|
McKusick–Kaufman Syndrome
McKusick–Kaufman syndrome (MKS) is a rare genetic condition caused by mutations in the '' MKKS'' gene, which affect how cells develop and function. It is named after Dr. Robert L. Kaufman and Victor McKusick, who studied the condition and helped identify key features. MKS can be difficult to recognize in infancy because it resembles Bardet–Biedl syndrome (BBS). While MKS mainly causes extra fingers or toes (postaxial polydactyly), fluid buildup in the vagina (hydrometrocolpos), and heart defects, BBS has more severe symptoms such as vision loss and obesity that usually appear later in life. MKS is most common in the Old Order Amish population, where it affects about 1 in 10,000 people. The syndrome was first discovered in this group through a genetic method called positional cloning, which helped scientists identify the ''MKKS'' gene as the cause of this condition. Its prevalence outside the Amish population remains unknown. Presentation Clinically, McKusick–Kaufman syndr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MKKS
McKusick–Kaufman/Bardet–Biedl syndromes putative chaperonin is a protein that in humans is encoded by the ''MKKS'' gene. This gene encodes a protein with sequence similarity to the chaperonin family. The encoded protein may have a role in protein processing in limb, cardiac and reproductive system development. Mutations in this gene have been observed in patients with Bardet–Biedl syndrome type 6 and McKusick–Kaufman syndrome McKusick–Kaufman syndrome (MKS) is a rare genetic condition caused by mutations in the '' MKKS'' gene, which affect how cells develop and function. It is named after Dr. Robert L. Kaufman and Victor McKusick, who studied the condition and helped .... Two transcript variants encoding the same protein have been identified for this gene. References External links GeneReviews/NIH/NCBI/UW entry on Bardet–Biedl syndromeGeneReviews/NIH/NCBI/UW entry on McKusick–Kaufman syndrome Further reading * * * * * * * * * * * * * * * * {{gene-20-s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptorchidism
Cryptorchidism, also known as undescended testis, is the failure of one or both testes to descend into the scrotum. The word is . It is the most common birth defect of the male genital tract. About 3% of full-term and 30% of premature infant boys are born with at least one undescended testis. However, about 80% of cryptorchid testes descend by the first year of life (the majority within three months), making the true incidence of cryptorchidism around 1% overall. Cryptorchidism may develop after infancy, sometimes as late as young adulthood, but that is exceptional. Cryptorchidism is distinct from monorchism, the condition of having only one testicle. Though the condition may occur on one or both sides, it more commonly affects the right testis. A testis absent from the normal scrotal position may be: # Anywhere along the "path of descent" from high in the posterior (retroperitoneal) abdomen, just below the kidney, to the inguinal ring # In the inguinal canal # Ectopic, havin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenotype
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological properties, and its behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code (its genotype) and the influence of environmental factors. Both factors may interact, further affecting the phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and again in his 1982 book '' The Extended Phenotype'' suggested that one can regard bird nests and other built structures such as caddisfly larva cases and beaver dams ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deletion (genetics)
In genetics, a deletion (also called gene deletion, deficiency, or deletion mutation) (sign: Δ) is a mutation (a genetic aberration) in which a part of a chromosome or a sequence of DNA is left out during DNA replication. Any number of nucleotides can be deleted, from a single base to an entire piece of chromosome. Some chromosomes have fragile spots where breaks occur, which result in the deletion of a part of the chromosome. The breaks can be induced by heat, viruses, radiation, or chemical reactions. When a chromosome breaks, if a part of it is deleted or lost, the missing piece of chromosome is referred to as a deletion or a deficiency. For synapsis to occur between a chromosome with a large intercalary deficiency and a normal complete homolog, the unpaired region of the normal homolog must loop out of the linear structure into a deletion or compensation loop. The smallest single base deletion mutations occur by a single base flipping in the template DNA, followed by te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insertion (genetics)
In genetics, an insertion (also called an insertion mutation) is the addition of one or more nucleotide base pairs into a DNA sequence. This can often happen in Microsatellite (genetics), microsatellite regions due to the DNA polymerase slipping. Insertions can be anywhere in size from one base pair incorrectly inserted into a DNA sequence to a section of one chromosome inserted into another. The mechanism of the smallest single base insertion mutations is believed to be through base-pair separation between the template and primer strands followed by non-neighbor base stacking, which can occur locally within the DNA polymerase active site. On a chromosome level, an ''insertion'' refers to the insertion of a larger sequence into a chromosome. This can happen due to unequal Chromosomal crossover, crossover during meiosis. N region addition is the addition of non-coded nucleotides during genetic recombination, recombination by terminal deoxynucleotidyl transferase. P nucleotide ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Missense Mutation
