In genetics, a promoter is a region of DNA that initiates transcription of a particular gene. Promoters are located near the transcription start sites of genes, on the same strand and upstream on the DNA. Promoters can be about 100–1000 base pairs long. For transcription to take place, the enzyme that synthesizes RNA, known as RNA polymerase, must attach to the DNA near a gene. Promoters contain specific DNA sequences such as response elements that provide a secure initial binding site for RNA polymerase and for proteins called transcription factors that recruit RNA polymerase; these transcription factors have specific activator or repressor sequences of corresponding nucleotides that attach to specific promoters and regulate gene expression. In bacteria The promoter is recognized by RNA polymerase and an associated sigma factor, which in turn are brought to the promoter DNA by an activator protein's binding to its own DNA binding site nearby. In eukaryotes The process is more complicated, at least seven different factors are necessary for the binding of an RNA polymerase II to the promoter.
Promoters represent critical elements that can work in concert with other regulatory regions to direct the level of transcription of a given gene. A promoter is induced in response to changes in abundance or conformation of regulatory proteins in a cell, which enable activating transcription factors to recruit RNA polymerase; as promoters are immediately adjacent to the gene in question, positions in the promoter are designated relative to the transcriptional start site, where transcription of DNA begins for a particular gene. In the cell nucleus, it seems that promoters are distributed preferentially at the edge of the chromosomal territories for the co-expression of genes on different chromosomes. Furthermore, in humans, promoters show certain structural features characteristic for each chromosome. Core promoter – the minimal portion of the promoter required to properly initiate transcriptionIncludes the transcription start site and elements directly upstream A binding site for RNA polymerase RNA polymerase I: transcribes genes encoding 18S, 5.8S and 28S ribosomal RNAs RNA polymerase II: transcribes genes encoding messenger RNA and certain small nuclear RNAs and microRNA RNA polymerase III: transcribes genes encoding transfer RNA, 5s ribosomal RNAs and other small RNAs General transcription factor binding sites, e.g. TATA box, B recognition element.
Many other elements/motifs may be present. There is no such thing as a set of "universal elements" found in every core promoter. Proximal promoter – the proximal sequence upstream of the gene that tends to contain primary regulatory elements Approximately 250 base pairs upstream of the start site Specific transcription factor binding sites Distal promoter – the distal sequence upstream of the gene that may contain additional regulatory elements with a weaker influence than the proximal promoter Anything further upstream Specific transcription factor binding sites In bacteria, the promoter contains two short sequence elements 10 and 35 nucleotides upstream from the transcription start site; the sequence at -10 has the consensus sequence TATAAT. The sequence at -35 has the consensus sequence TTGACA; the above consensus sequences, while conserved on average, are not found intact in most promoters. On average, only 3 to 4 of the 6 base pairs in each consensus sequence are found in any given promoter.
Few natural promoters have been identified to date that possess intact consensus sequences at both the -10 and -35. The optimal spacing between the -35 and -10 sequences is 17 bp; some promoters contain one or more upstream promoter element subsites. The above promoter sequences are recognized only by RNA polymerase holoenzyme containing sigma-70. RNA polymerase holoenzymes containing other sigma factors recognize different core promoter sequences. <-- upstream downstream --> 5'-XXXXXXXPPPPPPXXXXXXPPPPPPXXXXGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGXXXX-3' -35 -10 Gene to be transcribed for -10 sequence T A T A A T 77% 76% 60% 61% 56% 82% for -35 sequence T T G A C A 69% 79% 61% 56% 54% 54% Eukaryotic promoters are diverse and can be difficult to characterize, recent studies show that they are divided in more than 10 classes. Gene promoters are located upstream of the gene and can have regulatory elements several kilobases away from the transcriptional start site. In eukaryotes, the transcriptional complex can cause the DNA to bend back on itself, which allows for placement of regulatory sequences far from the actual site of transcription.
Eukaryotic RNA-polymerase-II-dependent promoters can contain a TATA element, recognized by the general transcription factor TATA-binding protein. The TATA element and BRE are located close to the transcriptional start site (
Amino acids are organic compounds containing amine and carboxyl functional groups, along with a side chain specific to each amino acid. The key elements of an amino acid are carbon, hydrogen and nitrogen, although other elements are found in the side chains of certain amino acids. About 500 occurring amino acids are known and can be classified in many ways, they can be classified according to the core structural functional groups' locations as alpha-, beta-, gamma- or delta- amino acids. In the form of proteins, amino acid residues form the second-largest component of human muscles and other tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis. In biochemistry, amino acids having both the amine and the carboxylic acid groups attached to the first carbon atom have particular importance, they are known as α-amino acids. They include the 22 proteinogenic amino acids, which combine into peptide chains to form the building-blocks of a vast array of proteins.
