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- the means of connection between things linked in series (同)nexus
- a unit of length equal to 1/100 of a chain
- an interconnecting circuit between two or more locations for the purpose of transmitting and receiving data (同)data link
- a fastener that serves to join or connect; "the walls are held together with metal links placed in the wet mortar during construction" (同)linkup, tie, tie-in
- (computing) an instruction that connects one part of a program or an element on a list to another program or list
- that which is inherited; a title or property or estate that passes by law to the heir on the death of the owner (同)heritage
- (genetics) attributes acquired via biological heredity from the parents (同)hereditary pattern
- any attribute or immaterial possession that is inherited from ancestors; "my only inheritance was my mothers blessing"; "the worlds heritage of knowledge" (同)heritage
- hereditary succession to a title or an office or property (同)heritage
- (of genes) producing its characteristic phenotype only when its allele is identical
- the 24th letter of the Roman alphabet (同)x, ex
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- (鎖の)『輪』,環 / 鎖のようにつながったソーセージの一節 / (…と)つなぐ物(人),(…との)きずな,つながり《+『with』(『to』)+『名』》 / 《複数形で》=cuff links / …‘を'『つなぎ合わせる』,連結する;(…と)…‘を'つなぐ《+『名』+『with』(『to』)+『名』》 / (…と)結合する,つながる《+[『up』(『together』)]『with』+『名』》
- たいまつ
- 〈U〉『相続』,継承 / 〈C〉『遺産』,相続財産 / 〈C〉(両親・前任者・前代などから)受け継いだもの
- 後退する,退行の / (遺伝が)劣性の / 劣性遺伝形質
- Christ / Christian
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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/08/16 15:20:07」(JST)
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X-linked recessive inheritance
X-linked recessive inheritance is a mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be expressed in males (who are necessarily hemizygous for the gene mutation because they have one X and one Y chromosome) and in females who are homozygous for the gene mutation, see zygosity.
X-linked inheritance means that the gene causing the trait or the disorder is located on the X chromosome. Females have two X chromosomes, while males have one X and one Y chromosome. Carrier females who have only one copy of the mutation do not usually express the phenotype, although differences in X chromosome inactivation can lead to varying degrees of clinical expression in carrier females since some cells will express one X allele and some will express the other. The current estimate of sequenced X-linked genes is 499 and the total including vaguely defined traits is 983.[1]
Some scholars have suggested discontinuing the terms dominant and recessive when referring to X-linked inheritance due to the multiple mechanisms that can result in the expression of X-linked traits in females, which include cell autonomous expression, skewed X-inactivation, clonal expansion, and somatic mosaicism.[2]
Contents
- 1 Sex differences in phenotype/genotypes and frequency
- 2 Examples
- 2.1 Most common
- 2.2 Less common disorders
- 3 See also
- 4 References
- 5 External links
Sex differences in phenotype/genotypes and frequency
In humans, generally "men are affected and women are carriers" for two reasons. The first is the simple statistical fact that if the X-chromosomes is a population that carry a particular X-linked mutation at a frequency of 'f' (for example, 1%) then that will be the frequency that men are likely to express the mutation (since they have only one X), while women will express it at a frequency of f2 (for example 1% * 1% = 0.01%) since they have two X's and hence two chances to get the normal allele. Thus, X-linked mutations tend to be rare in women. The second reason for female rarity is that women who express the mutation must have two X chromosomes that carry the trait and they necessarily got one from their father, who would have also expressed the trait because he only had one X chromosome in the first place. If the trait lowers the probability of fathering a child or induces the father to only have children with women who aren't carriers (so as not to create daughters who are carriers rather than expressers and then only if no genetic screening is used) then women become even less likely to express the trait.
Examples
Most common
The most common X-linked recessive disorders are:[3]
- Red-green color blindness, a very common trait in humans and frequently used to explain X-linked disorders.[4] Between seven and ten percent of men and 0.49% to 1% of women are affected. Its commonness may be explained by its relatively benign nature. It is also known as daltonism.
