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Triple X Syndrome
Trisomy X, also known as triple X syndrome and characterized by the karyotype 47,XXX, is a chromosome disorder in which a female has an extra copy of the X chromosome. It is relatively common and occurs in 1 in 1,000 females, but is rarely diagnosed; fewer than 10% of those with the condition know they have it. Those who have symptoms can have learning disabilities, mild dysmorphic features such as hypertelorism (wide-spaced eyes) and clinodactyly (incurved little fingers), early menopause, and increased height. As the symptoms of trisomy X are often not serious enough to prompt a karyotype test, many cases of trisomy X are diagnosed before birth via prenatal screening tests such as amniocentesis. Most females with trisomy X live normal lives, although their socioeconomic status is reduced compared to the general population. Trisomy X occurs via a process called nondisjunction, in which normal cell division is interrupted and produces gametes with too many or too few chromoso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nondisjunction
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division (mitosis/meiosis). There are three forms of nondisjunction: failure of a pair of homologous chromosomes to separate in meiosis I, failure of sister chromatids to separate during meiosis II, and failure of sister chromatids to separate during mitosis. Nondisjunction results in daughter cells with abnormal chromosome numbers (aneuploidy). Calvin Bridges and Thomas Hunt Morgan are credited with discovering nondisjunction in ''Drosophila melanogaster'' sex chromosomes in the spring of 1910, while working in the Zoological Laboratory of Columbia University. Proof of the chromosome theory of heredity emerged from these early studies of chromosome non-disjunction. Types In general, nondisjunction can occur in any form of cell division that involves ordered distribution of chromosomal material. Higher animals have three distinct forms of such cell divisions: Meiosis I and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mosaic (genetics)
Mosaicism or genetic mosaicism is a condition in which a multicellular organism possesses more than one genetic line as the result of genetic mutation. This means that various genetic lines resulted from a single fertilized egg. Mosaicism is one of several possible causes of chimerism, wherein a single organism is composed of cells with more than one distinct genotype. Genetic mosaicism can result from many different mechanisms including chromosome nondisjunction, anaphase lag, and endoreplication. Anaphase lagging is the most common way by which mosaicism arises in the preimplantation embryo. Mosaicism can also result from a mutation in one cell during development, in which case the mutation will be passed on only to its daughter cells (and will be present only in certain adult cells). Somatic mosaicism is not generally inheritable as it does not generally affect germ cells. History In 1929, Alfred Sturtevant studied mosaicism in '' Drosophila'', a genus of fruit f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scoliosis
Scoliosis (: scolioses) is a condition in which a person's Vertebral column, spine has an irregular curve in the coronal plane. The curve is usually S- or C-shaped over three dimensions. In some, the degree of curve is stable, while in others, it increases over time. Mild scoliosis does not typically cause problems, but more severe cases can affect breathing and movement. Pain is usually present in adults, and can worsen with age. As the condition progresses, it may alter a person's life, and hence can also be considered a disability. It can be compared to kyphosis and lordosis, other abnormal curvatures of the spine which are in the sagittal plane (front-back) rather than the coronal (left-right). The cause of most cases is unknown, but it is believed to involve a combination of Genetics, genetic and environmental factors. Scoliosis most often occurs during growth spurts right before puberty. Risk factors include other affected family members. It can also occur due to anoth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asthma
Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath. A sudden worsening of asthma symptoms sometimes called an 'asthma attack' or an 'asthma exacerbation' can occur when allergens, pollen, dust, or other particles, are inhaled into the lungs, causing the bronchioles to constrict and produce mucus, which then restricts oxygen flow to the alveoli. These may occur a few times a day or a few times per week. Depending on the person, asthma symptoms may become worse at night or with exercise. Asthma is thought to be caused by a combination of genetic and environmental factors. Environmental factors include exposure to air pollution and allergens. Other potential triggers include medications such as aspirin and beta blockers. Diag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sleep Apnea
Sleep apnea (sleep apnoea or sleep apnœa in British English) is a sleep-related breathing disorder in which repetitive Apnea, pauses in breathing, periods of shallow breathing, or collapse of the upper airway during sleep results in poor ventilation and sleep disruption. Each pause in breathing can last for a few seconds to a few minutes and often occurs many times a night. A choking or snorting sound may occur as breathing resumes. Common symptoms include daytime sleepiness, snoring, and non restorative sleep despite adequate sleep time. Because the disorder disrupts normal sleep, those affected may experience sleepiness or feel tired during the day. It is often a chronic condition. Sleep apnea may be categorized as obstructive sleep apnea (OSA), in which breathing is interrupted by a blockage of air flow, central sleep apnea (CSA), in which regular unconscious breath simply stops, or a combination of the two. OSA is the most common form. OSA has four key contributors; these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sjögren Syndrome
Sjögren is a Swedish surname. Notable people with the surname include: * Anders Johan Sjögren (1794–1855), Finnish linguist, historian, ethnographer and explorer * Ann Mari Sjögren, Swedish fantasy artist and illustrator * Christer Sjögren, Swedish dansband and rock singer * Emil Sjögren (1853–1918), Swedish composer * Gunnar A. Sjögren (1920-1996), Swedish engineer who worked for Saab * Henrik Sjögren (1899–1986), Swedish ophthalmologist for whom Sjögren's syndrome was named, an autoimmune disorder leading to dry eyes and mouth * Hjalmar Sjögren, Swedish geologist and mineralogist * John C. Sjogren, United States Army soldier who received the Medal of Honor in World War II * John M. Sjogren American film director * Karin Sjögren (born 1960), Swedish curler, World and European champion * Katrin Sjögren (born 1966), Finnish politician from the Åland Islands * Peder Sjögren (1905–1966), Swedish writer who fought in the Spanish Civil War * Peter Sjögren, Swe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genitourinary
