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Waardenburg Syndrome
Waardenburg syndrome is a group of rare genetic conditions characterised by at least some degree of congenital hearing loss and pigmentation deficiencies, which can include bright blue eyes (or one blue eye and one brown eye), a white forelock or patches of light skin. These basic features constitute type 2 of the condition; in type 1, there is also a wider gap between the inner corners of the eyes called telecanthus, or dystopia canthorum. In type 3, which is rare, the arms and hands are also malformed, with permanent finger contractures or fused fingers, while in type 4, the person also has Hirschsprung's disease. There also exist at least two types (2E and PCWH) that can result in central nervous system (CNS) symptoms such as developmental delay and muscle tone abnormalities. The syndrome is caused by mutations in any of several genes that affect the division and migration of neural crest cells during embryonic development (though some of the genes involved also affect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facies (medical)
In medical contexts, a facies is a distinctive facial expression or appearance associated with a specific medical condition. The term comes from Latin for "face". As a fifth declension noun, ''facies'' can be both singular and plural. Types Examples include: * Hippocratic facies – eyes are sunken, temples collapsed, nose is pinched with crusts on the lips, and the forehead is clammy * Moon face (also known as "Cushingoid facies") – Cushing's syndrome * Elfin facies – Williams syndrome * Potter facies – oligohydramnios * Mask like facies – parkinsonism * Leonine facies – lepromatous leprosy or craniometaphyseal dysplasia * Mitral facies – mitral stenosis * Amiodarone facies (deep blue discoloration around malar area and nose) * Acromegalic facies – acromegaly * Flat facies – Down syndrome * Marfanoid facies – Marfan's syndrome * Snarling facies – myasthenia gravis * Myotonic facies – myotonic dystrophy * Torpid facies – myxoedema * Mouse facie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurulation
Neurulation refers to the folding process in vertebrate embryos, which includes the transformation of the neural plate into the neural tube. The embryo at this stage is termed the neurula. The process begins when the notochord induces the formation of the central nervous system (CNS) by signaling the ectoderm germ layer above it to form the thick and flat neural plate. The neural plate folds in upon itself to form the neural tube, which will later differentiate into the spinal cord and the brain, eventually forming the central nervous system. Computer simulations found that cell wedging and differential proliferation are sufficient for mammalian neurulation. Different portions of the neural tube form by two different processes, called primary and secondary neurulation, in different species. * In primary neurulation, the neural plate creases inward until the edges come in contact and fuse. * In secondary neurulation, the tube forms by hollowing out of the interior of a solid p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unibrow
A unibrow (or jacco brow or monobrow; called synophrys in medicine) is a single eyebrow created when the two eyebrows meet in the middle above the bridge of the nose. The hair above the bridge of the nose is of the same color and thickness as the eyebrows, such that they converge to form one uninterrupted line of hair. History The word ''monobrow'' first appeared in print in 1968, and the adjectival form ''monobrowed'' followed in 1973, in Martin Amis' novel ''The Rachel Papers''. The first known use of the word ''unibrow'' was in 1981. Culture and beauty Oman A unibrow is considered as a sign of beauty by Baluchi Omanis. Its popularity causes women to draw a black line joining the brows as a part of their routine makeup to fake a unibrow. A study found the prevalence of synophrys to be at 11.87% in the Omani population. Tajikistan In Tajikistan, a unibrow is viewed as an attractive quality in both men and women. For women, it is associated with virginity and purity an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterochromia Iridum
Heterochromia is a variation in coloration. The term is most often used to describe color differences of the iris, but can also be applied to color variation of hair or skin. Heterochromia is determined by the production, delivery, and concentration of melanin (a pigment). It may be inherited, or caused by genetic mosaicism, chimerism, disease, or injury. It occurs in humans and certain breeds of domesticated animals. Heterochromia of the eye is called heterochromia iridum or heterochromia iridis. It can be complete or sectoral. In complete heterochromia, one iris is a different color from the other. In sectoral heterochromia, part of one iris is a different color from its remainder. In central heterochromia, there is a ring around the pupil or possibly spikes of different colors radiating from the pupil. Though multiple causes have been posited, the scientific consensus is that a lack of genetic diversity is the primary reason behind heterochromia, at least in domestic an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poliosis
Poliosis (also called poliosis circumscripta), is the decrease or absence of melanin (or colour) in head hair, eyebrows, eyelashes or any other hairy area. It is popularly known as white forelock when it affects hair directly above the forehead. This condition can cause single or, less commonly, multiple white patches on the hair. Some mistake these white patches for simple birth marks. In poliosis there is decreased or absent melanin in the hair bulbs of affected hair follicles; the melanocytes of the skin are usually not affected.} Associated medical conditions Poliosis occurs in several genetic syndromes such as piebaldism, Waardenburg syndrome, neurofibromatosis type I, and tuberous sclerosis. It can also occur in conditions such as vitiligo, Vogt–Koyanagi–Harada disease, alopecia areata, sarcoidosis, and in association with neoplasms and some medications. Popular culture It is sometimes called a Mallen streak, after a fictional family with hereditary poliosis. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensorineural Hearing Loss
