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Hyperlysinemia
Hyperlysinemia is an autosomal recessive metabolic disorder characterized by an abnormal increase of lysine in the blood, but appears to be benign. It is caused by mutations in '' AASS'', which encodes α-aminoadipic semialdehyde synthase. Hyperlysinemia is associated with ectopia lentis (a displacement or malposition of the eye's crystalline lens) in humans. Signs and symptoms While hyperlysinemia typically causes no health problems, patients may exhibit behavioral abnormalities, delayed speech and language development, infantile hypotonia, intellectual disability, microcephaly, neurodevelopmental delay, psychomotor retardation, seizures, short attention spans, and short stature. Genetics Hyperlysinemia is inherited in an autosomal recessive manner. This means the defective gene responsible for the disorder is located on an autosome An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AASS (gene)
Alpha-aminoadipic semialdehyde synthase is an enzyme encoded by the AASS gene in humans and is involved in their major lysine degradation pathway. It is similar to the separate enzymes coded for by the LYS1 and LYS9 genes in yeast, and related to, although not similar in structure, the bifunctional enzyme found in plants. In humans, mutations in the AASS gene, and the corresponding alpha-aminoadipic semialdehyde synthase enzyme are associated with familial hyperlysinemia. This rare disease is inherited in an autosomal recessive pattern and patients often have no clinical symptoms. Function The alpha-aminoadipic semialdehyde synthase protein catalyzes the first two steps in the mammalian L-lysine degradation via saccharopine pathway within the mitochondria, which is thought to be the main metabolic route for lysine degradation in upper eukaryotes. The specific subpathway that this enzyme focuses on is the synthesis of glutaryl-CoA from L-lysine. Glutaryl-CoA can act as an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saccharopinuria
Saccharopinuria (an excess of saccharopine in the urine), also called saccharopinemia, saccharopine dehydrogenase deficiency or alpha-aminoadipic semialdehyde synthase deficiency, is a variant form of hyperlysinemia. It is caused by a partial deficiency of the enzyme saccharopine dehydrogenase, which plays a secondary role in the lysine metabolic pathway. Inheritance is thought to be autosomal recessive, but this cannot be established as individuals affected by saccharopinuria typically have only a 40% reduction in functional enzyme. See also * Hyperlysinemia Hyperlysinemia is an autosomal recessive metabolic disorder characterized by an abnormal increase of lysine in the blood, but appears to be benign. It is caused by mutations in '' AASS'', which encodes α-aminoadipic semialdehyde synthase. Hype ... References External links * Amino acid metabolism disorders Rare diseases {{genetic-disorder-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha-aminoadipic Semialdehyde Synthase
Alpha-aminoadipic semialdehyde synthase is an enzyme encoded by the AASS gene in humans and is involved in their major lysine degradation pathway. It is similar to the separate enzymes coded for by the LYS1 and LYS9 genes in yeast, and related to, although not similar in structure, the bifunctional enzyme found in plants. In humans, mutations in the AASS gene, and the corresponding alpha-aminoadipic semialdehyde synthase enzyme are associated with familial hyperlysinemia. This rare disease is inherited in an autosomal recessive pattern and patients often have no clinical symptoms. Function The alpha-aminoadipic semialdehyde synthase protein catalyzes the first two steps in the mammalian L-lysine degradation via saccharopine pathway within the mitochondria, which is thought to be the main metabolic route for lysine degradation in upper eukaryotes. The specific subpathway that this enzyme focuses on is the synthesis of glutaryl-CoA from L-lysine. Glutaryl-CoA can act as an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lysine
Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. Lysine contains an α-amino group (which is in the protonated form when the lysine is dissolved in water at physiological pH), an α-carboxylic acid group (which is in the deprotonated form when the lysine is dissolved in water at physiological pH), and a side chain (which is partially protonated when the lysine is dissolved in water at physiological pH), and so it is classified as a basic, charged (in water at physiological pH), aliphatic amino acid. It is encoded by the codons AAA and AAG. Like almost all other amino acids, the α-carbon is chiral and lysine may refer to either enantiomer or a racemic mixture of both. For the purpose of this article, lysine will refer to the biologically active enantiomer L-lysine, where the α-carbon is in the ''S'' configuration. The human body cannot synthesize lysine. It is essential in humans and must therefore be obtained from the diet. In orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectopia Lentis
Ectopia lentis is a displacement or malposition of the eye's lens from its normal location. A partial dislocation of a lens is termed lens subluxation or subluxated lens; a complete dislocation of a lens is termed lens luxation or luxated lens. Ectopia lentis in dogs and cats Although observed in humans and cats, ectopia lentis is most commonly seen in dogs. Ciliary zonules normally hold the lens in place. Abnormal development of these zonules can lead to primary ectopia lentis, usually a bilateral condition. Luxation can also be a secondary condition, caused by trauma, cataract formation (decrease in lens diameter may stretch and break the zonules), or glaucoma (enlargement of the globe stretches the zonules). Steroid administration weakens the zonules and can lead to luxation, as well. Lens luxation in cats can occur secondary to anterior uveitis (inflammation of the inside of the eye). Anterior lens luxation With anterior lens luxation, the lens pushes into the iris or ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psychomotor Retardation