These are all L-stereoisomers, although a few D-amino acids occur in bacterial envelopes, as a neuromodulator, in some antibiotics. Twenty of the proteinogenic amino acids are encoded directly by triplet codons in the genetic code and are known as "standard" amino acids; the other two are selenocysteine, pyrrolysine. Pyrrolysine and selenocysteine are encoded via variant codons. N-formylmethionine is considered as a form of methionine rather than as a separate proteinogenic amino acid. Codon–tRNA combinations not found in nature can be used to "expand" the genetic code and form novel proteins known as alloproteins incorporating non-proteinogenic amino acids. Many important proteinogenic and non-proteinogenic amino acids have biological functions. For example, in the human brain and gamma-amino-butyric acid are the main excitatory and inhibitory neurotransmitters. Hydroxyproline, a major component of the connective tissue collagen, is synthesised from proline. Glycine is a biosynthetic precursor to porphyrins used in red blood cells.
Carnitine is used in lipid transport. Nine proteinogenic amino acids are called "essential" for humans because they cannot be produced from other compounds by the human body and so must be taken in as food. Others may be conditionally essential for medical conditions. Essential amino acids may differ between species; because of their biological significance, amino acids are important in nutrition and are used in nutritional supplements, fertilizers and food technology. Industrial uses include the production of drugs, biodegradable plastics, chiral catalysts; the first few amino acids were discovered in the early 19th century. In 1806, French chemists Louis-Nicolas Vauquelin and Pierre Jean Robiquet isolated a compound in asparagus, subsequently named asparagine, the first amino acid to be discovered. Cystine was discovered in 1810, although its monomer, remained undiscovered until 1884. Glycine and leucine were discovered in 1820; the last of the 20 common amino acids to be discovered was threonine in 1935 by William Cumming Rose, who determined the essential amino acids and established the minimum daily requirements of all amino acids for optimal growth.
The unity of the chemical category was recognized by Wurtz in 1865, but he gave no particular name to it. Usage of the term "amino acid" in the English language is from 1898, while the German term, Aminosäure, was used earlier. Proteins were found to yield amino acids after enzymatic acid hydrolysis. In 1902, Emil Fischer and Franz Hofmeister independently proposed that proteins are formed from many amino acids, whereby bonds are formed between the amino group of one amino acid with the carboxyl group of another, resulting in a linear structure that Fischer termed "peptide". In the structure shown at the top of the page, R represents a side chain specific to each amino acid; the carbon atom next to the carboxyl group is called the α–carbon. Amino acids containing an amino group bonded directly to the alpha carbon are referred to as alpha amino acids; these include amino acids such as proline which contain secondary amines, which used to be referred to as "imino acids". The alpha amino acids are the most common form found in nature, but only when occurring in the L-isomer.
The alpha carbon is a chiral carbon atom, with the exception of glycine which has two indistinguishable hydrogen atoms on the alpha carbon. Therefore, all alpha amino acids but glycine can exist in either of two enantiomers, called L or D amino acids, which are mirror images of each other. While L-amino acids represent all of the amino acids found in proteins during translation in the ribosome, D-amin
G protein-coupled receptor
G protein-coupled receptors known as seven--transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, G protein–linked receptors, constitute a large protein family of receptors that detect molecules outside the cell and activate internal signal transduction pathways and cellular responses. Coupling with G proteins, they are called seven-transmembrane receptors because they pass through the cell membrane seven times. G protein-coupled receptors are found only in eukaryotes, including yeast, choanoflagellates, animals; the ligands that bind and activate these receptors include light-sensitive compounds, pheromones and neurotransmitters, vary in size from small molecules to peptides to large proteins. G protein-coupled receptors are involved in many diseases, are the target of 34% of all modern medicinal drugs. There are two principal signal transduction pathways involving the G protein-coupled receptors: the cAMP signal pathway and the phosphatidylinositol signal pathway.
