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Polysyndactyly
Polysyndactyly is a congenital anomaly, combining polydactyly and syndactyly, in which affected individuals have an extra finger or toe that is connected, via fusing or webbing, to an adjacent digit. __TOC__ Signs and symptoms Presentations of polysyndactyly vary in location and size of the duplicated digit, and in the extent of webbing between digits. The extra digit is most commonly postaxial, on the same side as the pinky or little toe. Preaxial polysyndactyly, in which the duplicated digit is on the side of the thumb or big toe, is less common. Crossed polysyndactyly, in which polysyndactyly is present on the hand and foot, and is preaxial on one and postaxial on the other, is extremely rare and often occurs with other genetic disorders. Polysyndactyly may be classified by the level of duplication. The extra digit may be small and comprise only soft tissue, but usually includes at least one bone, most commonly the distal and middle phalanges. Partial or complete duplica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greig Cephalopolysyndactyly Syndrome
Greig cephalopolysyndactyly syndrome is a disorder that affects development of the limbs, head, and face. The features of this syndrome are highly variable, ranging from very mild to severe. People with this condition typically have one or more extra fingers or toes (polydactyly) or an abnormally wide thumb or big toe (hallux). Presentation The skin between the fingers and toes may be fused (cutaneous syndactyly). This disorder is also characterized by widely spaced eyes (ocular hypertelorism), an abnormally large head size (macrocephaly), and a high, prominent forehead. Rarely, affected individuals may have more serious medical problems including seizures and developmental delay. Pathophysiology Greig cephalopolysyndactyly syndrome is a chromosomal condition related to chromosome 7. Mutations in the ''GLI3'' gene cause Greig cephalopolysyndactyly syndrome. The ''GLI3'' gene provides instructions for making a protein that controls gene expression, which is a process that regul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GLI3
Zinc finger protein GLI3 is a protein that in humans is encoded by the ''GLI3'' gene. This gene encodes a protein that belongs to the C2H2-type zinc finger proteins subclass of the Gli family. They are characterized as DNA-binding transcription factors and are mediators of Sonic hedgehog (Shh) signaling. The protein encoded by this gene localizes in the cytoplasm and activates patched Drosophila homolog (PTCH1) gene expression. It is also thought to play a role during embryogenesis. Role in development Gli3 is a known transcriptional repressor but may also have a positive transcriptional function. Gli3 represses dHand and Gremlin, which are involved in developing digits. There is evidence that Shh-controlled processing (e.g., cleavage) regulates transcriptional activity of Gli3 similarly to that of Ci. Gli3 mutant mice have many abnormalities including CNS and lung defects and limb polydactyly. In the developing mouse limb bud, Gli3 derepression predominantly regulate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polydactyly
Polydactyly or polydactylism (), also known as hyperdactyly, is an anomaly in humans and animals resulting in supernumerary fingers and/or toes. Polydactyly is the opposite of oligodactyly (fewer fingers or toes). Signs and symptoms In humans/animals this condition can present itself on one or both hands or feet. The extra digit is usually a small piece of soft tissue that can be removed. Occasionally it contains bone without joints; rarely it may be a complete functioning digit. The extra digit is most common on the ulnar (little finger) side of the hand, less common on the radial (thumb) side, and very rarely within the middle three digits. These are respectively known as postaxial (little finger), preaxial (thumb), and central (ring, middle, index fingers) polydactyly. The extra digit is most commonly an abnormal fork in an existing digit, or it may rarely originate at the wrist as a normal digit does. The incidence of congenital deformities in newborns is approximately 2%, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carpenter Syndrome
Carpenter syndrome, also called acrocephalopolysyndactyly type II, is an extremely rare autosomal recessive congenital disorder characterized by craniofacial malformations, obesity, syndactyly, and polydactyly. Acrocephalopolysyndactyly is a variation of acrocephalosyndactyly that presents with polydactyly. It was first characterized in 1909, and is named for George Alfred Carpenter. Presentation Carpenter syndrome presents several features: * Turricephaly – tower-shaped skull * Polydactyly – additional digits (fingers and toes) * Syndactyly – fused digits * Obesity * Reduced height * Undescended testes Intellectual disability is also common with the disorder, although some patients may have average intellectual capacity. Description Carpenter syndrome belongs to a rare genetic disorder known as acrocephalosyndactyly, (ACPS) (RN, 2007). There were originally five types of ACPS, but this number has been decreased because they have been found to be closely related to one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syndactyly
Syndactyly is a condition wherein two or more digits are fused together. It occurs normally in some mammals, such as the siamang and diprotodontia, but is an unusual condition in humans. The term is from Greek σύν, ''syn'' 'together' and δάκτυλος, ''daktulos'' 'finger'. Classification Syndactyly can be simple or complex. * In simple syndactyly, adjacent fingers or toes are joined by soft tissue. * In complex syndactyly, the bones of adjacent digits are fused. The kangaroo exhibits complex syndactyly. Syndactyly can be complete or incomplete. * In complete syndactyly, the skin is joined all the way to the tip of the involved digits. * In incomplete syndactyly, the skin is only joined part of the distance to the tip of the involved digits. Complex syndactyly occurs as part of a syndrome (such as Apert syndrome) and typically involves more digits than simple syndactyly. Fenestrated syndactyly, also known as acrosyndactyly or terminal syndactyly, means the skin is joine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pallister–Hall Syndrome
