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Donohue Syndrome
Donohue syndrome (also known as leprechaunism) is an extremely rare and severe genetic disorder. ''Leprechaunism'' derives its name from the hallmark elvish features (small stature, bulging eyes, thick lips, and upturned nostrils) exhibited by the affected individuals. The disease is caused by a mutation in the INSR gene, which contains the genetic information for the formation of insulin receptors. As a result, affected individuals have either a decreased number of insulin receptors, or insulin receptor with greatly impaired functionality. The lack and impairment of insulin receptor functionality leads to an inability to regulate blood glucose levels through severe insulin resistance. This will ultimately lead to affected development of tissues and organs throughout the body. In addition to the physical abnormalities, leprechaunism is also characterized by endocrine system abnormalities that can lead to conditions such as hyperglycemia (high blood glucose levels), hypoglycemia (low ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insulin Receptor
The insulin receptor (IR) is a transmembrane receptor that is activated by insulin, IGF-I, IGF-II and belongs to the large class of receptor tyrosine kinase. Metabolically, the insulin receptor plays a key role in the regulation of glucose homeostasis, a functional process that under degenerate conditions may result in a range of clinical manifestations including diabetes and cancer. Insulin signalling controls access to blood glucose in body cells. When insulin falls, especially in those with high insulin sensitivity, body cells begin only to have access to lipids that do not require transport across the membrane. So, in this way, insulin is the key regulator of fat metabolism as well. Biochemically, the insulin receptor is encoded by a single gene , from which alternate splicing during transcription results in either IR-A or IR-B isoforms. Downstream post-translational events of either isoform result in the formation of a proteolytically cleaved α and β subunit, which upo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Introns
An intron is any nucleotide sequence within a gene that is not expressed or operative in the final RNA product. The word ''intron'' is derived from the term ''intragenic region'', i.e. a region inside a gene."The notion of the cistron .e., gene... must be replaced by that of a transcription unit containing regions which will be lost from the mature messenger – which I suggest we call introns (for intragenic regions) – alternating with regions which will be expressed – exons." (Gilbert 1978) The term ''intron'' refers to both the DNA sequence within a gene and the corresponding RNA sequence in RNA transcripts. The non-intron sequences that become joined by this RNA processing to form the mature RNA are called exons. Introns are found in the genes of most organisms and many viruses and they can be located in both protein-coding genes and genes that function as RNA (noncoding genes). There are four main types of introns: tRNA introns, group I introns, group II introns, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insulin-like Growth Factor
The insulin-like growth factors (IGFs) are proteins with high sequence similarity to insulin. IGFs are part of a complex system that cells use to communicate with their physiologic environment. This complex system (often referred to as the IGF "axis") consists of two cell-surface receptors (IGF1R and IGF2R), two ligands (IGF-1 and IGF-2), a family of seven high-affinity IGF-binding proteins ( IGFBP1 to IGFBP7), as well as associated IGFBP degrading enzymes, referred to collectively as proteases. IGF1/GH axis The IGF "axis" is also commonly referred to as the Growth Hormone/IGF-1 Axis. Insulin-like growth factor 1 (commonly referred to as IGF-1 or at times using Roman numerals as IGF-I) is mainly secreted by the liver as a result of stimulation by growth hormone (GH). IGF-1 is important for both the regulation of normal physiology, as well as a number of pathological states, including cancer. The IGF axis has been shown to play roles in the promotion of cell proliferation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gluconeogenesis
Gluconeogenesis (GNG) is a metabolic pathway that results in the generation of glucose from certain non- carbohydrate carbon substrates. It is a ubiquitous process, present in plants, animals, fungi, bacteria, and other microorganisms. In vertebrates, gluconeogenesis occurs mainly in the liver and, to a lesser extent, in the cortex of the kidneys. It is one of two primary mechanisms – the other being degradation of glycogen ( glycogenolysis) – used by humans and many other animals to maintain blood sugar levels, avoiding low levels ( hypoglycemia). In ruminants, because dietary carbohydrates tend to be metabolized by rumen organisms, gluconeogenesis occurs regardless of fasting, low-carbohydrate diets, exercise, etc. In many other animals, the process occurs during periods of fasting, starvation, low-carbohydrate diets, or intense exercise. In humans, substrates for gluconeogenesis may come from any non-carbohydrate sources that can be converted to pyruvate or in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GLUT4
Glucose transporter type 4 (GLUT4), also known as solute carrier family 2, facilitated glucose transporter member 4, is a protein encoded, in humans, by the ''SLC2A4'' gene. GLUT4 is the insulin-regulated glucose transporter found primarily in adipose tissues and striated muscle (skeletal and cardiac). The first evidence for this distinct glucose transport protein was provided by David James in 1988. The gene that encodes GLUT4 was cloned and mapped in 1989. At the cell surface, GLUT4 permits the facilitated diffusion of circulating glucose down its concentration gradient into muscle and fat cells. Once within cells, glucose is rapidly phosphorylated by glucokinase in the liver and hexokinase in other tissues to form glucose-6-phosphate, which then enters glycolysis or is polymerized into glycogen. Glucose-6-phosphate cannot diffuse back out of cells, which also serves to maintain the concentration gradient for glucose to passively enter cells. Structure Like all protein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pancreas