When a ligand binds to the GPCR it causes a conformational change in the GPCR, which allows it to act as a guanine nucleotide exchange factor. The GPCR can activate an associated G protein by exchanging the GDP bound to the G protein for a GTP; the G protein's α subunit, together with the bound GTP, can dissociate from the β and γ subunits to further affect intracellular signaling proteins or target functional proteins directly depending on the α subunit type. GPCRs are an important drug target and 34% of all Food and Drug Administration approved drugs target 108 members of this family; the global sales volume for these drugs is estimated to be 180 billion US dollars as of 2018. The 2012 Nobel Prize in Chemistry was awarded to Brian Kobilka and Robert Lefkowitz for their work, "crucial for understanding how G protein-coupled receptors function". There have been at least seven other Nobel Prizes awarded for some aspect of G protein–mediated signaling; as of 2012, two of the top ten global best-selling drugs act by targeting G protein-coupled receptors.
The exact size of the GPCR superfamily is unknown, but at least 810 different human genes have been predicted to code for them from genome sequence analysis. Although numerous classification schemes have been proposed, the superfamily was classically divided into three main classes with no detectable shared sequence homology between classes; the largest class by far is class A. Of class A GPCRs, over half of these are predicted to encode olfactory receptors, while the remaining receptors are liganded by known endogenous compounds or are classified as orphan receptors. Despite the lack of sequence homology between classes, all GPCRs have a common structure and mechanism of signal transduction; the large rhodopsin A group has been further subdivided into 19 subgroups. According to the classical A-F system, GPCRs can be grouped into 6 classes based on sequence homology and functional similarity: Class A Class B Class C Class D Class E Class F More an alternative classification system called GRAFS has been proposed for vertebrate GPCRs.
They correspond to classical classes C, A, B2, F, B. An early study based on available DNA sequence suggested that the human genome encodes 750 G protein-coupled receptors, about 350 of which detect hormones, growth factors, other endogenous ligands. 150 of the GPCRs found in the human genome have unknown functions. Some web-servers and bioinformatics prediction methods have been used for predicting the classification of GPCRs according to their amino acid sequence alone, by means of the pseudo amino acid composition approach. GPCRs are involved in a wide variety of physiological processes; some examples of their physiological roles include: The visual sense: The opsins evolved from early GPCRs over 650 million years ago, use a photoisomerization reaction to translate electromagnetic radiation into cellular signals. Rhodopsin, for example, uses the conversion of 11-cis-retinal to all-trans-retinal for this purpose; the gustatory sense: GPCRs in taste cells mediate release of gustducin in response to bitter-, umami- and sweet-tasting substances.
The sense of smell: Receptors of the olfactory epithelium bind odorants and pheromones Behavioral and mood regulation: Receptors in the mammalian brain bind several different neurotransmitters, including serotonin, dopamine, GABA, glutamate Regulation of immune system activity and inflammation: Chemokine receptors bind ligands that mediate intercellular communication between cells of the immune system. GPCRs are involved in immune-modulation and directly involved in suppression of TLR-induced immune responses from T cells. Autonomic nervous system transmission: Both the sympathetic and parasympathetic nervous systems are regulated by GPCR pathways, responsible for control of many automatic functions of the body such as blood pressure, heart rate, digestive processes Cell density sensing: A novel GPCR role in regulating cell density sensing. Homeostasis modulation. Involved in growth and metastasis of some types of tumors. Used in the endocrine syste
G beta-gamma complex
The G beta-gamma complex is a bound dimeric protein complex, composed of one Gβ and one Gγ subunit, is a component of heterotrimeric G proteins. Heterotrimeric G proteins called guanosine nucleotide-binding proteins, consist of three subunits, called alpha and gamma subunits, or Gα, Gβ, Gγ; when a G protein-coupled receptor is activated, Gα dissociates from Gβγ, allowing both subunits to perform their respective downstream signaling effects. One of the major functions of Gβγ is the inhibition of the Gα subunit; the individual subunits of the G protein complex were first identified in 1980 when the regulatory component of adenylate cyclase was purified, yielding three polypeptides of different molecular weights. It was thought that Gα, the largest subunit, was the major effector regulatory subunit, that Gβγ was responsible for inactivating the Gα subunit and enhancing membrane binding. However, downstream signalling effects of Gβγ were discovered when the purified Gβγ complex was found to activate a cardiac muscarinic K+ channel.