- Hemophilia A, a blood clotting disorder caused by a mutation of the Factor VIII gene and leading to a deficiency of Factor VIII. It was once thought to be the "royal disease" found in the descendants of Queen Victoria. This is now known to have been Hemophilia B (see below).[5][6]
- Hemophilia B, also known as Christmas Disease,[7] a blood clotting disorder caused by a mutation of the Factor IX gene and leading to a deficiency of Factor IX. It is rarer than hemophilia A. As noted above, it was common among the descendants of Queen Victoria.
- Duchenne muscular dystrophy, which is associated with mutations in the dystrophin gene. It is characterized by rapid progression of muscle degeneration, eventually leading to loss of skeletal muscle control, respiratory failure, and death.
- Becker's muscular dystrophy, a milder form of Duchenne, which causes slowly progressive muscle weakness of the legs and pelvis.
- X-linked ichthyosis, a form of ichthyosis caused by a hereditary deficiency of the steroid sulfatase (STS) enzyme. It is fairly rare, affecting one in 2,000 to one in 6,000 males.[8]
- X-linked agammaglobulinemia (XLA), which affects the body's ability to fight infection. XLA patients do not generate mature B cells.[9] B cells are part of the immune system and normally manufacture antibodies (also called immunoglobulins) which defends the body from infections (the humoral response). Patients with untreated XLA are prone to develop serious and even fatal infections.[10]
- Glucose-6-phosphate dehydrogenase deficiency, which causes nonimmune hemolytic anemia in response to a number of causes, most commonly infection or exposure to certain medications, chemicals, or foods. Commonly known as "favism", as it can be triggered by chemicals existing naturally in broad (or fava) beans.[11]
Less common disorders
See also: X-linked mental retardation
Theoretically, a mutation in any of the genes on chromosome X may cause disease, but below are some notable ones, with short description of symptoms:
- Adrenoleukodystrophy; leads to progressive brain damage, failure of the adrenal glands and eventually death.
- Alport syndrome; glomerulonephritis, endstage kidney disease, and hearing loss.
- Androgen insensitivity syndrome; variable degrees of undervirilization and/or infertility in XY persons of either gender
- Barth syndrome; metabolism distortion, delayed motor skills, stamina deficiency, hypotonia, chronic fatigue, delayed growth, cardiomyopathy, and compromised immune system.
- Blue cone monochromacy; low vision acuity, color blindness, photophobia, infantile nystagmus.
- Centronuclear myopathy; where cell nuclei are abnormally located in skeletal muscle cells. In CNM the nuclei are located at a position in the center of the cell, instead of their normal location at the periphery.
- Charcot–Marie–Tooth disease (CMTX2-3); disorder of nerves (neuropathy) that is characterized by loss of muscle tissue and touch sensation, predominantly in the feet and legs but also in the hands and arms in the advanced stages of disease.
- Coffin–Lowry syndrome; severe mental retardation sometimes associated with abnormalities of growth, cardiac abnormalities, kyphoscoliosis as well as auditory and visual abnormalities.
- Fabry disease; A lysosomal storage disease causing anhidrosis, fatigue, angiokeratomas, burning extremity pain and ocular involvement.
- Hunter's Syndrome; potentially causing hearing loss, thickening of the heart valves leading to a decline in cardiac function, obstructive airway disease, sleep apnea, and enlargement of the liver and spleen.
- Hypohidrotic ectodermal dysplasia, presenting with hypohidrosis, hypotrichosis, hypodontia
- Kabuki syndrome; multiple congenital anomalies and mental retardation.