In genetics, a missense mutation is a point mutation in which a single nucleotide change results in a codon that codes for a different amino acid. It is a type of nonsynonymous substitution. Missense mutations change amino acids, which in turn alter proteins and may alter a protein's function or structure. These mutations may arise spontaneously from mutagens like UV radiation, tobacco smoke, an error in DNA replication, and other factors. Screening for missense mutations can be done by sequencing the genome of an organism and comparing the sequence to a reference genome to analyze for differences. Missense mutations can be repaired by the cell when there are errors in DNA replication by using mechanisms such as DNA proofreading and DNA mismatch repair, mismatch repair. They can also be repaired by using genetic engineering technologies or pharmaceuticals. Some notable examples of human diseases caused by missense mutations are Rett syndrome, cystic fibrosis, and Sickle cell disease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonsense Mutation
In genetics, a nonsense mutation is a point mutation in a sequence of DNA that results in a ''nonsense codon'', or a premature stop codon in the transcribed mRNA, and leads to a truncated, incomplete, and possibly nonfunctional protein product. Nonsense mutations are not always harmful; the functional effect of a nonsense mutation depends on many aspects, such as the location of the stop codon within the coding DNA. For example, the effect of a nonsense mutation depends on the proximity of the nonsense mutation to the original stop codon, and the degree to which functional subdomains of the protein are affected. As nonsense mutations leads to premature termination of polypeptide chains; they are also called chain termination mutations. Missense mutations differ from nonsense mutations since they are point mutations that exhibit a single nucleotide change to cause substitution of a different amino acid. A nonsense mutation also differs from a nonstop mutation, which is a point muta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers caused by exposure to ultraviolet radiation), which then may undergo error-prone repair (especially microhomology-mediated end joining), cause an error during other forms of repair, or cause an error during replication ( translesion synthesis). Mutations may also result from substitution, insertion or deletion of segments of DNA due to mobile genetic elements. Mutations may or may not produce detectable changes in the observable characteristics ( phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity. Mutati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cilium
The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike projection that extends from the surface of the much larger cell body. Eukaryotic flagella found on sperm cells and many protozoans have a similar structure to motile cilia that enables swimming through liquids; they are longer than cilia and have a different undulating motion. There are two major classes of cilia: ''motile'' and ''non-motile'' cilia, each with two subtypes, giving four types in all. A cell will typically have one primary cilium or many motile cilia. The structure of the cilium core, called the axoneme, determines the cilium class. Most motile cilia have a central pair of single microtubules surrounded by nine pairs of double microtubules called a 9+2 axoneme. Most non-motile cilia have a 9+0 axoneme that lacks the centr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytoskeleton
The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is composed of similar proteins in the various organisms. It is composed of three main components: microfilaments, intermediate filaments, and microtubules, and these are all capable of rapid growth and or disassembly depending on the cell's requirements. Cytoskeleton can perform many functions. Its primary function is to give the cell its shape and mechanical resistance to deformation, and through association with extracellular connective tissue and other cells it stabilizes entire tissues. The cytoskeleton can also contract, thereby deforming the cell and the cell's environment and allowing cells to migrate. Moreover, it is involved in many cell signaling pathways and in the uptake of extracellular material ( endocytosis), the segregation of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Complex
A protein complex or multiprotein complex is a group of two or more associated polypeptide chains. Protein complexes are distinct from multidomain enzymes, in which multiple active site, catalytic domains are found in a single polypeptide chain. Protein complexes are a form of protein quaternary structure, quaternary structure. Proteins in a protein complex are linked by non-covalent interactions, non-covalent protein–protein interactions. These complexes are a cornerstone of many (if not most) biological processes. The cell is seen to be composed of modular supramolecular complexes, each of which performs an independent, discrete biological function. Through proximity, the speed and selectivity of binding interactions between Enzyme, enzymatic complex and substrates can be vastly improved, leading to higher cellular efficiency. Many of the techniques used to enter cells and isolate proteins are inherently disruptive to such large complexes, complicating the task of determining ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaperonin
HSP60, also known as chaperonins (Cpn), is a family of heat shock proteins originally sorted by their 60kDa molecular mass. They prevent misfolding of proteins during stressful situations such as high heat, by assisting protein folding. HSP60 belong to a large class of molecules that assist protein folding, called molecular chaperones. Newly made proteins usually must fold from a linear chain of amino acids into a three-dimensional tertiary structure. The energy to fold proteins is supplied by non-covalent interactions between the amino acid side chains of each protein, and by solvent effects. Most proteins spontaneously fold into their most stable three-dimensional conformation, which is usually also their functional conformation, but occasionally proteins mis-fold. Molecular chaperones catalyze protein refolding by accelerating partial unfolding of misfolded proteins, aided by energy supplied by the hydrolysis of adenosine triphosphate (ATP). Chaperonin proteins may also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