Shortly after, the Gβγ complex associated with a mating factor receptor-coupled G protein in yeast was found to initiate a pheromone response. Although these hypotheses were controversial, Gβγ has since been shown to directly regulate as many different protein targets as the Gα subunit. Possible roles of the Gβγ complex in retinal rod photoreceptors have been investigated, with some evidence for the maintenance of Gα inactivation. However, these conclusions were drawn from in vitro experiments under unphysiological conditions, the physiological role of the Gβγ complex in vision is still unclear. Recent in vivo findings demonstrate the necessity of the transducin Gβγ complex in the functioning of rod photoreceptors under low light conditions; the Gβγ subunit is a dimer composed of two polypeptides, however it acts functionally as a monomer, as the individual subunits do not separate, have not been found to function independently. The Gβ subunit is a member of the β-propellor family of proteins, which possess 4-8 antiparallel β-sheets arranged in the shape of a propeller.
Gβ contains a 7 bladed β-propeller, each blade arranged around a central axis and composed of 4 antiparallel β-sheets. The amino acid sequence contains 7 WD repeat motifs of about 40 amino acids, each conserved and possessing the Trp-Asp dipeptide that gives the repeat its name; the Gγ subunit is smaller than Gβ, is unstable on its own, requiring interaction with Gβ to fold, explaining the close association of the dimer. In the Gβγ dimer, the Gγ subunit wraps around the outside of Gβ, interacting through hydrophobic associations, exhibits no tertiary interactions with itself; the N terminus helical domains of the two subunits form a coiled coil with one another that extends away from the core of the dimer. To date, 5 β-subunit and 11 γ-subunit genes and have been identified in mammals; the Gβ genes have similar sequences, while greater variation is seen in the Gγ genes, indicating that the functional specificity of the Gβγ dimer may be dependent on the type of Gγ subunit involved. Of additional structural interest is the discovery of a so-called “hotspot” present on the surface of the Gβγ dimer.
Synthesis of the subunits occurs in the cytosol. Folding of the β-subunit is thought to be aided by the chaperone CCT, which prevents aggregation of folded subunits. A second chaperone, PhLP, binds to the CCT/Gβ complex, is phosphorylated, allowing CCT to dissociate and Gγ to bind. PhLP is released, exposing the binding site for Gα, allowing for formation of the final trimer at the endoplasmic reticulum, where it is targeted to the plasma membrane. Gγ subunits are known to be prenylated prior to addition to Gβ, which itself has not been found to be modified; this prenylation is thought to be involved in directing the interaction of the subunit both with membrane lipids and other proteins. The Gβγ complex is an essential element in the GPCR signaling cascade, it has two main states. When Gβγ is interacting with Gα it functions as a negative regulator. In the heterotrimer form, the Gβγ dimer increases the affinity of Gα for GDP, which causes the G protein to be in an inactive state. For the Gα subunit to become active, the nucleotide exchange must be induced by the GPCR.
Studies have shown that it is the Gβγ dimer that demonstrates specificity for the appropriate receptor and that the Gγ subunit enhances the interaction of the Gα subunit with the GPCR. The GPCR is activated by an extracellular ligand and subsequently activates the G protein heterotrimer by causing a conformational change in the Gα subunit; this causes the replacement of GDP with GTP as well as the physical dissociation of the Gα and the Gβγ complex. Once separated, both Gα and Gβγ are free to participate in their own distinct signaling pathways. Gβγ does not go through any conformational changes when it dissociates from Gα and it acts as a signaling molecule as a dimer; the Gβγ dimer has been found to interact with many different effector molecules by protein-protein interactions. Different combinations of the Gβ and Gγ subtypes can influence different effectors and work or synergistically with the Gα subunit. Gβγ signaling is diverse, inhibiting or activating many downstream events depending on its interaction with different effectors.
Researchers have discove
A diglyceride, or diacylglycerol, is a glyceride consisting of two fatty acid chains covalently bonded to a glycerol molecule through ester linkages. Two possible forms exist, 1,2-diacylglycerols and 1,3-diacylglycerols. DAGs can act as surfactants and are used as emulsifiers in processed foods. DAG-enriched oil has been investigated extensively as a fat substitute due to its ability to suppress the accumulation of body fat. Diglycerides are a minor component of many seed oils and are present at ~1–6%. Industrial production is achieved by a glycerolysis reaction between triglycerides and glycerol; the raw materials for this may be animal fats and oils. Diglycerides in a mix with monoglycerides, are common food additives used as emulsifiers; the values given in the nutritional labels for total fat, saturated fat, trans fat do not include those present in mono- and diglycerides. They are included in bakery products, ice cream, peanut butter, chewing gum, whipped toppings, confections and Pringles potato chips.