Sensorineural hearing loss (SNHL) is a type of hearing loss in which the root cause lies in the inner ear or sensory organ (cochlea and associated structures) or the vestibulocochlear nerve (cranial nerve VIII). SNHL accounts for about 90% of reported hearing loss . SNHL is usually permanent and can be mild, moderate, severe, profound, or total. Various other descriptors can be used depending on the shape of the audiogram, such as high frequency, low frequency, U-shaped, notched, peaked, or flat. ''Sensory'' hearing loss often occurs as a consequence of damaged or deficient cochlear hair cells. Hair cells may be abnormal at birth or damaged during the lifetime of an individual. There are both external causes of damage, including infection, and ototoxic drugs, as well as intrinsic causes, including genetic mutations. A common cause or exacerbating factor in SNHL is prolonged exposure to environmental noise, or noise-induced hearing loss. Exposure to a single very loud noise s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petrus Johannes Waardenburg
Petrus Johannes Waardenburg (3 June 1886, Nijeveen, Drenthe – 23 September 1979) was a Dutch ophthalmologist, geneticist, and pioneer in the application of genetics to ophthalmology. Waardenburg syndrome is named after him. Biography Waardenburg studied medicine at the Utrecht University from 1904–11, and then trained in ophthalmology before receiving an MD for a dissertation on the hereditary basis of the physiological and pathological characteristics of the eye in 1913. Waardenburg was a regular contributor to eugenics publications. In 1932 Waardenburg suggested that Down syndrome might be the consequence of a chromosomal aberration, a fact which was confirmed after 27 years, by Jérôme Lejeune and his colleagues. From 1934 to 1940, Waardenburg was external university lecturer in medical genetics at Utrecht University. From 1931 to 1935 he was secretary of the Netherlands Ophthalmological Society. He was a founding member of the Netherlands Anthropogenetic Society a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autosomal Dominant
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and the second recessive. This state of having two different variants of the same gene on each chromosome is originally caused by a mutation in one of the genes, either new (''de novo'') or inherited. The terms autosomal dominant or autosomal recessive are used to describe gene variants on non-sex chromosomes (autosomes) and their associated traits, while those on sex chromosomes (allosomes) are termed X-linked dominant, X-linked recessive or Y-linked; these have an inheritance and presentation pattern that depends on the sex of both the parent and the child (see Sex linkage). Since there is only one copy of the Y chromosome, Y-linked traits cannot be dominant or recessive. Additionally, there are other forms of dominance such as incomple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SOX10
Transcription factor SOX-10 is a protein that in humans is encoded by the ''SOX10'' gene. Function This gene encodes a member of the SOX gene family, SOX (Testis-determining factor, SRY-related HMG-box) family of transcription factors involved in the regulation of embryonic development and determination of cell fate determination, cell fate. The encoded protein acts as a transcriptional activator after forming a protein complex with other proteins. This protein acts as a nucleocytoplasmic shuttle protein and is important for neural crest and peripheral nervous system development. In melanocyte, melanocytic cells, there is evidence that SOX10 gene expression may be regulated by Microphthalmia-associated transcription factor, MITF. Mutations Mutations in this gene are associated with Waardenburg–Shah syndrome and uveal melanoma. Immunostain SOX10 is used as an immunohistochemistry marker, being positive in: Topic Completed: 1 February 2014. Revised: 20 September 2019 *Neuro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MITF
Microphthalmia-associated transcription factor also known as class E basic helix-loop-helix protein 32 or bHLHe32 is a protein that in humans is encoded by the ''MITF'' gene. MITF is a basic helix-loop-helix leucine zipper transcription factor involved in lineage-specific pathway regulation of many types of cells including melanocytes, osteoclasts, and mast cells. The term "lineage-specific", since it relates to MITF, means genes or traits that are only found in a certain cell type. Therefore, MITF may be involved in the rewiring of signaling cascades that are specifically required for the survival and physiological function of their normal cell precursors. MITF, together with transcription factor EB (TFEB), TFE3 and TFEC, belong to a subfamily of related bHLHZip proteins, termed the MiT-TFE family of transcription factors. The factors are able to form stable DNA-binding homo- and heterodimers. The gene that encodes for MITF resides at the ''mi'' locus in mice, and its protum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAX3
The PAX3 (paired box gene 3) gene encodes a member of the paired box or PAX family of transcription factors. The PAX family consists of nine human (PAX1-PAX9) and nine mouse (Pax1-Pax9) members arranged into four subfamilies. Human PAX3 and mouse Pax3 are present in a subfamily along with the highly homologous human PAX7 and mouse Pax7 genes. The human PAX3 gene is located in the 2q36.1 chromosomal region, and contains 10 exons within a 100 kb region. Transcript splicing Alternative splicing and processing generates multiple PAX3 isoforms that have been detected at the mRNA level. PAX3e is the longest isoform and consists of 10 exons that encode a 505 amino acid protein. In other mammalian species, including mouse, the longest mRNAs correspond to the human PAX3c and PAX3d isoforms, which consist of the first 8 or 9 exons of the PAX3 gene, respectively. Shorter PAX3 isoforms include mRNAs that skip exon 8 (PAX3g and PAX3h) and mRNAs containing 4 or 5 exons (PAX3a and PAX3b). In l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
