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GTPCH1
GTP cyclohydrolase I (GTPCH) () is a member of the GTP cyclohydrolase family of enzymes. GTPCH is part of the folate and biopterin biosynthesis pathways. It is responsible for the hydrolysis of guanosine triphosphate (GTP) to form 7,8-dihydroneopterin triphosphate (7,8-DHNP-3'-TP, 7,8-NH2-3'-TP). Gene GTPCH is encoded by the gene ''GCH1''. Several alternatively spliced transcript variants encoding different isoforms have been described; however, not all of the variants give rise to a functional enzyme. Clinical significance At least 94 disease-causing mutations in this gene have been discovered. Mutations in this gene are associated with two disorders: autosomal recessive GTP cyclohydrolase I deficiency and autosomal dominant GTP cyclohydrolase I deficiency. These may present with malignant phenylketonuria (PKU) and hyperphenylalaninemia (HPA) and lead to a lack of certain neurotransmitters ( ... (HPA) and lead to a lack of certain neurotransmitters ( dopamine">... (HPA) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autosomal Dominant GTP Cyclohydrolase I Deficiency
Autosomal dominant GTP cyclohydrolase I deficiency (AD-GTPCHD) is a disease caused by dysfunction of GTP cyclohydrolase I, an enzyme that plays an important role in the synthesis of tetrahydrobiopterin, and, as a consequence, of dopamine. This condition is one of the six known causes of tetrahydrobiopterin deficiency and is the most frequently-reported cause of dopa-responsive dystonia. Symptoms In more than half the cases, the clinical picture is dominated by postural or action-induced dystonia of one or both lower limbs manifesting as gait difficulties. Dystonia gradually worsens during the day and becomes less pronounced after a period of rest. The fluctuating pattern is highly typical of this disease, especially in the first 30 years, after which this diurnal variation becomes less prominent. The typical age at onset is during the first decade of life, although an onset in the second decade of life is also common, and in rare cases the disease may present itself in the first 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autosomal Recessive GTP Cyclohydrolase I Deficiency
Autosomal recessive GTP cyclohydrolase I deficiency (AR-GTPCHD) is a disorder associated with the deficient operation of the enzyme GTP cyclohydrolase I. The condition leads to insufficient production of the cofactor tetrahydrobiopterin necessary for the proper synthesis of dopamine and serotonin and for maintenance of adequate levels of phenylalanine. As of 2020, autosomal recessive GTP cyclohydrolase I deficiency was one of the six known causes of tetrahydrobiopterin deficiency. It is also considered part of the spectrum of dopa-responsive dystonias. Symptoms Patients may present with developmental delay, axial hypotonia, delayed development of speech, or dysarthria. The list of possible motor disturbances includes dystonia, oculogyric crises, parkinsonism/hypokinesia. Patients may have a number of psychiatric symptoms. Biochemically, patients present with hyperphenylalaninemia, and usually have decreased levels of ..., and usually have decreased levels of biopterin and neopter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malignant
Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not self-limited in its growth, is capable of invading into adjacent tissues, and may be capable of spreading to distant tissues. A benign tumor has none of those properties. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis. Malignant tumors are also characterized by genome instability, so that cancers, as assessed by whole genome sequencing, frequently have between 10,000 and 100,000 mutations in their entire genomes. Cancers usually show tumour heterogeneity, containing multiple subclones. They also frequently have reduced expression of DNA repair enzymes due to epigenetic methylation of DNA repair genes or altered microRNAs that control DNA repair gene expression. Tumours can be detected through the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autonomic Dysfunction
Dysautonomia or autonomic dysfunction is a condition in which the autonomic nervous system (ANS) does not work properly. This may affect the functioning of the heart, bladder, intestines, sweat glands, pupils, and blood vessels. Dysautonomia has many causes, not all of which may be classified as neuropathic. A number of conditions can feature dysautonomia, such as Parkinson's disease, multiple system atrophy, dementia with Lewy bodies, Ehlers-Danlos syndromes, autoimmune autonomic ganglionopathy and autonomic neuropathy, HIV/AIDS, autonomic failure, and postural orthostatic tachycardia syndrome. The diagnosis is achieved through functional testing of the ANS, focusing on the affected organ system. Investigations may be performed to identify underlying disease processes that may have led to the development of symptoms or autonomic neuropathy. Symptomatic treatment is available for many symptoms associated with dysautonomia, and some disease processes can be directly treate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tremor
A tremor is an involuntary, somewhat rhythmic, muscle contraction and relaxation involving oscillations or twitching movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, face, head, vocal folds, trunk, and legs. Most tremors occur in the hands. In some people, a tremor is a symptom of another neurological disorder. A very common tremor is the teeth chattering, usually induced by cold temperatures or by fear. Types Tremor is most commonly classified by clinical features and cause or origin. Some of the better-known forms of tremor, with their symptoms, include the following: * Cerebellar tremor (also known as intention tremor) is a slow, broad tremor of the extremities that occurs at the end of a purposeful movement, such as trying to press a button or touching a finger to the tip of one's nose. Cerebellar tremor is caused by lesions in or damage to the cerebellum resulting from stroke, tumor, or disease s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypertonia
