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recurrence risk
In genetics, the likelihood that a hereditary trait or disorder present in one family member will occur again in other family members. This is distinguished from recurrence risk for cancer, which is the chance that a cancer that has been treated will recur.
risk assessment
The quantitative or qualitative assessment of an individual’s risk of carrying a certain gene mutation, or developing a particular disorder, or of having a child with a certain disorder; sometimes done by using mathematical or statistical models incorporating such factors as personal health history, family medical history and ethnic background.
SDR
Second-degree relative. The aunts, uncles, grandparents, grandchildren, nieces, nephews, or half-siblings of an individual. Also called second-degree relative. (NCI Thesaurus)
second-degree relative
SDR. The aunts, uncles, grandparents, grandchildren, nieces, nephews, or half-siblings of an individual. Also called SDR. (NCI Thesaurus)
sensitivity
The frequency with which a test yields a true positive result among individuals who actually have the disease or the gene mutation in question. A test with high sensitivity has a low false-negative rate and thus does a good job of correctly identifying affected individuals.
single nucleotide polymorphism
SNP. DNA sequence variations that occur when a single nucleotide (adenine, thymine, cytosine, or guanine) in the genome sequence is altered; usually present in at least 1% of the population; pronounced "snip". Also called SNP. (NCI Thesaurus)
single-stranded conformational polymorphism
SSCP. A type of mutation scanning; the identification of abnormally-migrating single-stranded DNA segments on gel electrophoresis. Also called SSCP. (NCI Thesaurus)
SNP
Single nucleotide polymorphism. DNA sequence variations that occur when a single nucleotide (adenine, thymine, cytosine, or guanine) in the genome sequence is altered; usually present in at least 1% of the population; pronounced "snip". Also called single nucleotide polymorphism. (NCI Thesaurus)
Southern blot
Electrophoresis-based technique used in genetic testing to detect large deletions in DNA that can be missed by PCR-based genetic testing methods. (NCI Thesaurus)
specificity
The frequency with which a test yields a true negative result among individuals who do not have the disease or the gene mutation in question. A test with high specificity has a low false-positive rate and thus does a good job of correctly classifying unaffected individuals.
splicing
The process by which introns, the noncoding regions of genes, are excised out of the primary messenger RNA transcript, and the exons (i.e., coding regions) are joined together to generate mature messenger RNA. The latter serves as the template for synthesis of a specific protein. (NCI Thesaurus)
sporadic cancer
This term has two meanings. It is sometimes used to differentiate cancers occurring in people who do not have a germline mutation that confers increased susceptibility to cancer from cancers occurring in people who are known to carry a mutation. Cancer developing in people who do not carry a high-risk mutation is referred to as sporadic cancer. The distinction is not absolute, because genetic background may influence the likelihood of cancer even in the absence of a specific predisposing mutation. Alternatively, sporadic is also sometimes used to describe cancer occurring in individuals without a family history of cancer.
SSCP
Single-stranded conformational polymorphism. A type of mutation scanning; the identification of abnormally-migrating single-stranded DNA segments on gel electrophoresis. Also called single-stranded conformational polymorphism. (NCI Thesaurus)
susceptibility gene
A germline mutation that increases an individual’s susceptibility or predisposition to a certain disease or disorder. When such a mutation is inherited, development of symptoms is more likely, but not certain. Also called predisposing mutation. (NCI Thesaurus)
transcription
The process of synthesizing messenger RNA (mRNA) from DNA. (NCI Thesaurus)
translation
The process of synthesizing an amino acid sequence (protein product) from the messenger RNA code. (NCI Thesaurus)
trinucleotide repeat
Sequences of 3 nucleotides repeated in tandem on the same contiguous section of chromosome. A certain amount of normal (polymorphic) variation in repeat number with no clinical significance commonly occurs between individuals; however, repeat numbers over a certain threshold can, in some cases, lead to adverse effects on the function of the gene, resulting in genetic disease.
trisomy
The presence of an extra chromosome, resulting in a total of three copies of that chromosome instead of the normal 2 copies (e.g., trisomy 21, or Down syndrome). (NCI Thesaurus)
unaffected
An individual who does not manifest symptoms of a condition or disease occurring in his or her family.
unclassified variant
A variation in a genetic sequence whose association with disease risk is unknown. Also called variant of unknown significance, variant of uncertain significance, and VUS.
uninformative
A negative test result in an individual where a clearly deleterious mutation has not been found in any family members. The genetic risk status of such an individual must be interpreted in the context of their personal and family history.
Also called indeterminate and inconclusive.
variable expression
Variation in the manner in which a trait is manifested. When there is variable expressivity, the trait may vary in clinical expression from mild to severe. For example, the condition neurofibromatosis type 1 may be mild, presenting with café-au-lait spots only, or may be severe, presenting with neurofibromas and brain tumors.
variant of uncertain significance
VUS. A variation in a genetic sequence whose association with disease risk is unknown. Also called variant of unknown significance, unclassified variant, and VUS.
variant of unknown significance
VUS. A variation in a genetic sequence whose association with disease risk is unknown. Also called variant of uncertain significance, unclassified variant, and VUS.
VUS
Variant of uncertain significance. A variation in a genetic sequence whose association with disease risk is unknown. Also called variant of uncertain significance, variant of unknown significance, and unclassified variant.
No entries.
X-linked recessive
X-linked recessive inheritance refers to genetic conditions associated with mutations in genes on the X chromosome. A male carrying such a mutation will be affected, because he carries only one X chromosome. A female carrying a mutation in one gene, with a normal gene on the other X chromosome, will be unaffected.
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No entries.
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