Family history

The genetic relationships within a family combined with the medical history of individual family members. When represented in diagram form using standardized symbols and terminology, it is usually referred to as a pedigree or family tree. (NCI Thesaurus)

Genetic anticipation

A phenomenon in which the signs and symptoms of some genetic conditions tend to become more severe and/or appear at an earlier age as the disorder is passed from one generation to the next. Huntington disease is an example of a genetic disorder in which the biological mechanism for this phenomenon has been well documented. In other cases, it may be due to factors such as increased surveillance or other nongenetic causes.

Triple-negative breast cancer

Triple-negative breast cancer is defined by a lack of expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2/neu).

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.

Germline

The cells from which eggs or sperm (i.e., gametes) are derived.

Inherited cancer syndrome

Describes the clinical manifestations associated with a mutation conferring cancer susceptibility.

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)

Pedigree

A graphic illustration of family history. (NCI Thesaurus)

Late or variable onset

The state in which a genetic trait is expressed later in life or is expressed at no fixed time in a life history.

Genetic screening

Genetic testing designed to identify individuals in a given population who are at higher risk of having or developing a particular disorder, or carrying a gene for a particular disorder.

Cancer screening

Clinical testing designed to identify the presence of a specific cancer in an asymptomatic individual or population thought to be at risk of that specific cancer. The intent is to find cancers at the earliest possible stage in their development, in order to improve the chances for disease cure. (NCI Thesaurus)

Noncarrier

An individual who does not carry a mutation previously identified in his or her family.

Unaffected

An individual who does not manifest symptoms of a condition or disease occurring in his or her family.

Nonpenetrance

The state in which a genetic trait, although present in the appropriate genotype, fails to manifest itself in the phenotype (e.g., a woman with a BRCA1 mutation who lives to be elderly and never develops breast or ovarian cancer).

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.