In biochemical signaling, diacylglycerol functions as a second messenger signaling lipid, is a product of the hydrolysis of the phospholipid phosphatidylinositol 4,5-bisphosphate by the enzyme phospholipase C that, through the same reaction, produces inositol trisphosphate. Although inositol trisphosphate diffuses into the cytosol, diacylglycerol remains within the plasma membrane, due to its hydrophobic properties. IP3 stimulates the release of calcium ions from the smooth endoplasmic reticulum, whereas DAG is a physiological activator of protein kinase C; the production of DAG in the membrane facilitates translocation of PKC from the cytosol to the plasma membrane. Diacylglycerol has been shown to exert some of its excitatory actions on vesicle release through interactions with the presynaptic priming protein family Munc13. Binding of DAG to the C1 domain of Munc13 increases the fusion competence of synaptic vesicles resulting in potentiated release. Diacylglycerol can be mimicked by the tumor-promoting compounds phorbol esters.
In addition to activating PKC, diacylglycerol has a number of other functions in the cell: a source for prostaglandins a precursor of the endocannabinoid 2-arachidonoylglycerol an activator of a subfamily of transient receptor potential canonical cation channels, TRPC3/6/7. Synthesis of diacylglycerol begins with glycerol-3-phosphate, derived from dihydroxyacetone phosphate, a product of glycolysis. Glycerol-3-phosphate is first acylated with acyl-coenzyme A to form lysophosphatidic acid, acylated with another molecule of acyl-CoA to yield phosphatidic acid. Phosphatidic acid is de-phosphorylated to form diacylglycerol. Dietary fat is composed of triglycerides; because triglycerides cannot be absorbed by the digestive system, triglycerides must first be enzymatically digested into monoacylglycerol, diacylglycerol, or free fatty acids. Diacylglycerol is a precursor to triacylglycerol, formed in the addition of a third fatty acid to the diacylglycerol under the catalysis of diglyceride acyltransferase.
Since diacylglycerol is synthesized via phosphatidic acid, it will contain a saturated fatty acid at the C-1 position on the glycerol moiety and an unsaturated fatty acid at the C-2 position. Diacylglycerol can be phosphorylated to phosphatidic acid by diacylglycerol kinase. Activation of PKC-θ by diacylglycerol may cause insulin resistance in muscle by decreasing IRS1-associated PI3K activity. Activation of PKCε by diacyglycerol may cause insulin resistance in the liver. Dietary sources of fatty acids, their digestion, transport in the blood and storage Lipid Monoglyceride Triglyceride
Peptides are short chains of amino acid monomers linked by peptide bonds. The covalent chemical bonds are formed when the carboxyl group of one amino acid reacts with the amino group of another; the shortest peptides are dipeptides, consisting of 2 amino acids joined by a single peptide bond, followed by tripeptides, etc. A polypeptide is a long and unbranched peptide chain. Hence, peptides fall under the broad chemical classes of biological oligomers and polymers, alongside nucleic acids and polysaccharides, etc. Peptides are distinguished from proteins on the basis of size, as an arbitrary benchmark can be understood to contain 50 or fewer amino acids. Proteins consist of one or more polypeptides arranged in a biologically functional way bound to ligands such as coenzymes and cofactors, or to another protein or other macromolecule, or to complex macromolecular assemblies. While aspects of the lab techniques applied to peptides versus polypeptides and proteins differ, the size boundaries that distinguish peptides from polypeptides and proteins are not absolute: long peptides such as amyloid beta have been referred to as proteins, smaller proteins like insulin have been considered peptides.
