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The significance of the sickle-cell trait is that it does not show any symptoms, nor does it cause any major difference in blood cell count. The trait confers about 30% protection against malaria [clarification needed] and its occurrence appears to have risen tremendously in Africa, India and the Middle East. Some findings also show the ...
A heterozygote advantage describes the case in which the heterozygous genotype has a higher relative fitness than either the homozygous dominant or homozygous recessive genotype. Loci exhibiting heterozygote advantage are a small minority of loci. [1] The specific case of heterozygote advantage due to a single locus is known as overdominance.
The common MTHFR deficiencies are usually asymptomatic, although the 677T variant can cause a mildly increased risk of some diseases. [citation needed]For individuals homozygous in the 677T variant, there is a mildly elevated risk of thromboembolism (odds ratio 1.2), [4] and stroke (odds ratio 1.26). [5]
A person with a single abnormal copy does not usually have symptoms and is said to have sickle cell trait. [3] Such people are also referred to as carriers. [5] Diagnosis is by a blood test, and some countries test all babies at birth for the disease. [4] Diagnosis is also possible during pregnancy. [4]
In medical genetics, compound heterozygosity is the condition of having two or more heterogeneous recessive alleles at a particular locus that can cause genetic disease in a heterozygous state; that is, an organism is a compound heterozygote when it has two recessive alleles for the same gene, but with those two alleles being different from each other (for example, both alleles might be ...
The loss of heterozygosity is a common occurrence in cancer development. Originally, a heterozygous state is required and indicates the absence of a functional tumor suppressor gene copy in the region of interest.
An obligate carrier is an individual who may be clinically unaffected but who must carry a gene mutation based on analysis of the family history; usually applies to disorders inherited in an autosomal recessive and X-linked recessive manner.
A carrier is a person who inherited one abnormal gene from one of their parents. [2] Carriers often show no symptoms of the genetic disorder that they carry an abnormal gene for. Usually the only time a person finds out that they are a carrier for a specific genetic disorder is when they have an affected child. [2]