Pallister–Hall syndrome (abbreviated PHS) is a disorder that affects the development of many parts of the body. It is named for Judith Hall and Philip Pallister. Presentation Most people with this condition have extra fingers and/or toes (polydactyly), and the skin between some fingers or toes may be fused (cutaneous syndactyly). An abnormal growth in the brain called a hypothalamic hamartoma is characteristic of this disorder. In many cases, these growths do not cause any medical problems; however, some hypothalamic hamartomas lead to seizures or hormone abnormalities that can be life-threatening in infancy. Other features of Pallister–Hall syndrome include a malformation of the airway called a bifid epiglottis, laryngeal cleft, an obstruction of the anal opening (imperforate anus), and kidney abnormalities. Although the signs and symptoms of this disorder vary from mild to severe, only a small percentage of affected people have serious complications. Seizures As noted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thumb
The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thumb is ''pollex'' (compare ''hallux'' for big toe), and the corresponding adjective for thumb is ''pollical''. Definition Thumb and fingers The English word ''finger'' has two senses, even in the context of appendages of a single typical human hand: # Any of the five terminal members of the hand. # Any of the four terminal members of the hand, other than the thumb Linguistically, it appears that the original sense was the first of these two: (also rendered as ) was, in the inferred Proto-Indo-European language, a suffixed form of (or ), which has given rise to many Indo-European-family words (tens of them defined in English dictionaries) that involve, or stem from, concepts of fiveness. The thumb shares the following with each of the o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syndactyly
Syndactyly is a condition wherein two or more digits are fused together. It occurs normally in some mammals, such as the siamang and diprotodontia, but is an unusual condition in humans. The term is from Greek σύν, ''syn'' 'together' and δάκτυλος, ''daktulos'' 'finger'. Classification Syndactyly can be simple or complex. * In simple syndactyly, adjacent fingers or toes are joined by soft tissue. * In complex syndactyly, the bones of adjacent digits are fused. The kangaroo exhibits complex syndactyly. Syndactyly can be complete or incomplete. * In complete syndactyly, the skin is joined all the way to the tip of the involved digits. * In incomplete syndactyly, the skin is only joined part of the distance to the tip of the involved digits. Complex syndactyly occurs as part of a syndrome (such as Apert syndrome) and typically involves more digits than simple syndactyly. Fenestrated syndactyly, also known as acrosyndactyly or terminal syndactyly, means the skin is joine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Expressivity (genetics)
In genetics, expressivity is the degree to which a phenotype is expressed by individuals having a particular genotype. (Alternately, it may refer to the expression of particular gene by individuals having a certain phenotype.) Expressivity is related to the ''intensity'' of a given phenotype; it differs from penetrance, which refers to the ''proportion'' of individuals with a particular genotype that actually express the phenotype. Variable expressivity Variable expressivity refers to the degree in which a genotype is phenotypically expressed. For example, multiple people with the same disease can have the same genotype but one may express more severe symptoms, while another carrier may appear normal. This variation in expression can be affected by modifier genes, epigenetic factors or the environment. Modifier genes can alter the expression of other genes in either an additive or multiplicative way. Meaning the phenotype that is observed can be a result of two different alleles b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penetrance
Penetrance in genetics is the proportion of individuals carrying a particular variant (or allele) of a gene (the genotype) that also express an associated trait (the phenotype). In medical genetics, the penetrance of a disease-causing mutation is the proportion of individuals with the mutation who exhibit clinical symptoms among all individuals with such mutation. For example, if a mutation in the gene responsible for a particular autosomal dominant disorder has 95% penetrance, then 95% of those with the mutation will develop the disease, while 5% will not. A condition, most commonly inherited in an autosomal dominant manner, is said to show complete penetrance if clinical symptoms are present in all individuals who have the disease-causing mutation. A condition which shows complete penetrance is neurofibromatosis type 1 – every person who has a mutation in the gene will show symptoms of the condition. The penetrance is 100%. Common examples used to show degrees of penetrance are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Ultrasound
Medical ultrasound includes diagnostic techniques (mainly imaging techniques) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics (e.g. distances and velocities) or to generate an informative audible sound. Its aim is usually to find a source of disease or to exclude pathology. The usage of ultrasound to produce visual images for medicine is called medical ultrasonography or simply sonography. The practice of examining pregnant women using ultrasound is called obstetric ultrasonography, and was an early development of clinical ultrasonography. Ultrasound is composed of sound waves with frequencies which are significantly higher than the range of human hearing (>20,000 Hz). Ultrasonic images, also known as sonograms, are created by sending pulses of ultrasound into tissue using a pr ... [...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. However, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