Psychomotor retardation involves a slowing down of thought and a reduction of physical movements in an individual. It can cause a visible slowing of physical and emotional reactions, including speech and affect. Psychomotor retardation is most commonly seen in people with major depression and in the depressed phase of bipolar disorder; it is also associated with the adverse effects of certain drugs, such as benzodiazepines. Particularly in an inpatient setting, psychomotor retardation may require increased nursing care to ensure adequate food and fluid intake and sufficient personal care. Informed consent for treatment is more difficult to achieve in the presence of this condition. Causes * Psychiatric disorders: anxiety disorders, bipolar disorder, eating disorders, schizophrenia, severe depression, etc. * Psychiatric medicines (if taken as prescribed or improperly, overdosed, or mixed with alcohol) * Parkinson's disease * Genetic disorders: Qazi–Markouizos syndrome, S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amino Acid Metabolism Disorders
In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of electrons. Amines can also exist as hetero cyclic compounds. Aniline is the simplest aromatic amine, consisting of a benzene ring bonded to an amino group. Amines are classified into three types: primary (1°), secondary (2°), and tertiary (3°) amines. Primary amines (1°) contain one alkyl or aryl substituent and have the general formula RNH2. Secondary amines (2°) have two alkyl or aryl groups attached to the nitrogen atom, with the general formula R2NH. Tertiary amines (3°) contain three substituent groups bonded to the nitrogen atom, and are represented by the formula R3N. The functional group present in primary amines is called the amino group. Classification of amines Amines can be classified according to the nature and number o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Carrier
A hereditary carrier (genetic carrier or just carrier), is a person or other organism that has inherited a recessive allele for a genetic trait or mutation but usually does not display that trait or show symptoms of the disease. Carriers are, however, able to pass the allele onto their offspring, who may then express the genetic trait. Carriers in autosomal inheritances Autosomal dominant-recessive inheritance is made possible by the fact that the individuals of most species (including all higher animals and plants) have two alleles of most hereditary predispositions because the chromosomes in the cell nucleus are usually present in pairs (diploid). Carriers can be female or male as the autosomes are homologous independently from the sex. In carriers the expression of a certain characteristic is recessive. The individual has both a genetic predisposition for the dominant trait and a genetic predisposition for the recessive trait, and the dominant expression prevails in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autosomal Recessive - En
An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosomal (sex chromosome) pairs, which may have different structures. The DNA in autosomes is collectively known as atDNA or auDNA. For example, humans have a diploid genome that usually contains 22 pairs of autosomes and one allosome pair (46 chromosomes total). The autosome pairs are labeled with numbers (1–22 in humans) roughly in order of their sizes in base pairs, while allosomes are labelled with their letters. By contrast, the allosome pair consists of two X chromosomes in females or one X and one Y chromosome in males. Unusual combinations XYY, XXY, XXX, XXXX, XXXXX or XXYY, among other irregular combinations, are known to occur and usually cause developmental abnormalities. Autosomes still contain sexual determination genes even though they are not sex chromosomes. For example, the SRY gene on the Y chromosom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short Stature
Short stature refers to a height of a human which is below typical. Whether a person is considered short depends on the context. Because of the lack of preciseness, there is often disagreement about the degree of shortness that should be called ''short''. Dwarfism is the condition of being very short, often caused by a medical condition. In a medical context, short stature is typically defined as an adult height that is more than two standard deviations below a population’s mean for age and sex, which corresponds to the shortest 2.3% of individuals in that population. Shortness in children and young adults nearly always results from below-average growth in childhood, while shortness in older adults usually results from loss of height due to kyphosis of the spine or collapsed vertebrae from osteoporosis. The most common causes of short stature in childhood are constitutional growth delay or familial short stature. From a medical perspective, severe shortness can be a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Attention Span
Attention span is the amount of time spent concentrating on a task before becoming distracted. Distractibility occurs when attention is uncontrollably diverted to another activity or sensation. ''Attention training'' is said to be part of education, particularly in the way students are trained to remain focused on a topic of discussion for extended periods, developing listening and analytical skills in the process. By age Measuring humans’ estimated attention span depends on what the attention is being used for. The terms “transient attention” and “selective sustained attention” are used to separate short term and focused attention. Transient attention is a short-term response to a stimulus that temporarily attracts or distracts attention. Researchers disagree on the exact amount of the human transient attention span, whereas selective sustained attention, also known as focused attention, is the level of attention that produces consistent results on a task over time. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