Hypertonia is a term sometimes used synonymously with spasticity and rigidity in the literature surrounding damage to the central nervous system, namely upper motor neuron lesions. Impaired ability of damaged motor neurons to regulate descending pathways gives rise to disordered spinal reflexes, increased excitability of muscle spindles, and decreased synaptic inhibition. These consequences result in abnormally increased muscle tone of symptomatic muscles. Some authors suggest that the current definition for spasticity, the velocity-dependent over-activity of the stretch reflex, is not sufficient as it fails to take into account patients exhibiting increased muscle tone in the absence of stretch reflex over-activity. They instead suggest that "reversible hypertonia" is more appropriate and represents a treatable condition that is responsive to various therapy modalities like drug and/or physical therapy. Presentation Symptoms associated with central nervous systems disorders a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypotonia
Hypotonia is a state of low muscle tone (the amount of tension or resistance to stretch in a muscle), often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases and disorders that affect motor nerve control by the brain or muscle strength. Hypotonia is a lack of resistance to passive movement, whereas muscle weakness results in impaired active movement. Central hypotonia originates from the central nervous system, while peripheral hypotonia is related to problems within the spinal cord, peripheral nerves and/or skeletal muscles. Severe hypotonia in infancy is commonly known as floppy baby syndrome. Recognizing hypotonia, even in early infancy, is usually relatively straightforward, but diagnosing the underlying cause can be difficult and often unsuccessful. The long-term effects of hypotonia on a child's development and later life depend primarily on the severity of the muscle weakness and the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Developmental Delays
Specific developmental disorders (SDD) was a classification of disorders characterized by delayed development in one specific area or areas.Ahuja Vyas: ''Textbook of Postgraduate Psychiatry'' (2 Vols.), 2nd ed. 1999 Specific developmental disorders were contrasted to pervasive developmental disorders which were characterized by delays in the development of multiple basic functions including socialization and communication. ICD-10 taxonomy The tenth revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) has four categories of developmental disorders: specific developmental disorders of speech and language, specific developmental disorders of scholastic skills, specific developmental disorder of motor function, and mixed specific developmental disorder. DSM-III taxonomy In the third edition of the '' Diagnostic and Statistical Manual of Mental Disorders'' (DSM-III),Dennis Cantwell & Lorian Baker: ''Developmental Speech and Language ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dystonia
Dystonia is a neurological hyperkinetic movement disorder in which sustained or repetitive muscle contractions result in twisting and repetitive movements or abnormal fixed postures. The movements may resemble a tremor. Dystonia is often intensified or exacerbated by physical activity, and symptoms may progress into adjacent muscles. 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, or stress. Treatment must be highly customized to the needs of the individual and may include oral medications, chemodenervation botulinum neurotoxin injections, physical therapy, or other supportive therapies, and surgical procedures such as deep brain stimulation. Classification There are multiple types of dystonia, and many diseases and conditions may cause dystonia. Dystonia is classified by: # Clinical characteristics such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serotonin
Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and vasoconstriction. Approximately 90% of the serotonin that the body produces is in the intestinal tract. Biochemically, the indoleamine molecule derives from the amino acid tryptophan, via the (rate-limiting) Tryptophan hydroxylase, hydroxylation of the 5 position on the ring (forming the intermediate 5-Hydroxytryptophan, 5-hydroxytryptophan), and then Aromatic L-amino acid decarboxylase, decarboxylation to produce serotonin. Serotonin is primarily found in the enteric nervous system located in the human gastrointestinal tract, gastrointestinal tract (GI tract). However, it is also produced in the central nervous system (CNS), specifically in the raphe nuclei located in the brainstem, Merkel cells located in the skin, Neuroendocrine cell#Pulmo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epinephrine
Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands and by a small number of neurons in the medulla oblongata. It plays an essential role in the fight-or-flight response by increasing blood flow to muscles, heart output by acting on the SA node, pupil dilation response, and blood sugar level. It does this by binding to alpha and beta receptors. It is found in many animals, including humans, and some single-celled organisms. It has also been isolated from the plant ''Scoparia dulcis'' found in Northern Vietnam. Medical uses As a medication, it is used to treat several conditions, including allergic reaction anaphylaxis, cardiac arrest, and superficial bleeding. Inhaled adrenaline may be used to improve the symptoms of croup. It may also be used for asthma when other treatments are not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
