-)ə\), or vibratory sensation, is the ability to perceive vibration.Campbell, W. W., & DeJong, R. N. (2013). DeJong's the neurologic examination. lectronic resourceWilliam W. Campbell. Philadelphia, PA : Lippincott Williams & Wilkins, c2013. This sensation, often conducted through skin and bone, is usually generated by mechanoreceptors such as Pacinian corpuscles, Merkel disk receptors, and tactile corpuscles. All of these receptors stimulate an action potential in afferent nerves (sensory neurons) found in various layers of the skin and body. The afferent neuron travels to the spinal column and then to the brain where the information is processed. Damage to the peripheral nervous system or central nervous system can result in a decline or loss of pallesthesia. A diminished sense of vibration is known as ''pallhypesthesia''. To determine whether a patient has diminished or absent pallesthesia, testing can be conducted using a tuning fork at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stomping Gait
Stomping gait (or sensory ataxia gait) is a form of gait abnormality. It indicates involvement of posterior column. Posterior column carries proprioception which is essential for coordination of motor movements. __TOC__ Presentation ''Uncoordinated walking '' Conditions associated with a stomping gait * Friedreich's ataxia * Pernicious anemia * Tabes dorsalis * Peripheral neuropathy * Spinal cord disease * Multiple sclerosis Multiple sclerosis (MS) is an autoimmune disease resulting in damage to myelinthe insulating covers of nerve cellsin the brain and spinal cord. As a demyelinating disease, MS disrupts the nervous system's ability to Action potential, transmit ... References {{med-sign-stub Gait abnormalities ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Truncal Ataxia
Truncal ataxia (or trunk ataxia) is a wide-based "drunken sailor" gait characterized by uncertain starts and stops, lateral deviations and unequal steps. It is an instability of the trunk and often seen during sitting. It is most visible when shifting position or walking heel-to-toe. As a result of this gait impairment, falling is a concern in patients with ataxia. Truncal ataxia affects the muscles closer to the body such as the trunk, shoulder girdle and hip girdle. It is involved in gait stability. Truncal ataxia is different from appendicular ataxia. Appendicular ataxia affects the movements of the arms and legs. It is caused by lesions of the cerebellar hemispheres. Causes Truncal ataxia is caused by midline damage to the cerebellar vermis. There are at least 34 conditions that cause truncal ataxia. Common * Alcohol intoxication * Cerebellar infarction * Cerebellar hemorrhage * Cerebellar ataxia * Multiple sclerosis * Friedreich's ataxia * Drugs such as Benzodiazepin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dysmetria
Dysmetria () is a lack of coordination of movement typified by the undershoot or overshoot of intended position with the hand, arm, leg, or eye. It is a type of ataxia. It can also include an inability to judge distance or scale. Hypermetria and hypometria are, respectively, overshooting and undershooting the intended position. Presentation Associated diseases Dysmetria is often found in individuals with multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), and persons who have had tumors or strokes. Persons who have been diagnosed with autosomal dominant spinocerebellar ataxia (SCAs) also exhibit dysmetria. There are many types of SCAs and though many exhibit similar symptoms (one being dysmetria), they are considered to be heterogeneous. Friedreich's ataxia is a relatively common cause of dysmetria. Cerebellar malformations extending to the brainstem can also present with dysmetria. Causes The actual cause of dysmetria is thought to be caused by lesions in the cerebe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saccadic
In vision science, a saccade ( ; ; ) is a quick, simultaneous movement of both eyes between two or more phases of focal points in the same direction. In contrast, in smooth-pursuit movements, the eyes move smoothly instead of in jumps. Controlled cortically by the frontal eye fields (FEF), or subcortically by the superior colliculus, saccades serve as a mechanism for focal points, rapid eye movement, and the fast phase of optokinetic nystagmus. The word appears to have been coined in the 1880s by French ophthalmologist Émile Javal, who used a mirror on one side of a page to observe eye movement in silent reading, and found that it involves a succession of discontinuous individual movements. Function Humans and many organisms do not look at a scene in steadiness; instead, the eyes move around, locating interesting parts of the scene and building up a three-dimensional 'map' corresponding to the scene (as opposed to the graphical map of avians, which often relies upon detect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nystagmus
Nystagmus is a condition of involuntary (or voluntary, in some cases) Eye movement (sensory), eye movement. People can be born with it but more commonly acquire it in infancy or later in life. In many cases it may result in visual impairment, reduced or limited vision. In normal eyesight, while the Human head, head rotates about an Axis of rotation, axis, distant visual images are sustained by rotating eyes in the opposite direction of the respective axis. The semicircular canals in the vestibule of the ear sense angular acceleration, and send signals to the nuclei for eye movement in the brain. From here, a signal is relayed to the extraocular muscles to allow one's gaze to fix on an object as the head moves. Nystagmus occurs when the semicircular canals are stimulated (e.g., by means of the caloric test, or by disease) while the head is stationary. The direction of ocular movement is related to the semicircular canal that is being stimulated. There are two key forms of nystagm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebellar
The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or even larger. In humans, the cerebellum plays an important role in motor control and cognitive functions such as attention and language as well as emotional control such as regulating fear and pleasure responses, but its movement-related functions are the most solidly established. The human cerebellum does not initiate movement, but contributes to coordination, precision, and accurate timing: it receives input from sensory systems of the spinal cord and from other parts of the brain, and integrates these inputs to fine-tune motor activity. Cerebellar damage produces disorders in fine movement, equilibrium, posture, and motor learning in humans. Anatomically, the human cerebellum has the appearance of a separate structure attached to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tachyarrhythmias
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal (such as with exercise) or abnormal (such as with electrical problems within the heart). Complications Tachycardia can lead to fainting. When the rate of blood flow becomes too rapid, or fast blood flow passes on damaged endothelium, it increases the friction within vessels resulting in turbulence and other disturbances. According to the Virchow's triad, this is one of the three conditions (along with hypercoagulability and endothelial injury/dysfunction) that can lead to thrombosis (i.e., blood clots within vessels). Causes Some causes of tachycardia include: * Adrenergic storm * Anaemia * Anxiety * Atrial fibrillation * Atrial flutter * Atrial tachycardia * Atrioventricular reentrant tachycardia * AV nodal reentrant tachycardi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