- Spinal and bulbar muscular atrophy; muscle cramps and progressive weakness
- Lesch-Nyhan syndrome; neurologic dysfunction, cognitive and behavioral disturbances including self-mutilation, and uric acid overproduction (hyperuricemia)
- Lowe Syndrome; hydrophthalmia, cataracts, intellectual disabilities, aminoaciduria, reduced renal ammonia production and vitamin D-resistant rickets
- Menkes disease; sparse and coarse hair, growth failure, and deterioration of the nervous system
- Nasodigitoacoustic syndrome; mishaped nose, brachydactyly of the distal phalanges, sensorineural deafness
- Nonsyndromic deafness and X-linked nonsyndromic deafness; hearing loss
- Norrie disease; cataracts, leukocoria along with other developmental issues in the eye
- Occipital horn syndrome; deformations in the skeleton
- Ocular albinism; lack of pigmentation in the eye
- Ornithine transcarbamylase deficiency; developmental delay and mental retardation. Progressive liver damage, skin lesions, and brittle hair may also be seen
- Siderius X-linked mental retardation syndrome; cleft lip and palate with mental retardation and facial dysmorphism, caused by mutations in the histone demethylase PHF8
- Simpson-Golabi-Behmel syndrome; coarse faces with protruding jaw and tongue, widened nasal bridge, and upturned nasal tip
- Spinal muscular atrophy caused by UBE1 gene mutation; weakness due to loss of the motor neurons of the spinal cord and brainstem
- Wiskott-Aldrich syndrome; eczema, thrombocytopenia, immune deficiency, and bloody diarrhea
- X-linked Severe Combined Immunodeficiency (SCID); infections, usually causing death in the first years of life
- X-linked sideroblastic anemia; skin paleness, fatigue, dizziness and enlarged spleen and liver.
See also
- Sex linkage
- X-linked dominant inheritance
References
- ^ OMIM X-linked Genes
- ^ Dobyns, William B.; Filauro, Allison; Tomson, Brett N.; Chan, April S.; Ho, Allen W.; Ting, Nicholas T.; Oosterwijk, Jan C.; Ober, Carole (2004). "Inheritance of most X-linked traits is not dominant or recessive, just X-linked". American Journal of Medical Genetics. 129A (2): 136. PMID 15316978. doi:10.1002/ajmg.a.30123.
- ^ GP Notebook - X-linked recessive disorders Retrieved on 5 Mars, 2009
- ^ OMIM Color Blindness, Deutan Series; CBD
- ^ Michael Price (8 October 2009). "Case Closed: Famous Royals Suffered From Hemophilia". ScienceNOW Daily News. AAAS. Retrieved 9 October 2009.
- ^ Rogaev, Evgeny I.; Grigorenko, Anastasia P.; Faskhutdinova, Gulnaz; Kittler, Ellen L. W.; Moliaka, Yuri K. (2009). "Genotype Analysis Identifies the Cause of the 'Royal Disease'". Science. 326 (5954): 817. Bibcode:2009Sci...326..817R. PMID 19815722. doi:10.1126/science.1180660.
- ^ "Hemophilia B". National Hemophilia Foundation.
- ^ Carlo Gelmetti; Caputo, Ruggero (2002). Pediatric Dermatology and Dermatopathology: A Concise Atlas. T&F STM. p. 160. ISBN 1-84184-120-X.
- ^ "X-linked Agammaglobulinemia: Immunodeficiency Disorders: Merck Manual Professional". Retrieved 2008-03-01.
- ^ XLA information by St. Jude Children's Hospital
- ^ http://patient.info/doctor/favism
External links
- X-linked diseases from the Wellcome Trust
|
Sex linkage: X-linked disorders
|
|
X-linked recessive
|
| Immune |
- Chronic granulomatous disease (CYBB)
- Wiskott–Aldrich syndrome
- X-linked severe combined immunodeficiency
- X-linked agammaglobulinemia
- Hyper-IgM syndrome type 1
- IPEX
- X-linked lymphoproliferative disease
- Properdin deficiency
|
| Hematologic |
- Haemophilia A
- Haemophilia B
- X-linked sideroblastic anemia
|
| Endocrine |
- Androgen insensitivity syndrome/Spinal and bulbar muscular atrophy
- KAL1 Kallmann syndrome
- X-linked adrenal hypoplasia congenita
|
| Metabolic |
- Amino acid: Ornithine transcarbamylase deficiency
- Oculocerebrorenal syndrome
