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Dysmelia
Dysmelia (from the Greek (), "bad" + (), "limb" + English suffix -ia) is a congenital disorder of a limb resulting from a disturbance in embryonic development.(2006) Dysmelia (Limb Deficiency/Reduction). pp 312-322. In: Atlas of Genetic Diagnosis and Counseling. Humana Press. Types Dysmelia can refer to * missing (aplasia) limbs: amelia, oligodactyly, congenital amputation e.g. tibial or radial aplasia * malformation of limbs: shortening (micromelia, rhizomelia or mesomelia), ectrodactyly, phocomelia, meromelia, syndactyly, brachydactyly, club foot * too many limbs: polymelia, polydactyly, polysyndactyly * others: tetraamelia, hemimelia, symbrachydactyly Occurrence rate Birth defects involving limbs occur in 1 per 1000. Causes Dysmelia can be caused by * Inheritance of abnormal genes, e.g. polydactyly, ectrodactyly or brachydactyly, symptoms of deformed limbs then often occur in combination with other symptoms (syndromes) * external causes during pregnancy (thus not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amniotic Band Syndrome
Constriction ring syndrome (CRS) is a congenital disorder with unknown cause. Because of the unknown cause there are many different, and sometimes incorrect names. It is a malformation due to intrauterine bands or rings that give deep grooves in, most commonly, distal extremities like fingers and toes. In rare cases the constriction ring can form around other parts of the fetus and cause amputation or even intrauterine death. The anatomy proximal to the site of constriction (or amputation) is developmentally normal. CRS can be associated with other malformations with club foot being most common. The precise configuration of the bands, lymphedema, and character of the amputations are not predictable and vary with each individual patient. Also more than one extremity is usually affected, and it is rare for only one ring to present as an isolated malformation with no other manifestation of this syndrome. Signs and symptoms The constriction of appendages by amniotic bands may result in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amelia (birth Defect)
Amelia is the birth defect of lacking one or more limbs. It can also result in a shrunken or deformed limb. The term may be modified to indicate the number of legs or arms missing at birth, such as tetra-amelia for the absence of all four limbs. A related term is meromelia, which is the partial absence of a limb or limbs. The term is from Greek ἀ- "lack of" plus μέλος (plural: μέλεα or μέλη) "limb" Symptoms The diagnosis of tetra-amelia syndrome is established clinically and can be made on routine prenatal ultrasonography. WNT3 is the only gene known to be associated with tetra-amelia syndrome. Molecular genetic testing on a clinical basis can be used to diagnose the incidence of the syndrome. The mutation detection frequency is unknown as only a limited number of families have been studied. Affected infants are often stillborn or die shortly after birth. Description Amelia may be present as an isolated defect, but it is often associated with major malformations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymelia
Polymelia is a birth defect in which an affected individual has more than the usual number of limbs. It is a type of dysmelia. In humans and most land-dwelling vertebrates, this means having five or more limbs. The extra limb is most commonly shrunken and/or deformed. The term is from Greek πολυ- "many", μέλεα "limbs". Sometimes an embryo started as conjoined twins, but one twin degenerated completely except for one or more limbs, which end up attached to the other twin. Sometimes small extra legs between the normal legs are caused by the body axis forking in the dipygus condition. Notomelia (from Greek for "back-limb-condition") is polymelia where the extra limb is rooted along or near the midline of the back. Notomelia has been reported in Angus cattle often enough to be of concern to farmers. Cephalomelia (from Greek for "head-limb-condition") is polymelia where the extra limb is rooted on the head. Origin Tetrapod legs evolved in the Devonian or Carboniferous geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brachydactyly
Brachydactyly (Greek βραχύς = "short" plus δάκτυλος = "finger"), is a medical term which literally means "short finger". The shortness is relative to the length of other long bones and other parts of the body. Brachydactyly is an inherited, dominant trait. It most often occurs as an isolated dysmelia, but can also occur with other anomalies as part of many congenital syndromes. Brachydactyly may also be a signal that one is at risk for congenital heart disease due to the association between congenital heart disease and carpenter's syndrome and the link between carpenter's syndrome and brachydactyly Nomograms for normal values of finger length as a ratio to other body measurements have been published. In clinical genetics, the most commonly used index of digit length is the dimensionless ratio of the length of the third (middle) finger to the hand length. Both are expressed in the same units (centimeters, for example) and are measured in an open hand from the finger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malformation
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth defects are divided into two main types: structural disorders in which problems are seen with the shape of a body part and functional disorders in which problems exist with how a body part works. Functional disorders include metabolic and degenerative disorders. Some birth defects include both structural and functional disorders. Birth defects may result from genetic or chromosomal disorders, exposure to certain medications or chemicals, or certain infections during pregnancy. Risk factors include folate deficiency, drinking alcohol or smoking during pregnancy, poorly controlled diabetes, and a mother over the age of 35 years old. Many are believed to involve multiple factors. Birth defects may be visib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligodactyly
