| fra(X) | fragile X chromosome, fragile X syndrome |
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| AFRAX | autism-fragile X [syndrome] |
| FHIT | fragile histidine triad [gene] |
| FMR | fragile site mental retardation [syndrome]; Friend-Moloney-Rauscher [antigen] |
| FRAX | fragile [chromosome] X |
| FS | Fragile Sites |
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| Fra(X) | Fragile X |
| FMR1 | Fragile X Mental Retardation gene 1 |
| FMR-1 | Fragile X Mental Retardation-1 |
| FMRP | Fragile X mental retardation 1 protein |
| fragile x chromosome | X chromosome with a fragile site associated with a frequent form of mental retardation. The fragile X chromosome was first sighted by Herbert A. Lubs in 1969. The fragile X is also called FRAXA (the second A signifies it was the first FRAgile site found on the X chromosome). It is due a trinucleotide repeat (a recurring motif of 3 bases) in the DNA at that spot. (12 Dec 1998) |
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| fragile X syndrome | <syndrome> most frequent cause of mental retardation. There is an expanded trinucleotide repeat CGG in the fra(X) gene. There is usually a constricted section on the long arm of the X chromosome. After puberty these patients often exhibit large prominent ears, long narrow face, coarse facial features and macroorchidism. Mental retardation in males is characteristic although the manifestations of the syndrome are highly variable. A preponderance of males are affected but it also affects 30% of carrier females and about 20% of obligate carrier males are not affected. The complexity in the inheritance pattern comes from the fact that these obligate carrier males (transmitting males) pass on the mutation to all their daughters (unaffected). most of the sons of carrier females with the mutation are mentally retarded but of their daughters, only 1/3 are retarded while 1/3 are borderline retarded and 1/3 are normal. Penetrance of the disease is variable within families and among siblings. Another unique characteristic of this syndrome, which is referred to as the Sherman Paradox is the fact that the risk of a family member being abnormal when gene-positive depends on the position of the proband in the pedigree. Sons of phenotypically normal but transmitting males have no risk of being mentally affected, but grandsons and great-grandsons of the transmitting a male have a much higher risk of mental retardation (40% and 50%, respectively). On the other hand, if the carrier female expresses the mental handicap her sons have a 50% risk of mental retardation. The classical method of confirming diagnosis is culture of lymphocytes in a folate-free medium (or supplemented with trimethoprim, methotrexate or FUdR) and microscopic detection of the fragile site (Xq27.3). Expression is seen in less than 50% of the cells of affected individuals but the test is not applicable to carrier detection as there is a high false negative rate (60%). The fragile-X gene (FMR-1), which contains tandemly repeated trinucleotide sequences (CGG repeats) on its 5' end, can be detected with PCR or Southern blot techniques. Normal controls show 6-50 CGG repeats, whereas mutation in affected males or heterozygous females can contain as many as 1,000 CGG repeat units. The test is indicated for individuals with compatible mental retardation, developmental delays or autism, or for those that have a family history of the syndrome. It is also indicated for prenatal detection in offspring of carrier females. Inheritance: sex-linked. Incidence: 1 in 1200 males and 1 in 2500 females. (17 Dec 1997) |
| chromosome fragile sites | Heritable sensitive regions of chromosomes which show up in vitro as non-staining bands. They are associated with chromosome breakage and other aberrations, and, when located on sex chromosomes, they produce phenotypic abnormalities. No abnormal phenotype has been definitely identified with autosomal fragile sites, but some rare autosomal recessive disorders may be due to homozygosity for fragile sites. Fragile sites are designated by the letters "fra" followed by the designation for the specific chromosome and locus. (12 Dec 1998) |
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| syndrome, fragile x | The most common heritable form of mental retardation. Fragile x syndrome is due to mutation (changes) at the fragile x site and so perforce is x-linked (carried on the x chromosome). Although it is usually more severe in males than females, the syndrome is due to a dynamic mutation (a trinucleotide repeat) that can change in length and hence in severity from generation to generation, from person to person, and even within a given person. The fragile x syndrome is also known as the martin-bell syndrome in honor of their discovery of it in 1943. (12 Dec 1998) |
| fragile site | Places on chromosomes that tend to break more often than other places. These places also tend to be where chromosomal translocations (a type of chromosomal mutation) occur. (09 Oct 1997) |
Synonyms : FMRP Protein, Fragile X Mental Retardation-1 Protein, Fragile X Mental Retardation 1 Protein
Synonyms : FRAXA Syndromes, FRAXE Syndromes, Fragile X Syndromes, Martin Bell Syndrome, Syndrome, FRAXA, Syndrome, FRAXE, Syndrome, Fragile X, Syndrome, Martin-Bell, Syndromes, FRAXA, Syndromes, FRAXE, Syndromes, Fragile X
| fragile X syndrome |
Fragile X Syndrome is the most common inherited cause of mental impairment, and the most common known cause of autism. Fragile X syndrome is a genetic disorder caused by a mutation of the FMR1 gene on the X chromosome, a mutation found in 1 out of every 2000 males and 1 out of every 4000 females. Typically the FMR1 gene contains between 6 and 53 repeats of the CGG codon. In people with the disorder, the FMR1 allele has over 230 repeats. ...
Ãâó: en.wikipedia.org/wiki/Fragile_X_syndrome
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| fragile X syndrome |
The commonest cause of severe mental retardation in males, caused by a long
Ãâó: www.jansen.com.au/Dictionary_DF.html
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| fragile X syndrome |
a syndrome resulting from a fragile or broken site on the X chromosome, often characterized by mental retardation, hypotonia and hyperactivity
Ãâó: depts.washington.edu/pwdlearn/web/glossary/glossar...
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| fragile X syndrome |
Martin-Bell syndrome. Marker X syndrome, Escalante syndrome. A genetic syndrome with the familial occurrence of moderate mental retardation. predominantly in males, who also demonstrate a long narrow face with thick features, prognathism (a prominent jaw), blue eyes, and, early in life, macrosomia (large body size), and later in life, macro-orchidism (large testicles). This is an X-linked disorder with a fragile site (FMR? gene) on the long arm of the X chromosome (Xq 27). ...
Ãâó: www.childrenwithchallenges.net/definitions/F.html
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| fragile X s. |
an X-linked syndrome associated with fragile site on the long arm of the X chromosome at q27.3, associated with mental retardation, enlarged testes, high forehead, and enlarged jaw and ears in most males and mild mental retardation in many heterozygous females. In some families there have been unaffected transmitting males.
Ãâó: www.mercksource.com/pp/us/cns/cns_health_library.j...
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