Amino acids that have been incorporated into peptides are termed "residues" due to the release of either a hydrogen ion from the amine end or a hydroxyl ion from the carboxyl end, or both, as a water molecule is released during formation of each amide bond. All peptides except cyclic peptides have an N-terminal and C-terminal residue at the end of the peptide. Many kinds of peptides are known, they have been categorized according to their sources and function. According to the Handbook of Biologically Active Peptides, some groups of peptides include plant peptides, bacterial/antibiotic peptides, fungal peptides, invertebrate peptides, amphibian/skin peptides, venom peptides, cancer/anticancer peptides, vaccine peptides, immune/inflammatory peptides, brain peptides, endocrine peptides, ingestive peptides, gastrointestinal peptides, cardiovascular peptides, renal peptides, respiratory peptides, opiate peptides, neurotrophic peptides, blood–brain peptides; some ribosomal peptides are subject to proteolysis.
These function in higher organisms, as hormones and signaling molecules. Some organisms produce peptides as antibiotics, such as microcins. Peptides have posttranslational modifications such as phosphorylation, sulfonation, palmitoylation and disulfide formation. In general, peptides are linear. More exotic manipulations do occur, such as racemization of L-amino acids to D-amino acids in platypus venom. Nonribosomal peptides are assembled by enzymes, not the ribosome. A common non-ribosomal peptide is glutathione, a component of the antioxidant defenses of most aerobic organisms. Other nonribosomal peptides are most common in unicellular organisms and fungi and are synthesized by modular enzyme complexes called nonribosomal peptide synthetases; these complexes are laid out in a similar fashion, they can contain many different modules to perform a diverse set of chemical manipulations on the developing product. These peptides are cyclic and can have complex cyclic structures, although linear nonribosomal peptides are common.
Since the system is related to the machinery for building fatty acids and polyketides, hybrid compounds are found. The presence of oxazoles or thiazoles indicates that the compound was synthesized in this fashion. Peptide fragments refer to fragments of proteins that are used to identify or quantify the source protein; these are the products of enzymatic degradation performed in the laboratory on a controlled sample, but can be forensic or paleontological samples that have been degraded by natural effects. Use of peptides received prominence in molecular biology for several reasons; the first is that peptides allow the creation of peptide antibodies in animals without the need of purifying the protein of interest. This involves synthesizing antigenic peptides of sections of the protein of interest; these will be used to make antibodies in a rabbit or mouse against the protein. Another reason is that techniques such as mass spectrometry enable the identification of proteins based on the peptide masses and sequence that result from their fragmentation.
Peptides have been used in the study of protein structure and function. For example, synthetic peptides can be used as probes to see where protein-peptide interactions occur- see the page on Protein tags. Inhibitory peptides are used in clinical research to examine the effects of peptides on the inhibition of cancer proteins and other diseases. For example, one of the most promising application is through peptides that target LHRH; these particular peptides act as an agonist, meaning that they bind to a cell in a way that regulates LHRH receptors. The process of inhibiting the cell receptors suggests that peptides could be beneficial in treating prostate cancer, but additional investigations and experiments are required before their cancer-fighting attributes can be considered definitive; the peptide families in this section are ribosomal peptides with hormonal activity. All of these peptides are synthesized by cells as longer "propeptides" or "proproteins" and truncated prior to exiting the cell.
They are released into the bloodstream. Magainin family Cecropin famil
Chromosome 20 is one of the 23 pairs of chromosomes in humans. Chromosome 20 spans around 63 million base pairs and represents between 2 and 2.5 percent of the total DNA in cells. Chromosome 20 was sequenced in 2001 and was reported to contain over 59 million base pairs representing 99.4% of the euchromatic DNA. Since due to sequencing improvements and fixes, the length of chromosome 20 has been updated to just over 63 million base pairs; the following are some of the gene count estimates of human chromosome 20. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies. Among various projects, the collaborative consensus coding sequence project takes an conservative strategy. So CCDS's gene number prediction represents a lower bound on the total number of human protein-coding genes; the following is a partial list of genes on human chromosome 20. For complete list, see the link in the infobox on the right; the following diseases are some of those related to genes on chromosome 20: Albright's hereditary osteodystrophy Arterial tortuosity syndrome Adenosine deaminase deficiency Alagille syndrome Fatal familial insomnia Galactosialidosis - CTSA Maturity onset diabetes of the young type 1 Neuronal ceroid lipofuscinosis Pantothenate kinase-associated neurodegeneration Transmissible spongiform encephalopathy Waardenburg syndrome National Institutes of Health.
"Chromosome 20". Genetics Home Reference. Retrieved 2017-05-06. "Chromosome 20". Human Genome Project Information Archive 1990–2003. Retrieved 2017-05-06