The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an endocrine and a digestive exocrine function. 99% of the pancreas is exocrine and 1% is endocrine. As an endocrine gland, it functions mostly to regulate blood sugar levels, secreting the hormones insulin, glucagon, somatostatin, and pancreatic polypeptide. As a part of the digestive system, it functions as an exocrine gland secreting pancreatic juice into the duodenum through the pancreatic duct. This juice contains bicarbonate, which neutralizes acid entering the duodenum from the stomach; and digestive enzymes, which break down carbohydrates, proteins, and fats in food entering the duodenum from the stomach. Inflammation of the pancreas is known as pancreatitis, with common causes including chronic alcohol use and gallstones. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Cell
Beta cells (β-cells) are a type of cell found in pancreatic islets that synthesize and secrete insulin and amylin. Beta cells make up 50–70% of the cells in human islets. In patients with Type 1 diabetes, beta-cell mass and function are diminished, leading to insufficient insulin secretion and hyperglycemia. Function The primary function of a beta cell is to produce and release insulin and amylin. Both are hormones which reduce blood glucose levels by different mechanisms. Beta cells can respond quickly to spikes in blood glucose concentrations by secreting some of their stored insulin and amylin while simultaneously producing more. Primary cilia on beta cells regulate their function and energy metabolism. Cilia deletion can lead to islet dysfunction and type 2 diabetes. Insulin synthesis Beta cells are the only site of insulin synthesis in mammals. As glucose stimulates insulin secretion, it simultaneously increases proinsulin biosynthesis, mainly through translation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allele
An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chromosomal or genomic location of a gene or any other genetic element is called a locus (plural: loci) and alternative DNA sequences at a locus are called alleles." The simplest alleles are single nucleotide polymorphisms (SNP). but they can also be insertions and deletions of up to several thousand base pairs. Popular definitions of 'allele' typically refer only to different alleles within genes. For example, the ABO blood grouping is controlled by the ABO gene, which has six common alleles (variants). In population genetics, nearly every living human's phenotype for the ABO gene is some combination of just these six alleles. Most alleles observed result in little or no change in the function of the gene product it codes for. Howeve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compound Heterozygote
In medical genetics, compound heterozygosity is the condition of having two or more heterogeneous recessive alleles at a particular locus that can cause genetic disease in a heterozygous state; that is, an organism is a compound heterozygote when it has two recessive alleles for the same gene, but with those two alleles being different from each other (for example, both alleles might be mutated but at different locations). Compound heterozygosity reflects the diversity of the mutation base for many autosomal recessive genetic disorders; mutations in most disease-causing genes have arisen many times. This means that many cases of disease arise in individuals who have two unrelated alleles, who technically are heterozygotes, but both the alleles are defective. These disorders are often best known in some classic form, such as the homozygous recessive case of a particular mutation that is widespread in some population. In its compound heterozygous forms, the disease may have lower pene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consanguineous
Consanguinity ("blood relation", from Latin '' consanguinitas'') is the characteristic of having a kinship with another person (being descended from a common ancestor). Many jurisdictions have laws prohibiting people who are related by blood from marrying or having sexual relations with each other. The degree of consanguinity that gives rise to this prohibition varies from place to place. Such rules are also used to determine heirs of an estate according to statutes that govern intestate succession, which also vary from jurisdiction to jurisdiction. In some places and time periods, cousin marriage is allowed or even encouraged; in others, it is taboo, and considered to be incest. The degree of relative consanguinity can be illustrated with a ''consanguinity table'' in which each level of lineal consanguinity (''generation'' or ''meiosis'') appears as a row, and individuals with a collaterally consanguineous relationship share the same row. The Knot System is a numerical notatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diabetes
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased appetite. If left untreated, diabetes can cause many health complications. Acute complications can include diabetic ketoacidosis, hyperosmolar hyperglycemic state, or death. Serious long-term complications include cardiovascular disease, stroke, chronic kidney disease, foot ulcers, damage to the nerves, damage to the eyes, and cognitive impairment. Diabetes is due to either the pancreas not producing enough insulin, or the cells of the body not responding properly to the insulin produced. Insulin is a hormone which is responsible for helping glucose from food get into cells to be used for energy. There are three main types of diabetes mellitus: * Type 1 diabetes results from failure of the pancreas to produce enough insulin due ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methionine
Methionine (symbol Met or M) () is an essential amino acid in humans. As the precursor of other amino acids such as cysteine and taurine, versatile compounds such as SAM-e, and the important antioxidant glutathione, methionine plays a critical role in the metabolism and health of many species, including humans. It is encoded by the codon AUG. Methionine is also an important part of angiogenesis, the growth of new blood vessels. Supplementation may benefit those suffering from copper poisoning. Overconsumption of methionine, the methyl group donor in DNA methylation, is related to cancer growth in a number of studies. Methionine was first isolated in 1921 by John Howard Mueller. Biochemical details Methionine (abbreviated as Met or M; encoded by the codon AUG) is an α-amino acid that is used in the biosynthesis of proteins. It contains a carboxyl group (which is in the deprotonated −COO− form under biological pH conditions), an amino group (which is in the protonat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