- Dyslipidemia: Adrenoleukodystrophy
- Carbohydrate metabolism: Glucose-6-phosphate dehydrogenase deficiency
- Pyruvate dehydrogenase deficiency
- Danon disease/glycogen storage disease Type IIb
- Lipid storage disorder: Fabry's disease
- Mucopolysaccharidosis: Hunter syndrome
- Purine–pyrimidine metabolism: Lesch–Nyhan syndrome
- Mineral: Menkes disease/Occipital horn syndrome
|
| Nervous system |
- X-linked mental retardation: Coffin–Lowry syndrome
- MASA syndrome
- Alpha-thalassemia mental retardation syndrome
- Siderius X-linked mental retardation syndrome
- Eye disorders: Color blindness (red and green, but not blue)
- Ocular albinism (1)
- Norrie disease
- Choroideremia
- Other: Charcot–Marie–Tooth disease (CMTX2-3)
- Pelizaeus–Merzbacher disease
- SMAX2
|
| Skin and related tissue |
- Dyskeratosis congenita
- Hypohidrotic ectodermal dysplasia (EDA)
- X-linked ichthyosis
- X-linked endothelial corneal dystrophy
|
| Neuromuscular |
- Becker's muscular dystrophy/Duchenne
- Centronuclear myopathy (MTM1)
- Conradi–Hünermann syndrome
- Emery–Dreifuss muscular dystrophy 1
|
| Urologic |
- Alport syndrome
- Dent's disease
- X-linked nephrogenic diabetes insipidus
|
| Bone/tooth |
- AMELX Amelogenesis imperfecta
|
| No primary system |
- Barth syndrome
- McLeod syndrome
- Smith–Fineman–Myers syndrome
- Simpson–Golabi–Behmel syndrome
- Mohr–Tranebjærg syndrome
- Nasodigitoacoustic syndrome
|
|
|
X-linked dominant
|
- X-linked hypophosphatemia
- Focal dermal hypoplasia
- Fragile X syndrome
- Aicardi syndrome
- Incontinentia pigmenti
- Rett syndrome
- CHILD syndrome
- Lujan–Fryns syndrome
- Orofaciodigital syndrome 1
- Craniofrontonasal dysplasia
|
|
[Female X-linked disorders]
- https://www.nlm.nih.gov/medlineplus/ency/article/002051.htm
UpToDate Contents
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English Journal
- Understanding of Genetic Inheritance among Xhosa-Speaking Caretakers of Children with Hemophilia.
- Solomon G, Greenberg J, Futter M, Vivian L, Penn C.SourceDepartment of Clinical and Laboratory Sciences, Division of Human Genetics, University of Cape Town, Cape Town, South Africa, gabriele.solomon@uct.ac.za.
- Journal of genetic counseling.J Genet Couns.2012 Oct;21(5):726-40. Epub 2012 Mar 10.
- Hemophilia A and B are X-linked recessive inherited bleeding disorders that have a profound impact on the family of affected individuals. Education is vital to enable women to appreciate the implications of being a carrier and the implications for a prospective child. Prior research has shown that c
- PMID 22407306
Japanese Journal
- 岡 政史,野津 寛大,飯島 一誠,松尾 雅文
- 日本小児腎臓病学会雑誌 = Japanese journal of pediatric nephrology 23(1), 8-12, 2010-04-15
- Alport症候群 (AS) は感音性難聴を伴う遺伝性進行性腎疾患である。高頻度に末期腎不全に至るとされ臨床的に重要な疾患であるが，その臨床像，自然予後は十分には解明されていない。今回，分子遺伝学的特徴および近年報告された家族性良性血尿症候群との関連について，常染色体性Alport症候群を中心に概要をまとめる。
- NAID 10026412082
- 野津 寛大,飯島 一誠,松尾 雅文
- 日本小児腎臓病学会雑誌 = Japanese journal of pediatric nephrology 21(2), 117-121, 2008-11-15
- … 中でも最も頻度の高い，X染色体連鎖型Alport症候群を中心に概要をまとめる。 …
- NAID 10025170337
Related Links
- A mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be expressed in males who are hemizygous for the gene mutation (i.e., they have only one X chromosome) and in ...
- X-Linked Recessive Inheritance X-Linked Recessive Inheritance X-linked recessive disease usually occurs in males who have inherited a recessive X-linked mutation from their mother. Rarely, the disease may be seen in females who ...
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- X-linked recessive inheritance, X-linked recessive
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- sex-linked recessive inheritance
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X連鎖劣性遺伝 X-linked recessive inheritance
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キサントシン, xanthosine