The genitourinary system, or urogenital system, are the sex organs of the reproductive system and the organs of the urinary system. These are grouped together because of their proximity to each other, their common embryological origin and the use of common pathways. Because of this, the systems are sometimes imaged together. In placental mammals (including humans), the male urethra goes through and opens into the penis while the female urethra and vagina empty through the vulva. The term "apparatus urogenitalis" was used in ''Nomina Anatomica'' (under splanchnologia) but is not used in the current ''Terminologia Anatomica''. Development The urinary and reproductive organs are developed from the intermediate mesoderm. The permanent organs of the adult are preceded by a set of structures that are purely embryonic and that, with the exception of the ducts, disappear almost entirely before the end of fetal life. These embryonic structures are on either side: the pronephros, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioulnar Synostosis
Radioulnar synostosis is a rare condition where there is an abnormal connection ( synostosis) between the radius and ulna bones of the forearm. This can be present at birth (congenital), when it is a result of a failure of the bones to form separately, or following an injury (post-traumatic). It typically causes restricted movement of the forearm, in particular rotation (pronation and supination), though is usually not painful unless it causes subluxation of the radial head. It can be associated with dislocation of the radial head which leads to limited elbow extension. Types Congenital Congenital radioulnar synostosis is rare, with approximately 350 cases reported in journals. It typically affects both sides (bilateral) and can be associated with other skeletal problems such as hip and knee abnormalities, finger abnormalities ( syndactyly or clinodactyly), or Madelung's deformity. It is sometimes part of known genetic syndromes such as Klinefelter syndrome (48,XXXY varian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palpebral Fissure
The palpebral fissure is the elliptic space between the medial and lateral canthi of the two open eyelids. In simple terms, it is the opening between the eyelids. In adult humans, this measures about 10 mm vertically and 30 mm horizontally. Variations Congenital dysmorphisms It can be reduced (short, "narrow") in horizontal size by fetal alcohol syndrome and in Williams syndrome. The chromosomal conditions trisomy 9 and trisomy 21 (Down syndrome) can cause the palpebral fissures to be upslanted, whereas Marfan syndrome can cause a downslant. An increase in vertical height can be seen in genetic disorders such as cri-du-chat syndrome. Acquired The fissure may be increased in vertical height in Graves' disease, which is manifested as Dalrymple's sign. It is seen in disorders such as cri-du-chat syndrome. In animal studies using four times the therapeutic concentration of the ophthalmic solution latanoprost, the size of the palpebral fissure can be increased. The condi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epicanthic Folds
An epicanthic fold or epicanthus is a skin fold of the upper eyelid that covers the inner corner (medial canthus) of the eye. However, variation occurs in the nature of this feature and the presence of "partial epicanthic folds" or "slight epicanthic folds" is noted in the relevant literature. Various factors influence whether epicanthic folds form, including ancestry, age, and certain medical conditions. The primary cause of the epicanthic fold is the hypertrophy of the preseptal portion of the orbicularis oculi muscle. Etymology ''Epicanthus'' means 'above the canthus', with epi-canthus being the Latinized form of the Ancient Greek : 'corner of the eye'. Classification Variation in the shape of the epicanthic fold has led to four types being recognised: * ''Epicanthus supraciliaris'' runs from the brow, curving downwards towards the lachrymal sac. * ''Epicanthus palpebralis'' begins above the upper tarsus and extends to the inferior orbital rim. * ''Epicanthus tarsa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dysmorphism
A dysmorphic feature is an abnormal difference in body structure. It can be an isolated finding in an otherwise normal individual, or it can be related to a congenital disorder, genetic syndrome or birth defect. Dysmorphology is the study of dysmorphic features, their origins and proper nomenclature. One of the key challenges in identifying and describing dysmorphic features is the use and understanding of specific terms between different individuals. Clinical geneticists and pediatricians are usually those most closely involved with the identification and description of dysmorphic features, as most are apparent during childhood. Dysmorphic features can vary from isolated, mild anomalies such as clinodactyly or synophrys to severe congenital anomalies, such as heart defects and holoprosencephaly. In some cases, dysmorphic features are part of a larger clinical picture, sometimes known as a sequence, syndrome or association. Recognizing the patterns of dysmorphic features is an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Craniofacial
Craniofacial surgery is a surgical subspecialty that deals with congenital and acquired deformities of the head, skull, face, neck, jaws and associated structures. Although craniofacial treatment often involves manipulation of bone, craniofacial surgery is not tissue-specific; craniofacial surgeons deal with bone, skin, nerve, muscle, teeth, and other related anatomy. Defects typically treated by craniofacial surgeons include craniosynostosis (isolated and syndromic), rare craniofacial clefts, acute and chronic sequelae of facial fractures, cleft lip and palate, micrognathia, Treacher Collins Syndrome, Apert's Syndrome, Crouzon's Syndrome, Craniofacial microsomia, microtia and other congenital ear anomalies, and many others. Training in craniofacial surgery requires completion of a Craniofacial surgery fellowship. Such fellowships are available to individuals who have completed residency in oral and maxillofacial surgery, plastic and reconstructive surgery, or ear, nose, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