Oligodactyly (from Ancient Greek ''oligos'' 'few' and δάκτυλος ''daktylos'' 'finger') is the presence of fewer than five fingers or toes on a hand or foot.Medical terms Dictionary Accessed February 16, 2010 It is quite often incorrectly called ''hypodactyly''; the prefixes hypo- and hyper- are used for scales (e.g. in |
Phocomelia
Phocomelia is a condition that involves malformations of human arms and legs. Although many factors can cause phocomelia, the prominent roots come from the use of the drug thalidomide and from genetic inheritance. Occurrence in an individual results in various abnormalities to the face, limbs, ears, nose, vessels and many other underdevelopments. Although operations may improve some abnormalities, many are not surgically treatable due to the lack of nerves and other related structures. The term is from Ancient Greek φώκη ''phōkē'', "seal (animal)" + ''-o-'' interfix + μέλος ''melos'', "limb" + English suffix ''-ia''). Phocomelia is an extremely rare congenital disorder involving malformation of the limbs (dysmelia). Étienne Geoffroy Saint-Hilaire coined the term in 1836. Signs and symptoms The symptoms of phocomelia syndrome are undeveloped limbs and absent pelvic bones; however, various abnormalities can occur to the limbs and bones. Usually the upper limbs are n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congenital Disorder
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth defects are divided into two main types: structural disorders in which problems are seen with the shape of a body part and functional disorders in which problems exist with how a body part works. Functional disorders include metabolic and degenerative disorders. Some birth defects include both structural and functional disorders. Birth defects may result from genetic or chromosomal disorders, exposure to certain medications or chemicals, or certain infections during pregnancy. Risk factors include folate deficiency, drinking alcohol or smoking during pregnancy, poorly controlled diabetes, and a mother over the age of 35 years old. Many are believed to involve multiple factors. Birth defects may be vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limb (anatomy)
A limb (from the Old English ''lim'', meaning "body part") or leg is a jointed, muscled appendage that tetrapod vertebrates use for weight-bearing and terrestrial locomotion such as walking, running and jumping, for paddle-swimming, or for grasping and climbing. The distalmost portion of a limb is known as its extremity. The limbs' bony endoskeleton, known as the appendicular skeleton, is homologous among all tetrapods. All tetrapods have four limbs that are organized into two bilaterally symmetrical pairs, with one pair at each end of the torso. The cranial pair are known as the forelimbs or ''front legs'', and the caudal pair the hindlimbs or ''back legs''. In animals with more upright posture (mainly hominid primates, particularly humans), the forelimbs and hindlimbs are often called upper and lower limbs, respectively. The fore-/upper limbs are connected to the thoracic cage via the shoulder girdles, and the hind-/lower limbs are connected to the pelvis via the hip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Club Foot
Clubfoot is a birth defect where one or both feet are rotated inward and downward. Congenital clubfoot is the most common congenital malformation of the foot with an incidence of 1 per 1000 births. In approximately 50% of cases, clubfoot affects both feet, but it can present unilaterally causing one leg or foot to be shorter than the other. Most of the time, it is not associated with other problems. Without appropriate treatment, the foot deformity will persist and lead to pain and impaired ability to walk, which can have a dramatic impact on the quality of life. The exact cause is usually not identified. Both genetic and environmental factors are believed to be involved. There are two main types of congenital clubfoot: idiopathic (80% of cases) and secondary clubfoot (20% of cases). The idiopathic congenital clubfoot is a multifactorial condition that includes environmental, vascular, positional, and genetic factors. There appears to be hereditary component for this birth d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syndrome
A syndrome is a set of medical signs and symptoms which are correlated with each other and often associated with a particular disease or disorder. The word derives from the Greek σύνδρομον, meaning "concurrence". When a syndrome is paired with a definite cause this becomes a disease. In some instances, a syndrome is so closely linked with a pathogenesis or cause that the words ''syndrome'', ''disease'', and ''disorder'' end up being used interchangeably for them. This substitution of terminology often confuses the reality and meaning of medical diagnoses. This is especially true of inherited syndromes. About one third of all phenotypes that are listed in OMIM are described as dysmorphic, which usually refers to the facial gestalt. For example, Down syndrome, Wolf–Hirschhorn syndrome, and Andersen–Tawil syndrome are disorders with known pathogeneses, so each is more than just a set of signs and symptoms, despite the ''syndrome'' nomenclature. In other instances, a synd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genes
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
